Patent ID: 12244739

TERMS

Prior to discussing embodiments of the invention, description of some terms may be helpful in understanding embodiments.

The term “server computer” may include a computer or cluster of computing devices. For example, the server computer can be a large mainframe, a minicomputer cluster, or a group of servers functioning as a unit. In one example, the server computer may be a database server coupled to a Web server. The server computer may be coupled to a database and may include any hardware, software, other logic, or combination of the preceding for servicing the requests from one or more client computers. The server computer may include one or more computational apparatuses and may use any of a variety of computing structures, arrangements, and compilations for servicing the requests from one or more client computers.

The term “public/private key pair” may include a pair of linked cryptographic keys generated by an entity (e.g., a computer or an electronic device). The public key may be used for public functions such as encrypting a message to send to the entity or for verifying a digital signature which was supposedly made by the entity. The private key, on the other hand may be used for private functions such as decrypting a received message or applying a digital signature. The public key will usually be authorized by a body known as a Certification Authority (CA) which stores the public key in a database and distributes it to any other entity which requests it. The private key will typically be kept in a secure storage medium and will usually only be known to the entity. However, the cryptographic systems described herein may feature key recovery mechanisms for recovering lost keys and avoiding data loss. Public and private keys may be in any suitable format, including those based on RSA or elliptic curve cryptography (ECC).

A “digital signature” may refer to the result of applying an algorithm based on a public/private key pair, which allows a signing party to manifest, and a verifying party to verify, the authenticity and integrity of a document. The signing party acts by means of the private key and the verifying party acts by means of the public key. This process certifies the authenticity of the sender, the integrity of the signed document and the so-called principle of nonrepudiation, which does not allow disowning what has been signed. A certificate or other data that includes a digital signature by a signing party is said to be “signed” by the signing party.

A “certificate” or “digital certificate” may include an electronic document or data file that uses a digital signature to bind a public key with data associated with an identity. The certificate may include one or more data fields, such as the legal name of the identity, a serial number of the certificate, a valid-from and valid-to date for the certificate, certificate-related permissions, etc. A certificate may contain a “valid-from” date indicating the first date the certificate is valid, and a “valid-to” date indicating the last date the certificate is valid. A certificate may also contain a hash of the data in the certificate including the data fields. Unless otherwise noted, each certificate is signed by a certificate authority.

A “certificate authority” (CA) may include one or more server computers operatively coupled to issue certificates to entities. The CA may prove its identity using a CA certificate, which includes the CA's public key. The CA certificate may be signed by another CA's private key, or may be signed by the same CA's private key. The latter is known as a self-signed certificate. The CA may maintain a database of all certificates issued by the CA, and may also maintain a list of revoked certificates.

In a typical process, the certificate authority receives an unsigned certificate from an entity whose identity is known. The unsigned certificate includes a public key, one or more data fields, and a hash of the data in the certificate. The CA signs the certificate with a private key corresponding to the public key included on the CA certificate. The CA may then store the signed certificate in a database, and issue the signed certificate to the entity.

A “cryptographic nonce” may include any number, string, bit sequence, or other data value intended to be used in association with a single communication session. In some cases, a cryptographic nonce may be randomly or pseudo-randomly generated. Typically, a cryptographic nonce is of sufficient length as to make insignificant the likelihood of independently generating the same nonce value multiple times.

A “blinded key,” such as a “blinded public key” may include a key that has been obfuscated or otherwise modified from its original value by combination with another data element, such as a cryptographic nonce. For example, in elliptic curve cryptography, a public key may be multiplied by the nonce to generate a “blinded public key.” Similarly, a private key may be multiplied by the nonce to generate a “blinded private key.” The nonce may have the same bit-length as the public key and the private key.

An “ephemeral key pair” may include a public key (i.e., an “ephemeral public key”) and a private key (i.e., an “ephemeral private key) generated for use with a single transaction or other communication session. The ephemeral key pair may be of any suitable format, such as ECC or RSA. Typically, an ephemeral key pair is deleted once the transaction or communication session has concluded.

A “static key pair” may include a public key (i.e., a “static public key”) and a private key (i.e., a “static private key”) maintained over a period of time. Typically, though not necessarily, a static private key may be stored securely, such as in a hardware security module (HSM) or secure element (SE). Typically, though not necessarily, a static public key may be bound to an identity through the use of a digital certificate. The static key pair may be of any suitable format, such as ECC or RSA.

A “shared secret” may include any data value or other information known only to authorized parties in a secure communication. A shared secret can be generated in any suitable manner, from any suitable data. For example, a Diffie-Hellman based algorithm, such as Elliptic-Curve Diffie-Hellman (ECDH) may be used to generate a shared secret from a private key and a public key. For example, a first computer may generate a first key pair include a first public key and a first private key. A second computer may generate a second key pair including a second public key and a second private key. The first computer may generate a shared secret using the second public key of the second computer and the first private key of the first computer. The second computer may generate the same shared secret using the first public key of the first computer and the second private key of the second computer. The first computer and the second computer may both use the shared secret to generate a session key.

The term “identification data” may include any data or information associated with a user or device. Examples of identification data may include a name of a user associated with the device, an organization associated with the device, payment information such as a primary account number (PAN) associated with the device, an expiration date of the device, a certificate associated with the device, an IMEI or serial number of the device, etc.

The term “authentication” generally refers to a process of establishing confidence in the identity of a user or a computer. Certain electronic authentication systems may require a user to input authentication information (e.g., a password, a personal identification number (PIN), or other similar information) for authentication of the user. For example, a user may request access to a website by entering a user ID and a PIN into their user device, which communicates the user ID and PIN to a server hosting the website. The server may authenticate the user my comparing the user ID and PIN received from the user device to a stored PIN corresponding to that user ID. Authentication may also be performed by confirming the identity of a device through the use of public key cryptography and through the use of digital signatures.

The term “authentication data” or “authentication information” may include any data or information suitable to authenticate a user or device. Examples of authentication data may include a password or passphrase, a secret key (e.g., a private key), a digital signature, an indication that the device is storing certain information, etc.

The term “provisioning” generally refers to a process for requesting and receiving data. For example, a user device (e.g., a computer or a mobile device) may request data from a provisioning server to be stored on the user device. The provisioning server may send data to the user device may be based on certain criteria or rules. The provisioning server may send the data to the user device based on identifying the user device. The data provisioned to the user device from the provisioning server may generally be referred to as “provisioning data.” The provisioning data may be communicated using a channel established based on a public key identifying the user device.

An “identification factor” may include any data or information determined from identification data and/or authentication data. Typically, though not necessarily, the identification factor may be generated by hashing a combination of identification data and authentication data.

An “encryption key” may include any data value or other information suitable to cryptographically encrypt data. A “decryption key” may include any data value or other information suitable to decrypt encrypted data. In some cases, the same key used to encrypt data may be operable to decrypt the data. Such a key may be known as a symmetric encryption key.

A “session key” may include any key used to encrypt or decrypt data to be securely communicated. In some cases, a session key may be generated from a shared secret known both to a sending entity and a receiving entity. For example, the session key may be derived using a key derivation function and the shared secret.

DETAILED DESCRIPTION

Some embodiments of the invention relate to authentication systems and methods, provisioning systems and methods, and integrated authentication and provisioning systems.

I. Authentication

User devices (e.g., computers and mobile phones) may be used to access sensitive data and receive sensitive data. Such sensitive data may require an authentication process to ensure that unauthorized users do not access it. Authorization generally refers to a process of establishing confidence in the identity of a user. Certain electronic authentication systems may require a user to input authentication information (e.g., a password, a personal identification number (PIN), or other similar information) for authentication of the user. For example, a user may request access to a website by entering a user ID and a PIN into their user device, which communicates the user ID and PIN to a server hosting the website. The server may authenticate the user my comparing the user ID and PIN received from the user device to a stored PIN corresponding to that user ID. As such, the user device may only access the data if the user is authenticated. However, such authentication systems require the authentication information to be input at user device and stored at the server. Such systems may be vulnerable to a data breach, where an unauthorized party gains access to the stored authentication information at either the user device or the server.

In addition, such systems may be vulnerable to eavesdropping on the communications (e.g., by conducting a man-in-the-middle attack). Thus, an attacker may attempt to intercept identification data used to infer the identity of a user device or a server computer, or authentication data, such as a password or response to a challenge, transmitted by the user. If determined, this data could be used for illicit purposes. Further complicating matters is the prior state of the user device. In some cases, the user device may not previously store a digital certificate for a provisioning server—in other words, the user device may not trust a priori the provisioning server. Conducting secure and authenticated provisioning in such circumstances may pose a challenge.

Certain authentication systems may perform authentication without transmitting passwords, PINs, or similar authentication information to a server over a network in order to address the issues discussed above. For example, instead of the user device transmitting a user-input authentication information (e.g., password, PIN, or biometric data) to an online server, the user may authenticate with the user device by inputting the authentication information and the user device may authenticate with the server using public key cryptography.

FIG.1shows a message flow diagram100for registration and authentication of a user device120with an authentication server140, in accordance with some embodiments. The user device120may include a computing device operated by or associated with a user180. For example, the user devices120may be a mobile device, a payment devices (e.g., smart cards), a wearable device, a personal computer, etc. The authentication server140may be a server computer, or cluster of server computers, coupled to one or more databases. An authorization process may be performed, for example, when the user180of the user device120requests data or attempts to access a website maintained by a webserver (not shown) that requires authentication by the authentication server140. In order to authenticate with the authentication server140, the user device120must first perform registration with the authentication server140.

In performing registration, at101, the authentication server140may send a registration request to the user device120(e.g., over a network). The registration request may include parameters specifying authentication criteria for authentication of the user180. The registration request may also include a challenge. The registration request may be passed from the authentication server140through the webserver to the user device120.

In response to receiving the registration request, the user device120may prompt the user180to authenticate themselves. The user device120may require authentication of the user180based on the authentication criteria of the registration request. At102, the user180may input authentication information into the user device120. For example, the user180may input authentication information including at least one of a user identifier, a password, passcode, a PIN, a fingerprint scan, a retinal scan, or other biometric data. In response to receiving the authentication information input by the user180, the user device120may generate a user device authentication key pair (“UD Auth. Pub. & Priv. Key Pair”)126. The user device authentication key pair126includes a user device authentication public key (“UD Auth. Pub. Key”)128and a user device authentication private key corresponding to the user device authentication public key. The user device authentication key pair126may be uniquely identified with the user180and the authentication information input by the user180. The user device120may store the user device authentication key pair126(e.g., in a memory circuit).

Prior to registration, the user device120may store (e.g., in a memory circuit) a user device attestation key pair (“UD Atts. Pub. & Priv. Key Pair”)122including a user device attestation public key and a user device attestation private key corresponding to the user device attestation public key. For example, the user device attestation key pair122may be installed by an original equipment manufacturer during manufacture of the user device120. The user device120may also store a user device attestation certificate (“UD Atts. Cert.”)124. The user device attestation certificate124may include a user device attestation public key. The user device attestation public key of the user device attestation certificate124may be used to verify data that is signed using the user device attestation private key. The user device attestation certificate124may be signed by a trusted certificate authority (“CA”). The user device attestation certificate124may be verified using a CA public key of the CA corresponding to a CA private key of the CA used to signed the user device attestation certificate124. For example, the user device attestation certificate124may be installed by the original equipment manufacturer during manufacture of the user device120.

The user device120may sign the user device authentication public key128using the user device attestation private key. That is, the user device120may generate a signed user device authentication public key including a signature. The user device120may generate a registration response including the signed user device authentication public key128and the user device attestation certificate124. The registration response may also include the user device authentication public key128, the user device attestation certificate124, and a signature. The user device120may generate the signature by signing over the user device authentication public key128and the challenge of the registration request. At103, the user device120may send the registration response to the authentication server140(e.g., over a network). The registration response from the user device120may be passed through the webserver (not shown) to the authentication server140.

Prior to registration. the authentication server140may store the CA public key (e.g., in a memory circuit). The authentication server140may verify the user device attestation certificate using the CA public key. Then authentication server140may then verify the user device authentication public key128, which was signed by the user device120using the user device attestation private key, using the user device attestation public key of the user device attestation certificate124. The authentication server140may store the user device authentication public key128(e.g., in a memory circuit). Thus, the user device120has registered the user device authentication public key128with the authentication server140such that it may be used for authentication of the user device120.

After registration, the user180of the user device120may perform an authentication process to request the data or to access the website discussed above with respect to registration. At104, the authentication server140may send an authentication request to the user device120(e.g., over a network). The authentication request may be passed through the webserver. The authentication request may include an authentication challenge. In response to receiving the authentication request, the user device120may prompt the user180to authenticate themselves. At105, the user180may input the authentication information used during registration into the user device120. In response to receiving the authentication information input by the user180, the user device120may identify the user device authentication key pair126generated during registration by matching the authentication information input by the user180. The user device120may sign the authentication challenge using the user device authentication private key corresponding to the user device authentication public key128, which has been registered with the authentication server140, to obtain a signed authentication challenge. The signed authentication challenge includes a signature of the authentication challenge that may be verified using the user device authentication public key.

The user device120may generate an authentication response including the signed authentication challenge. At106, the user device120may send the authentication response to the authentication server140(e.g., over a network). The authentication response may be passed through a webserver. The authentication server140may verify the signed challenge of the authentication response using the user device authentication public key128stored at the authentication server140during registration. The authentication server140may send an indication to the webserver that the signature of the user device120has been verified and the webserver may provide the data or the website requested by the user device120to the user device120.

Thus, the user180authenticates with the user device120by inputting the authentication information (e.g., a PIN or biometric data) to the user device120and the user device120authenticates with the authentication server140by signing an authentication challenge using the user device authentication private key corresponding to the user device authentication public key128registered with the authentication server140.

II. Provisioning

Provisioning generally refers to a process for requesting and receiving data. For example, a user device (e.g., computers and mobile phones) may request data from a provisioning server to be stored on the user device. The provisioning server may send data to the user device may be based on certain criteria or rules. The data may be communicated using a channel established based on a public key identifying the user device. During provisioning, even if communications are encrypted or otherwise protected, the identity of the user device or a user or the user device may be determined. If determined, the identity could be used for illicit purposes.

FIG.2shows a message flow diagram200for confidentially provisioning data from a provisioning server260to a user device220, in accordance with some embodiments. AlthoughFIG.2shows the steps as being performed by user device220and provisioning server260, some or all steps may be performed by another suitable entity, such as an authentication server. The steps in the message flow diagram200may also be performed in a different order or in another suitable manner.

The user device220may include a computing device operated by or associated with a user. For example, the user devices120may be a mobile device, a payment devices (e.g., smart cards), a wearable device, a personal computer, etc. The user device220ofFIG.2may operate similarly to the user device120ofFIG.1. The provisioning server260may be a server computer, cluster of server computers, or a webserver coupled to one or more databases. Provisioning server260may provision data to the user devices220. For example, the provisioning data may include account information, identification information, documents, payment credentials, or other data or information. In some embodiments, the provisioning server260may be implemented using one or more server computers and/or other computing devices.

Prior to the message flow200, the user device220may store (e.g., in a memory circuit) a certificate authority (CA) root certificate (“CA Cert.”)232including a CA root public key. Prior to the message flow200, the provisioning server260may maintain a provisioning server key pair (“PS Priv. & Pub. Key Pair”)262including a provisioning server public key and a provisioning server private key corresponding to the provisioning server public key. The provisioning server260may also maintain a provisioning server certificate (“PS Cert.”) including the provisioning server public key. The provisioning server certificate252may be signed by the CA root public key.

In order to encrypt communications between the user device220and the provisioning server260, the user device220may generate a shared secret using a private key of the user device220and a public key of the provisioning server260. The provisioning server260may generate the same shared secret using a private key of the provisioning server and a public key of the user device220corresponding to the private key of the user device220. In some embodiments, the user device220may store a provisioning server certificate (“PS Cert.”)264of the provisioning server260. The provisioning server certificate264may include a provisioning server public key that may be used by the user device220to generate a shared secret for encrypting communications. However, in some embodiments, the user device220may not store the provisioning server certificate264and may need to receive it from the provisioning server260.

The user device220may generate a user device ephemeral key pair (“UD Eph. Pub. & Priv. Key Pair”)234including a user device ephemeral public key and a user device ephemeral private key corresponding to the user device ephemeral public key. At201, the user device220sends the user device ephemeral public key to the provisioning server260. The user device ephemeral public key may not be used to identify the user device220because the user device220may only use the user device ephemeral public key for a single communication (e.g., to receive the provisioning server certificate264). The user device220may not store the user device ephemeral key pair after it has performed the communication.

The provisioning server260may store (e.g., in a memory circuit) a provisioning server key pair (“PS Pub. & Priv. Key Pair”)262include a provisioning server private key corresponding to the provisioning server public key. The provisioning server260may also store the provisioning server certificate264. The provisioning server certificate264may be signed by the CA using the CA private key. The provisioning server260may modify the provisioning server public key such that it may not be used to identify the provisioning server260. For example, the provisioning server260may generate a provisioning server blinding factor (e.g., a cryptographic nonce), and use the provisioning server public key and the provisioning server blinding factor to generate a blinded provisioning server public key. For example, the provisioning server260may generate the blinded provisioning server public key by performing a multiplication operation on the provisioning server public key and the provisioning server blinding factor.

The provisioning server260may generate a first shared secret using the user device ephemeral public key, the provisioning server private key, and the provisioning server blinding factor. The provisioning server260may use the first shared secret to generate a first session key for communicating with the user device220. The provisioning server260may encrypt the provisioning server certificate264using the first session key to obtain an encrypted provisioning server certificate. In some embodiments, the provisioning server260may also encrypt the provisioning server blinding factor using the first session key to obtain an encrypted provisioning server blinding factor. At202, the provisioning server260sends (e.g., over a network) the blinded provisioning server public key and the encrypted provisioning server certificate to the user device220. The provisioning server260may also send one or more of an encrypted authentication cryptogram, encrypted meta-data, and the encrypted provisioning server blinding factor to the user device220.

The user device220may receive the blinded provisioning server public key and the encrypted provisioning server certificate from the provisioning server260. The user device220may generate the same first shared secret generated by the provisioning server260, using the blinded provisioning server public key and the user device ephemeral private key. The user device220may generate the first session key using the first shared secret. The user device220may use the first session key to decrypt the encrypted provisioning server certificate to obtain the provisioning server certificate. In some embodiments, the user device220may also receive and decrypt the encrypted provisioning server blinding factor. The user device220may verify the provisioning server certificate264using the CA public key of the CA certificate232. In some embodiments, the user device220may verify the blinded provisioning server public key using the provisioning server blinding factor and the provisioning server public key of the provisioning server certificate264. In some embodiments, the user device220may also receive and decrypt the encrypted authentication cryptogram and may also validate the authentication cryptogram. The user device220may store the provisioning server certificate264(e.g., in a memory circuit).

Thus, the user device220may confidentially obtain the provisioning server certificate264if it did not already have it stored. In some embodiments, where user device220already stores the provisioning server certificate264, the messaging at201and202may be skipped.

At203, user device220may encrypt identification data to obtain encrypted identification data. The user device220may send the encrypted identification data to provisioning server260(e.g., over a network). In some embodiments, such as those where messaging201and202were previously performed, the user device220may use the previously established shared secret to perform the encryption and decryption described with reference to messaging203and204. In other embodiments, such as those where messaging201and202were not performed, the encryption and decryption described above with reference to the messaging203may be performed using a second shared secret generated based on the stored provisioning server certificate264. The provisioning server260may encrypt the provisioning data using the shared secret established for the messaging at202or using the second shared secret. At204, the provisioning server260sends the encrypted provisioning data to the user device220. In some embodiments, provisioning server260may also send a blinded provisioning server public key, an authentication cryptogram, meta-data, and/or a new encrypted server certificate (e.g., new server credentials to be used in future communication with provisioning server260) to the user device220.

Thus, the message flow ofFIG.2enables the user device220to obtain provisioning data from the provisioning server260while maintaining confidentiality of its identity.

III. Provisioning with Authentication

In some embodiments, an authentication server (e.g., authentication server140) may offer authentication capabilities “as a service” (e.g., using an API or other interface accessible by other entities) to a provisioning server (e.g., provisioning server260). For example, a provisioning server may interface with authentication server in order to authenticate a user device (e.g., user device120or user device220) prior to provisioning data to the user device. The provisioning server may only perform a provisioning process in response to the user being authenticated. In some embodiments, both the authentication server and the provisioning server may be implemented on the same set of computing devices, or may be operated by the same entity.

FIG.3shows a message flow diagram300for authenticating a user device320and provisioning data to the user device320, in accordance with some embodiments. The user device320ofFIG.3may operate similar to the user devices110,220described above. The authentication server340ofFIG.3may operate similar to the authentication server140described above. The provisioning server360ofFIG.3may operate similar to the provisioning server260described above. AlthoughFIG.3shows the messaging as being performed by the user device320, the authentication server340, and the provisioning server360, some or all of the messaging steps may be performed by another suitable entity. For example, the authentication server340and the provisioning server360may perform certain operations instead of the other or the authentication server340and the provisioning server360may be combined. In addition, the messaging shown inFIG.3may be performed in a different order or in another suitable manner.

Prior to the message flow300, the user device320may store (e.g., in a memory circuit) a user device attestation key pair (“UD Atts. Pub. & Priv. Key Pair”)322including a user device attestation public key and a user device attestation private key corresponding to the user device attestation public key. The user device320may also store a user device attestation certificate (“UD Atts. Cert.”)324including the user device attestation public key. The user device attestation certificate may be signed by a CA using a private key of the CA. Prior to the messaging flow300, the authentication server340may store (e.g., in a memory circuit) a CA certificate including a CA public key corresponding to the CA private key. The CA public key may be used to verify data signed by the CA private key.

The user device320may register and authenticate with the authentication server340in a process similar to the registration and authentication process described above with reference toFIG.1. At301, the authentication server340may send a registration request to the user device320. The registration request at301ofFIG.3may be structured similar to the registration response at101ofFIG.1described above. In response to receiving the registration request, the user device may authenticate a user of the user device320and generate a user device authentication key pair (“UD Auth. Pub. & Priv. Key Pair”)326. The user device authentication key pair326may include a user device authentication public key328and a user device authentication private key corresponding to the user device authentication public key328. The user device320may store (e.g., in a memory circuit) the user device authentication key pair326.

At302, the user device320may send a registration response to the authentication server340. The registration response at302ofFIG.3may be structured similar to the registration response at103ofFIG.1described above. For example, the registration response may include an application ID, the user device attestation certificate324, and the user device authentication public key328signed by the user device attestation private key.

The authentication server340may verify the user device attestation certificate324using the CA public key of the CA certificate. The authentication server340may also verify the user device authentication public key328using the user device attestation public key of the user device attestation certificate324.

In some embodiments, prior to303, the user device320may communicate with either the authentication server340or the provisioning server360. For example, the user device320may send a message to initiate an authentication process. In response to the user device320initiating the authentication process, the provisioning server360may request an authentication request from the authentication server340. The provisioning server360may receive the authentication request from the authentication server340.

At303, the provisioning server360may send the authentication request to the user device320. The authentication request at303ofFIG.3may be structured similar to the authentication request at104ofFIG.1described above. For instance, the authentication request may include an authentication challenge.

The user device320may process the authentication request. Processing the authentication request may include adding additional data to the received authentication challenge, authenticating or verifying a user of user device320, and signing the challenge using the user device authentication private key stored at the user device320as described above with reference toFIG.1. At304, the user device320sends an authentication response including the signed challenge data, and possibly other data, to the provisioning server360.

The provisioning server360may send the authentication response from the user device320to the authentication server340. The authentication server340may verify the signed authentication challenge using the user device authentication public key328stored at the authentication server340. In some embodiments, the authentication server340may also verify that the signed authentication challenge matches the authentication challenge of the authentication request. Thus, the user device320may register with the authentication server340and be authenticated by the authentication server340.

At305, the authentication server340may send an indication that the signed authentication challenge has been verified to the provisioning server360. The provisioning server360may provide provisioning data to the user device320based on whether the signed authentication challenge is verified. For instance, if the provisioning server360does not receive an indication from the authentication server340that the signature of the signed authentication challenge is valid, then the provisioning server360may not provide provisioning data to the user device320.

If the provisioning server360receives, from the authentication server340, an indication that the signature of the signed authentication challenge is valid, then the provisioning server360and the user device320may perform a provisioning process similar to the provisioning process described above with reference toFIG.2. For instance, at306, the user device320may send the identification data to provisioning server360. In response to receiving the identification information, at307, the provisioning server360may send provisioning data to the user device307. The messaging at306and307for provisioning may be encrypted using a user device ephemeral key pair (“UD Eph. Pub. & Priv. Key Pair”)334similar to the encryption process described above with reference toFIG.2. As such, the provisioning server360may provision data to the user device320based on authentication of the user device320with the authentication server340.

IV. Confidential Authentication and Provisioning

The authentication and provisioning process described above with respect toFIG.3enables a provisioning server to provision data to a user device based on authentication of that user device with the authentication server. While the provisioning process described above may provide confidentiality to the user device through the use of an ephemeral key pairs and blinded public keys, the authentication process does not provide such confidentiality. In authentication, the user device may still be tracked based on the transmission of its signature (e.g., in signed data) or its public key. The systems and methods described below address this issue.

A. Authentication Using a Stored Provisioning Server Certificate

FIG.4shows a message flow diagram400including an authentication response and provisioning data that are confidential and secure, in accordance with some embodiments. The message flow400shows messaging between the user device420that is pre-loaded with a provisioning server certificate, an authentication server440, and a provisioning server460. The user device420ofFIG.4may operate similar to the user device320described above. The authentication server440ofFIG.4may operate similar to the authentication server340described above. The provisioning server460ofFIG.4may operate similar to the provisioning server360described above. The messaging ofFIG.4may be performed in a different order or in another suitable manner. The authentication server440and the provisioning server460may perform certain operations instead of the other or the authentication server440and the provisioning server460may be combined

Prior to the message flow400, the user device420may store (e.g., in a memory circuit) a user device attestation key pair (“UD Atts. Pub. & Priv. Key Pair”)422including a user device attestation public key and a user device attestation private key. The user device420may also store a user device attestation certificate424including the user device attestation public key. In addition, the user device420may store a provisioning server certificate (“PS Cert.”)464that includes a provisioning server public key and is signed by a certificate authority (“CA”) using a private key of the CA. The user device420may also pre-generate and store a user device ephemeral key pair (“UD Eph. Pub. & Priv. Key Pair”)434including a user device ephemeral public key and a user device ephemeral private key corresponding to the user device ephemeral public key.

Prior to message flow400, the provisioning server460may store (e.g., in a memory circuit) a provisioning server key pair (“PS Pub. & Priv. Key Pair”)462including a provisioning server public key and a provisioning server private key corresponding to the provisioning server public key. The provisioning server460may also store the provisioning server certificate464. The provisioning server certificate464may include the provisioning server public key and it may be signed by the CA using a CA private key.

The user device420may register with the authentication server440in a process similar to the registration process described above with reference toFIG.3. At401, the authentication server440may send a registration request to the user device420. The registration request at401ofFIG.4may be structured similar to the registration responses described above. In response to receiving the registration request, the user device420may authenticate a user of the user device420and generate a user device authentication key pair (“UD Auth. Pub. & Priv. Key Pair”)426. The user device authentication key pair426may include a user device authentication public key428and a user device authentication private key corresponding to the user device authentication public key428. The user device420may store (e.g., in a memory circuit) the user device authentication key pair426.

At402, the user device420may send a registration response to the authentication server440. The registration response at402ofFIG.4may be structured similar to the registration responses described above. For example, the registration response may include the user device attestation certificate424and the user device authentication public key428signed by the user device attestation private key.

The authentication server440may store a CA certificate and may verify the user device attestation certificate424using the CA public key of the CA certificate. The authentication server440may also verify the user device authentication public key428using the user device attestation public key of the user device attestation certificate424. In some embodiments, the authentication server440may store the provisioning server certificate464and the authentication server440may send the provisioning server certificate464to the user device420in response to verifying the user device authentication public key428. In other embodiments, the user device420may obtain the provisioning server certificate464prior to registration.

After registration, the user device420may initiate authentication. For example, the user device420may send a message to the provisioning server460to initiate an authentication process. In response to the user device420initiating the authentication process, the provisioning server460may request an authentication request from the authentication server440. The provisioning server460may receive the authentication request from the authentication server440.

At403, the provisioning server460may send the authentication request to the user device420. The authentication request at403ofFIG.3may be structured similar to the authentication requests described above. For instance, the authentication request may include an authentication challenge.

The user device420may processes the authentication request. Processing the authentication request may include adding additional data to the received authentication challenge, authenticating or verifying a user of user device320, and signing the challenge using the user device authentication private key stored at the user device420.

In contrast to the authentication processes described above with respect toFIGS.1and3, in this embodiment, the user device420may confidentially transmit an encrypted authentication response. The user device420may generate the user device ephemeral key pair434if it was not pre-generated. The user device420may generate a shared secret using the user device ephemeral private key and the provisioning server public key of the stored provisioning server certificate464. The user device may generate a session key based on the shared secret and encrypt the authentication response using the session key to obtain an encrypted authentication response.

At404, the user device420may send the user device ephemeral public key and the encrypted authentication response including the signed challenge data to the provisioning server460. As such, the authentication response at403maintains confidentiality because the user device ephemeral key pair434may not be used to identify or track the user device420since it may only be used to encrypt a limited number of messages (e.g., the authentication response only or the authentication response and the provisioning data). In addition, the authentication response is secured because it is encrypted using the shared secret.

The provisioning server460may receive the user device ephemeral public key and the encrypted authentication response from the user device420. The provisioning server460may generate the same shared secret generated by the user device420using the provisioning server private key and the user device ephemeral public key. The provisioning server460may generate the session key using the shared secret and use the session key to decrypt the encrypted authentication response to obtain the authentication response. The provisioning server460may send the authentication response to the authentication server440.

The authentication server440may verify the signed authentication challenge of the authentication response using the stored user device authentication public key428. For example, the signed challenge data may be decrypted using the user device authentication public key428to obtain a decrypted challenge, which may be compared to the authentication challenge included in the authentication request. The signed authentication challenge may be verified based on whether the decrypted challenge matches an expected value. At406, the authentication server440may send an indication that the signed authentication challenge has been verified to the provisioning server460.

The provisioning server460may provide provisioning data the user device420based on whether the signed authentication challenge is verified. For instance, if the provisioning server460does not receive an indication from the authentication server440that the signature of the signed authentication challenge is valid, then the provisioning server460may not provide provisioning data to the user device420. The provisioning server460may encrypt the provisioning data. In some embodiments, the provisioning server460may encrypt the provisioning data using the shared secret. In other embodiments, the provisioning server460may generate a second shared secret for encrypting the provisioning data. For example, the provisioning server460may blind the provisioning server key pair462using a provisioning server blinding factor (e.g., a cryptographic nonce) to obtain a blinded provisioning server public key and a blinded provisioning server private key. The provisioning server460may then derive the second shared secret using the blinded provisioning server private key and the user device ephemeral public key. The provisioning server460may encrypt the provisioning data using the second shared secret to obtain encrypted provisioning data. At405, the provisioning server460may send the blinded provisioning server public key and the encrypted provisioning data to the user device420.

The user device420may decrypt the encrypted provisioning data to obtain provisioning data and the user device430may store the provisioning data (e.g., in a memory circuit). For example, in embodiments where the user device420receives the encrypted payment credential and the blinded provisioning server public key, the user device420may generate the second shared secret using the user device ephemeral private key and the blinded provisioning server public key. The user device420may use the second shared secret to decrypt the encrypted provisioning data.

As such, the user device420may send an authentication response that is confidential and secure since the authentication response is encrypted and the public key sent to the provisioning server460for decryption is an ephemeral key. The provisioning data is also secure since it is encrypted as described above.

B. Authentication Including Transfer of a Provisioning Server Certificate

The authentication process as described above with respect toFIG.4uses a provisioning server certificate that is stored on the user device prior to authentication. However, in some cases, the user device may not store the provisioning server certificate prior to the authentication process. In such cases, the provisioning server certificate may need to be transferred to the user device as part of the provisioning process, rather than being assumed to have been previously loaded onto user device.

FIG.5shows a message flow500including authentication of a user device520that may not store a provisioning server certificate564, in accordance with some embodiments. Compared to the message flow400ofFIG.4, the message flow500ofFIG.5includes an encrypted authentication response. The message flow500shows messaging between the user device520, an authentication server540, and a provisioning server560. The user device520ofFIG.5may operate similar to the user devices described above. The authentication server540ofFIG.5may operate similar to the authentication servers described above. The provisioning server560ofFIG.5may operate similar to the provisioning servers described above. The messaging ofFIG.5may be performed in a different order or in another suitable manner. The authentication server540and the provisioning server560may perform certain operations instead of the other or the authentication server540and the provisioning server560may be combined.

Prior to message flow500, the user device520may store (e.g., in a memory circuit) a user device attestation key pair (“UD Atts. Pub. & Priv. Key Pair”)522including a user device attestation public key and a user device attestation private key. The user device520may also store a user device attestation certificate524including the user device attestation public key. In addition, the user device520may store a CA certificate (“CA Cert.”)532that includes a CA public key. The user device520may also pre-generate and store a user device ephemeral key pair (“UD Eph. Pub. & Priv. Key Pair”)534including a user device ephemeral public key and a user device ephemeral private key corresponding to the user device ephemeral public key.

Prior to message flow500, the provisioning server560may store (e.g., in a memory circuit) a provisioning server key pair (“PS Pub. & Priv. Key Pair”)562including a provisioning server public key and a provisioning server private key corresponding to the provisioning server public key. The provisioning server560may also store the provisioning server certificate564. The provisioning server certificate564may include the provisioning server public key and it may be signed by the CA using a CA private key.

The user device520may register with the authentication server540in a process similar to the registration process described above with reference toFIG.4. At501, the authentication server540may send a registration request to the user device520. The registration request at501ofFIG.5may be structured similar to the registration responses described above. In response to receiving the registration request, the user device520may authenticate a user of the user device520and generate a user device authentication key pair (“UD Auth. Pub. & Priv. Key Pair”)526. The user device authentication key pair526may include a user device authentication public key528and a user device authentication private key corresponding to the user device authentication public key528. The user device520may store (e.g., in a memory circuit) the user device authentication key pair526.

At502, the user device520may send a registration response to the authentication server540. The registration response at502ofFIG.5may be structured similar to the registration responses described above. For example, the registration response may include the user device attestation certificate524and the user device authentication public key528signed by the user device attestation private key.

The authentication server540may store a CA certificate and may verify the user device attestation certificate524using the CA public key of the CA certificate. The authentication server540may also verify the user device authentication public key528using the user device attestation public key of the user device attestation certificate524.

After registration, the user device520may initiate authentication. For instance, at503, the user device520may send the user device ephemeral public key to provisioning server560. The user device520may generate the user device ephemeral key pair534if it was not pre-generated.

The provisioning server560may request and receive an authentication request including an authentication challenge from the authentication server540. The provisioning server560may generate a provisioning server blinding factor (e.g., a cryptographic nonce) and use the provisioning server blinding factor to generate a blinded provisioning server public key and a blinded provisioning server private key based on the provisioning server key pair (“PS Pub. & Priv. Key Pair”)564. The provisioning server560may generate a shared secret using the user device ephemeral public key and the blinded provisioning server private key. The provisioning server560may encrypt the authentication request using the shared secret to obtain an encrypted authentication request. At504, the provisioning server560may send the blinded provisioning server public key and the encrypted authentication request to the user device520. The provisioning server may also encrypt and send, to the user device520, the provisioning server certificate564, the provisioning server blinding factor, an authentication cryptogram, meta-data, and the encrypted data.

The user device520may receive the blinded provisioning server public key and the encrypted authentication request from the provisioning server. The user device520may generate the shared secret using the blinded provisioning server public key and the user device ephemeral private key. The user device520may decrypt the encrypted authentication request using the shared secret to obtain the authentication request. In some embodiments, the user device520may also receive and decrypt, using the shared secret, the provisioning server certificate564, an authentication cryptogram, and the provisioning server blinding factor. The user device520may verify the provisioning server certificate564using the CA certificate532. The user device520may verify the blinded provisioning server public key using the provisioning server certificate and a provisioning server public key obtained from the provisioning server certificate564. The user device520may also validate the authentication cryptogram.

As such, the authentication request at504maintains confidentiality because the blinded provisioning server public key may not be used to identify or track the provisioning server560since the provisioning server blinding factor was applied to the provisioning server public key. In addition, the authentication request is secured because it is encrypted using the shared secret.

The user device520may receive the blinded provisioning server certificate and the encrypted authentication request. The user device520may generate the shared secret using the blinded provisioning server public key and the user device ephemeral private key corresponding to the user device ephemeral public key. The user device520may use the shared secret to decrypt the encrypted authentication request to obtain the authentication request. The user device520may processes the authentication request. Processing the authentication request may include adding additional data to the authentication challenge included in the authentication request, verifying a user of the user device520, and signing the authentication challenge using the user device authentication private key stored by the user device520.

The user device520may generate an authentication response including the signed authentication challenge. At505, the user device520sends an encrypted authentication response to provisioning server560. In some embodiments, the user device520may use the shared secret to encrypt the authentication response. In other embodiments, the user device520may generate a second shared secret for encrypting the authentication response using a second user device key pair (e.g., another ephemeral key pair). In such embodiments, the user device520may send the second user device ephemeral public key to the provisioning server560.

The provisioning server560may receive the encrypted authentication response. The provisioning server560may decrypt the encrypted authentication response using the shared secret to obtain the authentication response. In some embodiments, where the user device520sends the second user device ephemeral public key, the provisioning server may generate the second shared secret using the provisioning server private key and the second user device ephemeral public key. The provisioning server560may send the authentication response to the authentication server540.

The authentication server540may verify the signed authentication challenge of the authentication response using the stored user device authentication public key528. For example, the authentication server540may decrypt the signed authentication challenge and it may be compared to the authentication challenge of the authentication request. The signed authentication challenge may be verified based on whether the decrypted challenge matches an expected value. At507, the authentication server540may send an indication that the signed authentication challenge has been verified to the provisioning server460.

The provisioning server560may provide provisioning data the user device520based on whether the signed authentication challenge is verified. For instance, if the provisioning server560does not receive an indication from the authentication server540that the signature of the signed authentication challenge is valid, then the provisioning server560may not provide provisioning data to the user device520. The provisioning server560may encrypt the provisioning data. In some embodiments, the provisioning server560may encrypt the provisioning data using the shared secret to obtain encrypted provisioning data. In other embodiments, the provisioning server560may encrypt the provisioning data using the second shared secret. At506, the provisioning server560may send the encrypted provisioning data to the user device520.

As such, the authentication request at504maintains confidentiality because the blinded provisioning server public key may not be used to identify or track the provisioning server560since the provisioning server blinding factor was applied to the provisioning server public key. In addition, the authentication request, the authentication response, and the provisioning data are secured because they encrypted.

V. Improved Confidential Registration, Authentication, and Provisioning

Certain registration and authentication processes may be vulnerable to man-in-the-middle attacks. For example, a malicious device may masquerade as a legitimate user device while performing the registration or authentication. This may allow the malicious device to obtain in clear-text an authentication request sent by a provisioning server. Although the malicious device may not be able to sign an authentication challenge using the legitimate user device's private key, it may be possible (e.g., using malware installed on the legitimate user device), to obtain the user device's signature of the authentication challenge. The malicious device may then use the signed authentication challenge to respond to the provisioning server. In this manner, the malicious device may be able to obtain provisioning data for which it is unauthorized.

Some embodiments address this issue by encrypting communication between a user device and a provisioning server using a user device authentication key that is registered with an authentication server. This precludes entities that do not have the user device authentication private key of the user device from receiving a clear-text authentication request or authentication challenge, thereby preventing the man-in-the-middle attack described above.

FIG.6shows a message flow diagram600for securely provisioning data to a user device using a registered user device authentication public key, in accordance with some embodiments. The message flow600shows messaging between the user device620, an authentication server640, and a provisioning server660. The user device620ofFIG.6may operate similar to the user devices described above. The authentication server640ofFIG.6may operate similar to the authentication servers described above. The provisioning server660ofFIG.6may operate similar to the provisioning servers described above. The messaging ofFIG.6may be performed in a different order or in another suitable manner. In addition, althoughFIG.6shows the messaging as being performed by the user device620, the authentication server640, and the provisioning server660, it should be noted some or all steps may be performed by another suitable entity. The authentication server640and the provisioning server660may perform certain operations instead of the other or the authentication server640and the provisioning server660may be combined.

Prior to message flow600, the user device620may store a user device attestation key pair (“UD Atts. Pub & Priv. Key Pair”)622including a user device attestation public key and a user device attestation private key corresponding to the user device attestation public key. The user device620may also store a user device attestation certificate including the user device attestation public key. The user device620may also store a certificate authority certificate (“CA Cert.”)632including a CA public key.

Prior to message flow600, the provisioning server660may store a provisioning server key pair (“PS Pub. & Priv. Key Pair”)662including a provisioning server public key and a provisioning server private key corresponding to the provisioning server public key. The provisioning server660may also store a provisioning server certificate (“PS Cert.”) that includes the provisioning server public key and is signed by the certificate authority.

Prior to the message flow600, the authentication server640may store an authentication server certificate (“AS Cert.”)646, including an authentication server public key, that is signed by a CA. the authentication server640may also store an authentication server key pair (“AS Pub. & Priv. Key Pair)642including the authentication server public key and an authentication server private key corresponding to the authentication server public key.

As discussed above, the registration processes registers an authentication public key of a user device with an authentication server. In addition, the registration process ofFIG.6may establish a shared secret between the user device620and the authentication server640, and registration may be conducted using a session key determined from the shared secret.

The user device620may generate a user device ephemeral key pair including a user device ephemeral public key and a user device ephemeral private key corresponding to the user device ephemeral public key. At601, user device620may sends the user device ephemeral public key to authentication server640.

The authentication server640may generate an authentication server blinding factor (e.g., a cryptographic nonce) and combine the blinding factor with the authentication server key pair to generate a blinded authentication server public key and a blinded authentication server private key. Authentication server640may generate a shared secret using the user device ephemeral public key and the blinded authentication server private key. The authentication server640may use the shared secret to generate a session key. The authentication server640may encrypt the authentication server certificate644, the authentication server blinding factor, and a registration request using the shared secret to obtain, respectively, an encrypted authentication server certificate, an encrypted authentication server blinding factor, and an encrypted registration response. At602, the authentication server640may send the blinded authentication server public key and the encrypted registration request to the user device620. The authentication server640may also send an encrypted authentication cryptogram, encrypted meta-data, the encrypted authentication server certificate, and the encrypted authentication server blinding to user device620.

The user device620may generate the same shared secret as generated by authentication server640using the blinded authentication server public key and the user device ephemeral private key. The user device620may generate a session key using the shared secret. The user device620may use the shared secret to decrypt the encrypted registration request to obtain the registration request. The user device620may also use the shared secret to decrypt the encrypted authentication server certificate644and the encrypted authentication server blinding factor. The user device620may verify the authentication server certificate644using the CA certificate632. The user device620may verify the blinded authentication server public key using the authentication server blinding factor an authentication server public key obtained from the authentication server certificate644. The user device620may also validate the authentication cryptogram.

The user device620may require authentication of a user of the user device720based on the registration request. To authenticate, the user may input authentication information into the user device720. For example, the user may input authentication information including at least one of a user identifier, a password, passcode, a PIN, a fingerprint scan, a retinal scan, or other biometric data. In response to authenticating the user, the user device620may generate a user device authentication key pair (UD Auth. Pub. & Priv. Key Pair”)626including a user device authentication public key628and a user device authentication private key corresponding to the user device authentication public key. The user device720may associate the input authentication information with the user device authentication key pair. The user device620may sign the user device authentication public key628using the user device attestation private key to obtain a signed user device authentication public key. The user device620may generate a registration response including the signed user device authentication public key and the user device attestation certificate. The user device620may encrypt the registration response using the shared secret.

At603, the user device620may send the encrypted registration response to authentication server640. In some embodiments, the authentication response can be encrypted using the shared secret. In other embodiments, the user device620may generate a second registration shared secret for encrypting the registration response.

The authentication server640may decrypt the encrypted registration response using the shared secret to obtain the registration response. The authentication server640may verify the user device attestation certificate624using a CA public key. The authentication server640may also verify the user device authentication public key628using the user device attestation public key of the user device attestation certificate624.

As such, the user device620may confidentially register with the authentication server640using the user device ephemeral public key since it may not be used to identify or track the user device620. In addition, the registration request and the registration response are secured because they are encrypted using the shared secret.

In an authentication process, the user device620may generate a user device blinding factor, which may be a cryptographic nonce. The user device620may blind the user device authentication key pair626using the user device blinding factor to determine a blinded user device authentication public key and a blinded user device authentication private key. At604, the user device620may send the blinded user device authentication public key to the provisioning server660.

The provisioning server660may generate a provisioning server blinding factor, such as a cryptographic nonce. The provisioning server660may blind the provisioning server key pair662using the provisioning server blinding factor to obtain a blinded provisioning server public key and a blinded provisioning server private key. The provisioning server660may generate an authentication shared secret using the blinded user device authentication public key and the blinded provisioning server private key. The provisioning server660may obtains an authentication request for the user device620from the authentication server640. The authentication request may include an authentication challenge. The provisioning server660may encrypt the provisioning server certificate664, the provisioning server blinding factor, and the authentication request using the authentication shared secret to obtain, respectively, an encrypted provisioning server certificate, an encrypted provisioning server blinding factor, and an encrypted authentication request. At605, the provisioning server660may send the blinded provisioning server public key and the encrypted authentication request to the user device620. The provisioning server660may also send the encrypted provisioning server certificate and the encrypted provisioning server blinding factor to the user device620.

The user device620may generate the authentication shared secret using the blinded provisioning server public key and the blinded user device authentication private key. The user device620may decrypt the encrypted authentication request, the encrypted provisioning server certificate, and the encrypted provisioning server blinding factor using the authentication shared secret to obtain, respectively, the authentication request, the provisioning server certificate, and the provisioning server blinding factor. The user device620may verify the provisioning server certificate using the CA certificate632, and may verify the blinded provisioning server public key using the provisioning server blinding factor and a provisioning server public key obtained from the provisioning server certificate664.

The user device may process the authentication request. Processing the authentication request may include adding additional data to the received challenge, authenticating a user of user device620(e.g., by requiring the authentication information input at registration to be input by the user), and signing the authentication challenge in the authentication request using the user device authentication private key stored at the user device620. The user device may generate an authentication response including the signed authentication challenge. The user device620may encrypt the user device blinding factor and the authentication response using the authentication shared secret to obtain an encrypted user device blinding factor and an encrypted authentication response, respectively. At606, the user device620may send the encrypted authentication response to provisioning server660. The user device620may also send the encrypted user device blinding factor to the provisioning server660.

The provisioning server660may use the authentication shared secret to decrypt the encrypted authentication response and the encrypted user device blinding factor to obtain the authentication response and the user device blinding factor, respectively. The provisioning server may send the authentication response to the authentication server640. The authentication server640may verify the signed challenge using the user device authentication public key628stored at the authentication server640during registration of the user device620. For example, the signed challenge may be verified by decrypted, using the user device authentication public key628, and it may be compared to the authentication challenge of the authentication request. If the signed authentication challenge matches an expected value, then the authentication server may authenticate the user device620. At608, the authentication server640may send an indication to the provisioning server660that the signed challenge has been verified.

The provisioning server660may verify the blinded user device authentication public key by re-generating the blinded user device authentication public key using the user device blinding factor and the user device authentication public key628stored at the authentication server640. If the re-generated key matches the blinded user device authentication public key received at604, then the blinded user device public key is authenticated.

If the signed challenge and the blinded user device authentication public key are authenticated, the provisioning server660may encrypt provisioning data for the user device620using the authentication shared secret. At607, the provisioning server660may send the encrypted provisioning data to the user device620.

As such, the user device authentication public key628registered with the authentication server640during registration may be used to generate a shared secret for encryption during authentication. This provides advantages over generating an ephemeral key pair for encrypting authentication since generating and using a key pair is computationally intense and requires the use of a large amount of computing resources. Thus, encrypting the authentication request and authentication response using the registered user device authentication public key628may use less computing resources compared to a process that generates and uses an ephemeral key pair.

Some embodiments of the invention can leverage the registration process described in method to convey additional information to user device. For example, embodiments can allow an authentication server to transfer an authentication server certificate including an authentication server public key to the user device during a registration process. This can allow the authentication process to be encrypted using a shared secret generated based on the authentication server's public key. Using such a shared secret reduces the amount of computation resources used to perform encryption of communications compared to encrypting communications using an ephemeral key pair generated specifically for that communication.

FIG.7shows a message flow diagram700for secure authentication of a user device720using a registered user device authentication public key, in accordance with some embodiments. The message flow700shows messaging between the user device720, an authentication server740, and a provisioning server760. The user device720ofFIG.7may operate similar to the user devices described above. The authentication server740ofFIG.7may operate similar to the authentication servers described above. The provisioning server760ofFIG.7may operate similar to the provisioning servers described above. The messaging ofFIG.7may be performed in a different order or in another suitable manner. In addition, althoughFIG.7shows the messaging as being performed by the user device720, the authentication server740, and the provisioning server760, it should be noted some or all steps may be performed by another suitable entity. The authentication server740and the provisioning server760may perform certain operations instead of the other or the authentication server740and the provisioning server760may be combined.

Prior to message flow700, the user device720may store a user device attestation key pair (“UD Atts. Pub & Priv. Key Pair”)722including a user device attestation public key and a user device attestation private key corresponding to the user device attestation public key. The user device720may also store a user device attestation certificate (“UD Atts. Cert.”)724including the user device attestation public key. The user device620may also store a certificate authority certificate (“CA Cert.”)632including a CA public key.

Prior to message flow700, the provisioning server760may store a provisioning server key pair (“PS Pub. & Priv. Key Pair”)762including a provisioning server public key and a provisioning server private key corresponding to the provisioning server public key. The provisioning server760may also store a provisioning server certificate (“PS Cert.”)764that includes the provisioning server public key. The provisioning server certificate764may be signed by the certificate authority.

Prior to the message flow700, the authentication server740may store an authentication server certificate (“AS Cert.”)746, including an authentication server public key, that is signed by a CA. the authentication server640may also store an authentication server key pair (“AS Pub. & Priv. Key Pair)642including the authentication server public key and an authentication server private key corresponding to the authentication server public key. The authentication server740may also store the provisioning server certificate764.

The registration processes ofFIG.7may register an authentication public key of the user device720with the authentication server740. In addition, the registration process ofFIG.7may establish a registration shared secret between the user device720and the authentication server740, and registration may be conducted using a registration session key determined from the registration shared secret.

The user device720may generate a user device ephemeral key pair including a user device ephemeral public key and a user device ephemeral private key corresponding to the user device ephemeral public key. At701, user device720may send the user device ephemeral public key to authentication server740.

The authentication server740may generate an authentication server blinding factor (e.g., a cryptographic nonce) and combine the blinding factor with the authentication server key pair to generate a blinded authentication server public key and a blinded authentication server private key. The authentication server740may generate a registration shared secret using the user device ephemeral public key and the blinded authentication server private key. The authentication server740may use the registration shared secret to generate a registration session key. The authentication server740may encrypt the authentication server certificate744, the authentication server blinding factor, and a registration request using the registration shared secret to obtain, respectively, an encrypted authentication server certificate, an encrypted authentication server blinding factor, and an encrypted registration response. At702, the authentication server740may send the blinded authentication server public key, the encrypted authentication server certificate, and the encrypted registration request to the user device720. The authentication server740may also send an encrypted authentication cryptogram, encrypted meta-data, and the encrypted authentication server blinding factor to user device720.

The user device720may generate the same registration shared secret as generated by authentication server740using the blinded authentication server public key and the user device ephemeral private key. The user device720may generate the registration session key using the registration shared secret. The user device720may use the registration shared secret to decrypt the encrypted registration request to obtain the registration request. The user device720may also use the registration shared secret to decrypt the encrypted authentication server certificate744and the encrypted authentication server blinding factor to obtain the authentication server certificate744and the authentication server blinding factor, respectively. The user device720may verify the authentication server certificate744using the CA certificate732. The user device720may verify the blinded authentication server public key using the authentication server blinding factor an authentication server public key obtained from the authentication server certificate744.

The user device720may require authentication of a user of the user device720based on the registration request. To authenticate, the user may input authentication information into the user device720. For example, the user may input authentication information including at least one of a user identifier, a password, passcode, a PIN, a fingerprint scan, a retinal scan, or other biometric data. In response to authenticating the user, the user device720may generate a user device authentication key pair (UD Auth. Pub. & Priv. Key Pair”)726including a user device authentication public key728and a user device authentication private key corresponding to the user device authentication public key. The user device720may associate the input authentication information with the user device authentication key pair. The user device720may generate a user device authentication key pair (“UD Auth. Pub. & Priv. Key Pair”)726including a user device authentication public key728and a user device authentication private key corresponding to the user device authentication public key. The user device720may sign the user device authentication public key728using the user device attestation private key to obtain a signed user device authentication public key. The user device720may generate a registration response including the signed user device authentication public key, the user device attestation certificate, and an identifier. The identifier associated with the user device authentication public key. The user device720may encrypt the registration response using the registration shared secret.

At703, the user device720may send the encrypted registration response to authentication server740. In some embodiments, the registration response can be encrypted using the registration shared secret. In other embodiments, the user device720may generate a second registration shared secret for encrypting the registration response.

The authentication server740may decrypt the encrypted registration response using the registrations shared secret to obtain the registration response. The authentication server740may verify the user device attestation certificate724using a CA public key. The authentication server740may also verify the user device authentication public key728using the user device attestation public key of the user device attestation certificate724. The authentication server740may associate the user device authentication public key728with the identifier included in the registration response. The authentication server740may store the user device authentication public key728. In response to verifying the user device authentication public key728, the authentication server740may encrypt the provisioning server certificate764using the shared secret to obtain an encrypted provisioning server certificate. At704, the authentication server740may send the encrypted provisioning server certificate to the user device720. The user device720may decrypt the encrypted provisioning server certificate to obtain the provisioning server certificate764. The user device720may store the provisioning server certificate764.

As such, the user device720may confidentially register with the authentication server740and receive the provisioning server certificate. The user device720may use the provisioning server public key of the provisioning server certificate764and the user device authentication private key corresponding to the user device authentication public key, which was registered with the authentication server, to generate an authentication shared secret for encrypting the authentication process.

At705, the user device720may send the identifier to the authentication server740via the provisioning server760. The authentication server740may identify the user device authentication public key728associated with the identifier. The authentication server740may generate an authentication shared secret using the user device authentication public key728stored at the authentication server740and the authentication server private key corresponding to the authentication server public key. The authentication server740may generate an authentication request for the user device720. The authentication request may include an authentication challenge. The authentication server740may encrypt the authentication request using the authentication shared secret to obtain an encrypted authentication request. At706, the authentication server740may send the encrypted authentication request to the user device720.

The user device720may generate the authentication shared secret using the authentication server public key of the authentication server certificate744and the user device authentication private key corresponding to the user device authentication public key registered with the authentication server740. The user device720may decrypt the encrypted authentication request using the authentication shared secret to obtain the authentication request including the authentication challenge. The user device may process the authentication request. Processing the authentication request may include adding additional data to the received authentication challenge, verifying a user of user device720(e.g., by requiring the authentication information input at registration to be input by the user), and signing the authentication challenge in the authentication request using the user device authentication private key stored at the user device720. The user device720may generate an authentication response including the signed authentication challenge. The user device720may encrypt the authentication response using the authentication shared secret to obtain an encrypted authentication response. At707, the user device720may send the encrypted authentication response to the authentication server740via the provisioning server760.

The authentication server740may use the authentication shared secret to decrypt the encrypted authentication response to obtain the authentication response. The authentication server740may verify the signed challenge using the user device authentication public key728stored at the authentication server740during registration of the user device720. For example, the signed challenge may be verified by decrypted, using the user device authentication public key728, and it may be compared to the authentication challenge of the authentication request. If the signed authentication challenge matches an expected value, then the authentication server may authenticate the user device720. At708, the authentication server740may send an indication to the provisioning server760that the signed challenge has been verified.

If the signed challenge is authenticated, at709, the provisioning server760may send provisioning data to the user device720. The provisioning server may encrypt the provisioning data using the authentication shared secret.

As such, the user device authentication public key728that was registered with the authentication server740during registration may be used to generate an authentication shared secret for encryption of the authentication process. This provides advantages over generating an ephemeral key pair for encrypting authentication messages since generating and using a key pair is computationally intense and requires the use of a large amount of computing resources. Thus, encrypting the authentication request and authentication response using the registered user device authentication public key726may use less computing resources compared to a process that generates and uses an ephemeral key pair.

VI. Secure Communication Methods

Embodiments of the invention may utilize any suitable method for secure communication. For example, in some embodiments of the invention, methods in accordance with Opacity specifications can be used to facilitate secure communication between a user device, an authentication server, a provisioning server, and/or any other suitable entity. Table 1, below, includes definitions of terms.

TABLE 1ICCMobile phone, Integrated Circuit chip or serverIFDInterface device or clientenc_cEncrypted data generated on client (IFD/Mobile)enc_sEncrypted data generated on server (ICC)SD_cClient sensitive Data (payload)SD_sServer sensitive Data (payload)sID_sServer (ICC) identifier for the session. Based on Q_bs x_coordinatesID_cClient (IFD or mobile device) identifier. Truncated value of Q_ec's x_coordinateC_sCertificate Chain authenticating the Server (ICC)C_s_{n}Certificate Chain authenticating the Server (ICC)-nth versionC_cCertificate Chain authenticating the client (ICC)d_bcClient blinding factord_bsServer Blinding factorseedCounter or time, etc. verifiable at ICC or server and proving that blinding factoris fresh. d_bc = PRNG (seed)Q_bcBlinded Client public keyQ_bsBlinded server public keyd_c, Q_c = [d_c]PClient authentication public key, matched with the corresponding private key: d_cd_s, Q_s = [d_s]PServer (ICC) authentication public key, matched with the corresponding privatekey: d_sd_s_{n}, Q_s_{n}Server (ICC) authentication public and private key, nth version.d_ec, Q_ec = [d_ec]Pclient ephemeral public key, matched with the ephemeral private key: d_ecsk_1c, sk_c, sk_1s, sk_sAES Secure Messaging Session KeysZ, Z_1Intermediate Shared secrets (x-coordinate of EC-DH shared resulting point)AEAD, AEAD-1 (sk,Authenticated Encryption with Associated Data (AES session key SK, data willdata, associated data)be encrypted or decrypted. Associated data will remain as is, but controlled forintegrity.KDFKey Derivation Function 800-56C based on AES C_MAC. Applied onconcatenated inputPRNGPseudo random number generatorzero_keyAES key where all bytes have a zero value (see 800-56C)PubK (C)Extract the public key from Cert C
A. Methods Assuming a Pre-Loaded Server Certificate

A method for secure communication using a client computer that is pre-loaded with a server computer certificate is described below. The client computer may maintain data prior to the communication. For example, the client computer can maintain a number (n) server authentication public keys (Q_s_{n}) and server computer certificate chains (C_s_{n}). The client computer can also maintain client sensitive data (SD_c), which may include data usable by a server computer to authenticate the client computer. In addition, the client computer can maintain a client computer certificate chain (C_c) and a client authentication key pair including a client authentication public key (Q_c) and a corresponding client authentication private key (d_c). Furthermore, the client computer can maintain a seed value (seed) that is typically verifiable by the server computer.

The server computer may also maintain data prior to the communication. For example, the server computer can maintain a number (n) server computer certificate chains (C_s_{n}), each including a server authentication public key (Q_s_{n}) and the server computer maintaining a corresponding server authentication private key (d_s_{n}). The server computer can also maintain a next server authentication key pair including a next server authentication public key (Q_s_{n+1}) and a next server authentication private key (d_s_{n+1}). The server computer can also maintain an initialization value (IV) and server sensitive data (SD_s), which may include data usable by a client computer to authenticate the server computer.

At step 1, the client computer generates a client blinding factor (d_bc) using a PRNG function with the seed value as an input.

At step 2, the client computer generates a blinded client authentication public key (Q_bc) using the client blinding factor, an initialization value (d_iv), and the client authentication public key.

At step 3, the client computer generates a first shared secret (Z_1) using the client authentication public key, the client blinding factor, and the server authentication public key corresponding to the server computer for which communication is intended (Q_s_{n}).

At step 4, a client session identifier is generated using the blinded client authentication public key.

At step 5, a first client session key is derived using the first shared secret, a server identifier (ID_s), and the client session identifier.

At step 6, the first client session key is used to encrypt (AEAD) the client sensitive data, the client certificate chain, either the client blinding factor or the seed, some client padding data (PAD_c), and the blinded client authentication public key. The result is encrypted client data (enc_c).

At step 7, the first shared secret and the first client session key are zeroized (i.e., erased).

At step 8, the blinded client authentication public key ad the client encrypted data are sent to the server computer.

At step 9, the server computer validates that the blinded client authentication public key belongs to the correct elliptic curve domain.

At step 10, the server computer generates the same first shared secret, but using the server authentication private key, the initialization value, and the blinded client authentication public key.

At step 11, the server computer determines the client session identifier from the blinded client authentication public key.

At step 12, the server computer derives the first client session key using the first shared secret, the server identifier, and the client session identifier.

At step 13, the server computer decrypts (AEAD-1) the encrypted client data using the first client session key to obtain the client sensitive data, the client certificate chain, the client blinding factor or seed, and the client padding data.

At step 14, the server computer zeroizes the first client session key and the first shared secret.

At step 15, if the client blinding factor was not included in the encrypted client data decrypted at step 13, the server computer derives it from the seed using a PRNG function.

At step 16, the server computer extracts the client authentication public key from the client certificate. The client certificate is also validated.

At step 17, the blinded client authentication public key received from the client computer is compared to a combination of the client blinding factor and the client authentication public key. If they match, the server computer can authenticate the client computer.

At step 18, the server computer generates a server blinding factor (d_bs).

At step 19, a second shared secret (Z) is generated using the second blinding factor, the next server authentication private key, and the blinded client authentication public key.

At step 20, a blinded server authentication public key (Q_bs) is generated using the server authentication public key and the server blinding factor.

At step 21, a server session identifier (sID_s) is generated using the blinded server authentication public key.

At step 22, a server session key (sk_s) and a second client session key (sk_c) are generated using the second shared secret, the server session identifier, and the client session identifier.

At step 23, the server blinding factor, the next server certificate chain, the server sensitive data, and a server pad (PAD_s) are encrypted using the server session key to generate encrypted server data (enc_s).

At step 24, the server session key and the second shared secret are zeroized.

At step 25, the blinded server authentication public key and the encrypted server data are sent to the client computer.

At step 26, the client computer validates that the blinded server authentication public key belongs to the correct EC domain.

At step 27, the client computer determines the second shared secret using a combination of the client authentication private key and the client blinding factor, and the blinded server authentication public key.

At step 28, the client computer determines the server session identifier using the blinded server computer public key.

At step 29, the client computer derives the server session key and the second client session key using the second shared secret, the server session identifier, and the client session identifier.

At step 30, the client computer zeroizes the second session key and the client blinding factor.

At step 31, the client computer decrypts (AEAD-1) the encrypted server data using the server session key to obtain the server blinding factor, the next server certificate chain, the server sensitive data, and the server pad.

At step 32, the client computer extracts the next server authentication public key from the next server certificate chain.

At step 33, the client computer validates that the next server certificate chain belongs to the correct elliptic curve domain.

At step 34, the client computer validates that the combination of the next server authentication public key and the server blinding factor equals the blinded server authentication public key.

At step 35, the client computer and server computer can end communication or continue secure messaging using the second client session key and/or the server session key.

B. Methods Including Transfer of a Server Certificate

Another method for secure communication is described below. The method uses a client computer that may not be pre-loaded with a server computer certificate. The client computer may maintain data prior to the communication. For example, the client computer can maintain a client computer certificate chain (C_c) and a client authentication key pair including a client authentication public key (Q_c) and a corresponding client authentication private key (d_c).

The server computer may also maintain data prior to the communication. For example, the server computer can maintain a server computer certificate chain (C_s), including a server authentication public key (Q_s) and the server computer maintaining a corresponding server authentication private key (d_s). The server computer can also maintain server sensitive data (SD_s), which may include data usable by a client computer to authenticate the server computer.

At step 1, the client computer generates a client blinding factor (d_bc).

At step 2, the client computer combines the blinding factor with the client authentication public key to determine a blinded client authentication public key (Q_bc).

At step 3, the client computer determines a client session identifier (sID_c) using the blinded client authentication public key.

At step 4, the client computer sends the blinded client authentication public key to the server computer.

At step 5, the server computer ensures that the blinded client authentication public key belongs to the correct elliptic curve (EC) domain.

At step 6, the server computer generates a server blinding factor (d_bs).

At step 7, the server computer generates a shared secret (Z) using a combination of the server authentication private key and the server blinding factor, and the blinded client authentication public key.

At step 8, the server computer combines the server authentication public key and the server blinding factor to determine a blinded server authentication public key (Q_bs).

At step 9, the server computer determines a client session identifier (sID_c) using the blinded client authentication public key.

At step 10, the server computer determines a server session identifier (sID_s) using the blinded server authentication public key.

At step 11, the server computer generates a server session key and a client session key using the shared secret, the client session identifier, and the server session identifier.

At step 12, the server computer encrypts the server blinding factor, the server certificate chain, the server sensitive data, and a server pad (PAD_s) using the server session key to determine server encrypted data (enc_s).

At step 13, the server session key and the shared secret are zeroized.

At step 14, the blinded server authentication public key and the server encrypted data are sent to the client computer.

At step 15, the client computer validates that the blinded server authentication public key belongs to the correct EC domain.

At step 16, the client computer determines the shared secret using a combination of the client authentication private key and the client blinding factor, and the blinded server authentication public key.

At step 17, the client computer determines the server session identifier using the blinded server authentication public key.

At step 18, the client computer determines the server session key and the client session key using the shared secret, the server session identifier, and the client session identifier.

At step 19, the client computer zeroizes the shared secret and the client blinding factor.

At step 20, the client computer decrypts the server encrypted data using the server session key to obtain the server blinding factor, the server certificate chain, the server sensitive data, and the server pad.

At step 21, the client computer extracts the server authentication public key from the server certificate chain.

At step 22, the client computer validates that the server authentication public key belongs to the correct EC domain.

At step 23, the client computer verifies the server certificate chain.

At step 24, the client computer ensures that the combination of the server blinding factor and the server authentication public key is equal to the blinded server authentication public key received from the server computer.

At step 25, the server blinding factor is zeroized.

At step 26, if at step 24 the check is successful, the server computer is authenticated at the client computer.

At step 27, client encrypted data (enc_c) is generated by encrypting the client blinding factor, the client certificate chain, the client sensitive data, and a client pad (PAD_c) using the client session key.

At step 28, the client computer sends the client encrypted data to the server computer.

At step 29, the server computer decrypts the client encrypted data using the client session key to obtain the client blinding factor, the client certificate chain, the client sensitive data, and the client pad.

At step 30, the server computer extracts the client authentication public key from the client certificate chain and validates the client certificate chain.

At step 31, the server computer ensures that the combination of the client blinding factor and the client authentication public key matches the blinded client authentication public key received from the client computer. If they match, at step 33 the client computer is authenticated by the server computer.

At step 32, the client blinding factor is zeroized.

At step 34, the client computer and server computer can end communication or continue secure messaging using the second client session key and/or the server session key.

The above description is illustrative and is not restrictive. Many variations of the invention may become apparent to those skilled in the art upon review of the disclosure. The scope of the invention may, therefore, be determined not with reference to the above description, but instead may be determined with reference to the pending claims along with their full scope or equivalents.

It should be understood that any of the embodiments of the present invention can be implemented in the form of control logic using hardware (e.g. an application specific integrated circuit or field programmable gate array) and/or using computer software with a generally programmable processor in a modular or integrated manner. As used herein, a processor includes a single-core processor, multi-core processor on a same integrated chip, or multiple processing units on a single circuit board or networked. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will know and appreciate other ways and/or methods to implement embodiments of the present invention using hardware and a combination of hardware and software.

Any of the software components or functions described in this application may be implemented as software code to be executed by a processor using any suitable computer language such as, for example, Java, C, C++, C#, Objective-C, Swift, or scripting language such as Perl or Python using, for example, conventional or object-oriented techniques. The software code may be stored as a series of instructions or commands on a computer readable medium for storage and/or transmission. A suitable non-transitory computer readable medium can include random access memory (RAM), a read only memory (ROM), a magnetic medium such as a hard-drive or a floppy disk, or an optical medium such as a compact disk (CD) or DVD (digital versatile disk), flash memory, and the like. The computer readable medium may be any combination of such storage or transmission devices.

Storage media and computer-readable media for containing code, or portions of code, can include any appropriate media known or used in the art, including storage media and communication media, such as but not limited to volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage and/or transmission of information such as computer-readable instructions, data structures, program modules, or other data, including RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, data signals, data transmissions, or any other medium which can be used to store or transmit the desired information and which can be accessed by the computer. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will appreciate other ways and/or methods to implement the various embodiments.

Such programs may also be encoded and transmitted using carrier signals adapted for transmission via wired, optical, and/or wireless networks conforming to a variety of protocols, including the Internet. As such, a computer readable medium according to an embodiment of the present invention may be created using a data signal encoded with such programs. Computer readable media encoded with the program code may be packaged with a compatible device or provided separately from other devices (e.g., via Internet download). Any such computer readable medium may reside on or within a single computer product (e.g. a hard drive, a CD, or an entire computer system), and may be present on or within different computer products within a system or network. A computer system may include a monitor, printer, or other suitable display for providing any of the results mentioned herein to a user.

Any of the methods described herein may be totally or partially performed with a computer system including one or more processors, which can be configured to perform the steps. Thus, embodiments can be directed to computer systems configured to perform the steps of any of the methods described herein, potentially with different components performing a respective steps or a respective group of steps. Although presented as numbered steps, steps of methods herein can be performed at a same time or in a different order. Additionally, portions of these steps may be used with portions of other steps from other methods. Also, all or portions of a step may be optional. Additionally, any of the steps of any of the methods can be performed with modules, units, circuits, or other means for performing these steps.

The specific details of particular embodiments may be combined in any suitable manner without departing from the spirit and scope of embodiments of the invention. However, other embodiments of the invention may be directed to specific embodiments relating to each individual aspect, or specific combinations of these individual aspects.

The above description of example embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above.

A recitation of “a”, “an” or “the” is intended to mean “one or more” unless specifically indicated to the contrary. The use of “or” is intended to mean an “inclusive or,” and not an “exclusive or” unless specifically indicated to the contrary.

All patents, patent applications, publications, and descriptions mentioned herein are incorporated by reference in their entirety for all purposes. None is admitted to be prior art.