Signatures for near field communications

A data-carrying device and methods of authenticating the same are disclosed. The data-carrying device is described as being capable of communicating via the Near Field Communications (NFC) protocol and may have one or more NFC Data Exchange Format (NDEF) records stored in its memory. The data-carrying device also comprises or has the ability to generate a signature that proves the data-carrying device is the authorized device for storing the one or more NDEF records. A data-carrying device that attempts to transmit an NDEF record without a valid signature may be identified as an unauthorized data-carrying device.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. 371 of PCT Application No. PCT/IB2013/001949 having an international filing date of Jul. 1, 2013, which designated the United States, and which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure is generally directed toward creating and managing signatures for Near Field Communications (NFC) Data Exchange Format (NDEF) records.

BACKGROUND

One type of identification technology employs Near Field Communications (NFC). NFC is a set of short-range wireless communication technologies that have devices operate at approximately 13.56 MHz and at rates ranging from 106 kbit/s to 848 kbit/s. NFC standards cover communications protocols and data exchange formats, and are based on existing radio-frequency identification (RFID) standards including ISO/IEC 14443 and FeliCa, each of which are hereby incorporated herein by reference in their entirety. The standards include ISO/IEC 18092, which is also incorporated herein by reference in its entirety, and those defined by the NFC Forum.

Another type of technology currently gaining traction and emerging as a viable alternative to NFC is newer versions of the Bluetooth standard (e.g., Bluetooth 4), the entire contents of which are hereby incorporated herein by reference. Bluetooth is a wireless technology standard for exchanging data over short distances (using short-wavelength radio transmissions in the ISM band from 2400-2480 MHz) from fixed and mobile devices, creating personal area networks (PANs) with high levels of security. The primary difference between NFC technologies and Bluetooth technologies is that Bluetooth relies on powered devices for both sides of the communication whereas NFC facilitates communications between a powered device and a passive device (e.g., an NFC tag or credential). In other words, under NFC standards, one device can operate without an internal power source, such as a battery.

There are currently three NFC operating modes defined by the NFC Forum: (1) Card Emulation Mode; (2) Reader/Writer Mode; and (3) Peer-to-Peer Mode. In the Card Emulation Mode, an NFC-enabled phone emulates a contactless card in accordance with ISO 14443 and/or ISO 15693, each of which are hereby incorporated herein by reference in their entirety. Typical applications of the Card Emulation Mode include payment, ticketing, and access control applications.

In the Reader/Writer Mode, the NFC-enabled phone reads a tag and typically performs some function based on the information obtained from the read tag. Typical applications of the Reader/Writer Mode include reading posters with an NFC tag in proximity thereto, interactive advertising, launching mobile Internet (e.g., automated web-browser activation), automated Short Message Service (SMS), and automated call initiation.

In the Peer-to-Peer Mode, two NFC-enabled phones, or similar types of devices, are allowed to exchange data with one another. Typical applications of the Peer-to-Peer Mode include setting up wireless settings (e.g., Bluetooth, Wi-Fi, etc.), sharing business cards, or sharing information between NFC-enabled phones.

Current NFC tags carry NFC Data Exchange Format (NDEF) records, which have a static cryptographic signature to ensure the integrity of the data written to the tag. Unfortunately, this current approach has several weaknesses including clonability (moving the same data to another tag) and replay attacks (playing back the same static message again).

SUMMARY

It is one aspect of the present disclosure to solve the problem of moving valid data from one standard NFC tag to another. In particular, an NDEF record is disclosed that can be created with information about the tag itself including a non-random Unique Identifier (UID) (e.g., MAC address, SIM card number, tag ID, IP address, etc.). In some embodiments, this data can be included in the signature that is calculated for the NDEF record such that the verifier of the NDEF record could compare the record and UID read from the tag to validate the binding via the signature.

Another mechanism to prevent against cloning and replay attacks is disclosed whereby a dynamic signature (which can be based on a nonce sent by the reading device) can be calculated by the tag itself. Since this mechanism is independent of the tag UID, it allows for tags with random UIDs.

In some embodiments, to perform a challenge response authentication, a nonce can be provided to the tag, which is ultimately included in the signature calculation. This nonce could be provided in the request to read the tag data or during a separate authenticate command.

In some embodiments, the tag dynamic signature may be based on a Public Key Infrastructure (PKI) solution (e.g., RSA, ECDS, etc.) and hence also introduces the concept of a tag certificate. This certificate can be added into the standard NDEF security certificate chain so that the returned NDEF data containing the dynamic signature can be verified without any changes to the verification process of current standard NDEF specifications.

The tag certificate could include the unique identifier of the tag (e.g., static UID). The response signature might also return the tag certificate. The introduction of the tag certificate would also allow the concept of a Tag Revocation Service (e.g., a Tag Revocation List distributed and used to check the validity of tag certificates) or Online Certificate Status Protocol (OCSP) online services. Since a reading device might be desirable to check the revocation status of a tag (e.g., without performing authentication), embodiments of the present disclosure also contemplate a command or combination of commands that simply returns the tag certificate without performing any other processes.

The present disclosure will be further understood from the drawings and the following detailed description. Although this description sets forth specific details, it is understood that certain embodiments of the invention may be practiced without these specific details. It is also understood that in some instances, well-known circuits, components and techniques have not been shown in detail in order to avoid obscuring the understanding of the invention.

DETAILED DESCRIPTION

Referring initially toFIG. 1, a transaction system100is depicted in accordance with embodiments of the present disclosure. The transaction system100is shown to include a reading device104and a data-carrying device108. The reading device104and data-carrying device108may be configured to exchange data over a wireless communication path116using any type of known or yet to be developed wireless communication protocol. In some embodiments, the devices104,108may be configured to exchange data112with one another using an NFC protocol, a Bluetooth standard (e.g., Bluetooth 4), infrared, or the like. Where an NFC protocol is used, the data112may be stored as an NDEF record or collection of NDEF records.

It should also be appreciated that the communication path116does not necessarily have to be wireless. For instance, a wire or cable (e.g., Universal Serial Bus (USB) cable) may be used to carry data between the devices104,108.

In some embodiments, the reading device104and data-carrying device108may each be equipped with NFC interfaces that enable the devices104,108to exchange data in accordance with the NFC protocol. The devices104,108may exchange data using any type of NFC communication mode (e.g., a Card Emulation Mode, a Reader/Writer Mode, or a Peer-to-Peer Mode). When operating in the Card Emulation Mode, the data-carrying device108may emulate a card and the reading device104may correspond to a reader of the data-carrying device. When operating in the Reader/Writer Mode, the reading device104may write data to the data-carrying device108or the data-carrying device may write data to the reading device104.

In accordance with NFC standards, the devices104,108may only be allowed to communicate data with one another when the physical distance between the devices104,108is less than a predetermined distance. As an example, the devices104,108can be configured to exchange wireless communications with one another via NFC as long as the devices are close enough to support such communications (e.g., between approximately 0.01 m and 0.5 m). If Bluetooth is employed, then the mobile devices104,108may communicate with one another as long as the devices are between approximately 0.01 m and 2.0 m of one another. Of course, other protocols such as Wi-Fi, Zigbee, Wi-Max, and the like may be used to exchange data between devices104,108.

The data-carrying device108may correspond to any type of communication device such as a telephone, a mobile telephone, a cellular phone, a Personal Digital Assistant (PDA), a tablet, a thin client computing device, a netbook, a watch, a key fob, a portable card-shaped credential, or the like. Similarly, the reading device104may correspond to a telephone, a mobile telephone, a cellular phone, a PDA, a tablet, a thin client computing device, a netbook, a watch, a key fob, or the like. In some embodiments, the reading device104may correspond to a traditional access control reader that may or may not be mounted to a wall or permanent location. In still other embodiments, the reading device104may correspond to a mobile access control reader and/or writer.

As shown inFIG. 1, the data-carrying device108may have data112maintained thereon (e.g., stored in memory of the data-carrying device108). Although not depicted, the reading device104may also comprise data112stored thereon. In some embodiments, the data112may be used by the data-carrying device108to obtain access to one or more assets (e.g., logical and/or physical assets) protected by the reading device104. For instance, the data-carrying device108may provide some or all of the data112to the reading device104to access one or more assets protected by the reading device104.

In some embodiments, some or all of the data112may be stored in a secure area of memory, such as a Secure Element (SE), a Secure Access Module (SAM), a Subscriber Identity Module (SIM) card, an Integrated Circuit (IC) card, or any other computer memory that is encrypted and/or physically tamper-proof. As a non-limiting example, the data112may be stored as an NDEF record or collection of NDEF records along with one or more signatures that can validate the NDEF record or NDEF records. Specifically, NDEF records are a light-weight binary format, used to encapsulate typed data. NDEF records are specified by the NFC Forum, for transmission and storage with NFC, however, NDEF records are transport agnostic. In some embodiments, an NDEF record may include one or more of: typed data, such as MIME-type media, a URI, or a custom application payload. More specifically, an NDEF record may be configured to contain a 3-bit TNF (Type Name Field) that provides high level typing for the rest of the record. The remaining fields are variable length and not necessarily present: type—detailed typing for the payload; id—identifier meta-data; and/or payload—the actual payload.

With reference now toFIG. 2a method of generating a signature for an NDEF record will be described in accordance with at least some embodiments of the present disclosure. The method begins when it is determined that a new NDEF record is to be created and/or an NDEF record is to be updated (step204). Thereafter, the method continues by determining information about the device (e.g., data-carrying device108) on which the NDEF record will be stored (step208). In some embodiments, the determining step may include determining a UID, a site code, a card type, information about a user of the device, a hash value generated with one or a combination of such information, an XOR value generated with one or a combination of such information, some other non-random data, or some other value generated from non-random data.

The information determined in step208is then used to calculate a signature for the NDEF record (step212). In some embodiments, the signature generated for the NDEF record or collection of NDEF records is generated by combining the determined information with some or all of the NDEF record. As a non-limiting example, the determined information may be a hash value generated with a combination of the determined information and the NDEF record. In other embodiments, the signature can simply be generated by calculating a hash value with the determined information only. In other embodiments, the signature can simply correspond to a concantenation of the different information obtained in step208or a concantenation of the determined information with the NDEF record. It should be appreciated that the mechanism(s) used to generate the signature can vary without departing from the scope of the present disclosure.

Once the signature has been generated for the NDEF record, the signature is stored in the data-carrying device108along with the NDEF record (step216). In some embodiments, both the NDEF record and signature may be stored in a secure area of memory. In other embodiments, the NDEF record may be stored in a secure area of memory while the signature may be stored in a non-secure area of memory. In some embodiments, the signature can be used to validate the binding of the NDEF record with the device on which the NDEF record is stored. As an example, the reading device104can validate the data-carrying device108as being the intended (and possibly sole) keeper of the NDEF record because the NDEF record was bound with the data-carrying device108via the signature. The utilization of such a signature effectively prevents the unauthorized moving valid data112from an authorized data-carrying device108to an unauthorized data-carrying device.

Another mechanism that can be used to prevent cloning and/or replay attacks is to enable the data-carrying device108to generate a dynamic signature during an authentication process. With reference now toFIG. 3an authentication process will be described in accordance with at least some embodiments of the present disclosure. The method begins when either the reading device104or the data-carrying device108initiate an authentication process (step304). In some embodiments, the authentication process is initiated by the reading device104when the data-carrying device108is placed within a predetermined distance from the reading device104(e.g., within a read range of the reading device104).

The method continues with the reading device104providing the data-carrying device with a nonce value, for example (step308). While a nonce value may correspond to a random or pseudo-random number generated at the reading device104, a nonce word may be used instead of a nonce value. In other words, any arbitrary number or string may be provided to the data-carrying device108to perform the authentication process. It should also be noted that the nonce value can be provided in the request to read data from the data-carrying device108or it can be provided in a separate authenticate command (e.g., before or after the data112is read from the data-carrying device108).

Upon receiving the nonce value, the data-carrying device108may use the nonce value to generate a dynamic signature (step312). In some embodiments, the nonce value is brought within a secure element (SE) of the data-carrying device108and the signature is calculated within the SE. The dynamically-generated signature is then provided back to the reading device104(step316). It should be noted that since this mechanism can be independent of the data-carrying device108, this authentication protocol can be used for devices having random UIDs whereas the signature-creation process described inFIG. 2is suited for devices having non-random UIDs.

The method continues with the data-carrying device108providing one or more NDEF records to the reading device104(step320) and then the reading device104analyzing the NDEF record(s) and dynamically-generated signature (step324). Many variations may occur in the execution of steps308,312,316,320, and324. For example, the reading device104may first ask the data-carrying device108for one or more NDEF records and then ask the reading device104for a signature. The nonce value used by the data-carrying device108to generate the signature may be provided before or after the reading device104receives the NDEF records. As another example, the reading device104may first perform the authentication process (e.g., provide a nonce value to the data-carrying device and verify authenticity of the dynamic signature received back from the data-carrying device108) prior to obtaining an NDEF record from the data-carrying device108. As still another example, the signature and NDEF record may be provided at the same time and the reading device104may validate both the signature and NDEF record at the same time. As still another example, the data-carrying device108may be configured to embed the nonce in the NDEF record and dynamically generate a signature. Other variants of timing will become apparent to those of ordinary skill in the art and it should be appreciated that the claims are not confined by the illustrative examples described herein.

FIGS. 4 and 5depict two examples of the structure in which the data112may be stored on the data-carrying device108.FIG. 4depicts a data structure having four data fields: a first data field404for a first NDEF record that describes the information obtained in step208(e.g., tag data, tag UID, etc.); a second data field408for a second NDEF record that include the nonce value; a third data field412for the actual data to be analyzed by the reading device104; and a fourth data field416for the signature. As discussed above, the NDEF signature stored in the fourth data field416may be used to validate one of the other NDEF records stored in the data structure. Additionally or alternatively, the NDEF signature provides a validation that the NDEF records are used to validate the data-carrying device108. Specifically, the NDEF signature (whether dynamic or based on non-random data) can validate the binding between the NDEF record and the data-carrying device108that is intended or authorized to store the NDEF record.

FIG. 5depicts a data structure having three data fields: a first data field504for a first NDEF record that describes the information obtained in step208along with a nonce value (or some combination of the two values); a second data field508for the actual data to be analyzed by the reading device104; and a third data field512for the signature. The data structure depicted inFIG. 5may correspond to a compressed version of the data structure depicted inFIG. 4.

With reference now toFIG. 6, a certification method will be described in accordance with embodiments of the present disclosure. The method begins when the reading device104transmits a command to the data-carrying device for a tag certificate (step604). In response to receiving the command from the reading device104, the data-carrying device108generates and transmits a tag certificate to the reading device104(step608). In some embodiments, the tag certificate may correspond to a dynamically-generated signature, such as those described above. In some embodiments, the tag certificate may correspond to a public signature from a public-private key pair. The reading device104(or a certification agency in communication with the reading device104) may maintain the private key and the data-carrying device108may provide the public key corresponding to the private key in a key pair. In some embodiments, the tag certificate may have been added to the standard NDEF security certificate chain, so that an NDEF record containing the dynamic signature can be verified by the reading device104without any changes to the verification process defined in current NDEF specifications. In some embodiments, the tag certificate could include the non-random data (e.g., static UID). It should also be appreciated that the tag certificate could be provided to the reading device104during authentication (e.g., in step316or320).

Upon receiving the tag certificate, the reading device104may compare the tag certificate with a revocation list that has been provided or made available to the reading device104(step612). In other embodiments, the reading device104may provide the tag certificate to a third party for comparison with a revocation list. Based on the comparison of the tag certificate with the revocation list, the reading device104or some other device may determine and execute one or more actions or decide to perform no action (step616). As an example, if the tag certificate received from the data-carrying device108matches a tag certificate in a revocation list, then the reading device104or some other device may cause an alarm to be sounded, light one or more lights, the presenting data-carrying device108may be considered and treated as untrusted, security personnel may be notified, etc. More specifically, the tag revocation list may contain an identification of tag certificates that are either revoked or on hold. A tag certificate may be revoked irreversibly if it is discovered that the certificate authority improperly issued a certificate or if a private key is thought to be compromised. If this is the case, then the tag certificate may be added to the certificate revocation list. A tag certificate may also be considered temporarily invalid if the whereabouts of the certificate are unknown. The revocation list may also list these types of certificates that are currently being held. If a data-carrying device108presents a tag certificate that is listed on the revocation list, then actions consistent with identifying an untrusted data-carrying device108may be performed.

It should be appreciated that while embodiments of the present disclosure have been described in connection with a revocation list, the present disclosure is not so limited. For instance, a white list may be used instead of or in combination with a revocation list. Any other type of black or white listing processes may be performed in connection with the tag certificates, dynamic signatures, and static signatures described herein.