# Patent

## Title
Hardware-based zero-knowledge strong authentication (H0KSA)

## Abstract

Systems and methods are provided for a device to engage in a zero-knowledge proof with an entity requiring authentication either of secret material or of the device itself. The device may provide protection of the secret material or its private key for device authentication using a hardware security module (HSM) of the device, which may include, for example, a read-only memory (ROM) accessible or programmable only by the device manufacturer. In the case of authenticating the device itself a zero-knowledge proof of knowledge may be used. The zero-knowledge proof or zero-knowledge proof of knowledge may be conducted via a communication channel on which an end-to-end (e.g., the device at one end and entity requiring authentication at the other end) unbroken chain of trust is established, unbroken chain of trust referring to a communication channel for which endpoints of each link in the communication channel mutually authenticate each other prior to conducting the zero-knowledge proof of knowledge and for which each link of the communication channel is protected by at least one of hardware protection and encryption.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 12/732,168, filed Mar. 25, 2010, which is a continuation-in-part of U.S. patent application Ser. No. 12/643,972, filed Dec. 21, 2009, which claims the benefit of priority of U.S. Provisional Application No. 61/182,623, filed May 29, 2009, all of which are hereby incorporated by reference.


BACKGROUND
1. Technical Field
Embodiments of the present invention generally relate to secure financial transactions initiated from an electronic device and, more particularly, to the ability to use the phone function (e.g., of a mobile handset) to feed data back to a Trusted Integrity Manager as part of a Mobile Embedded Payment program in the financial industry to authenticate users (e.g., a consumer).
2. Related Art
In direct (face-to-face) or online financial transactions customers may search for and purchase products and/or services from a merchant. In the case of online shopping, transactions are conducted through electronic communications with online merchants over electronic networks. A variety of electronic devices and various electronic techniques may be used to conduct such electronic transactions. Methods of initiating or making financial transactions from an electronic device include, for example, SMS (Short Message Service), radio frequency identification (RFID) or near field communication (NFC) at a point-of-sale (POS), and mobile Internet-based payments, by which customers search for and purchase products and services through electronic communications with online merchants over electronic networks such as the Internet. Such electronic transactions may be conducted via wireless communication, also referred to as “over-the-air” (OTA) communication—which may include ordinary (e.g., longer distance) radio frequency (RF) communication; mid-range communication such as Wi-Fi or Bluetooth; or short-range RFID or NFC, for communication over a distance that is typically less than about 4 inches). Such transactions may be conducted, for example, with a cell phone using the cell phone's normal RF communication or using NFC if the cell phone is NFC-enabled. Other mobile devices, in addition to cell phones, that may provide OTA communication for facilitating such transactions may include, for example, radio frequency-enabled credit and debit cards, key fobs, mobile Internet devices, consumer electronics (not limited to, but as an example, a contactless and proximity enabled personal computer or laptop) and contactless and proximity enabled personal digital assistants (PDA).
When registering a mobile device or conducting a financial transaction via any kind of consumer electronic device (CED), security is generally an issue in that data transferred wirelessly may typically include credit card and financial instrument information such as a user name, account number, a PIN, and a password, for example, that are susceptible to theft or malicious attack. In addition, a number of parties may be involved in the transaction including, for example, a customer or user, a merchant, a mobile network operator (MNO), a service provider (SP), a trusted service manager (TSM), a mobile phone manufacturer, an integrated chip (IC) manufacturer, and application (software) developers. Another central issue with consumer electronic devices—such as a personal computer (PC), a laptop, mobile phone, NFC enabled mobile device, for example, or other CEDs—is the need for cooperation between the many involved parties, in addition to financial institutions, to meet the needs of the customer via a secure over-the-air link.
SUMMARY
According to one or more embodiments of the present invention, a mobile embedded payment (MEP) system operated, for example, by a financial service provider (FSP) in the financial industry includes a Trusted Integrity Manager (TIM)—which may also be referred to as a Trusted Authentication Provider (TAP)—as part of, or functioning in conjunction with, a Trusted Service Manager (TSM). TIM enables the ability to use the phone function of a mobile handheld device to feed data (including, e.g., time and geo-location) back to the TIM to authenticate users in the context, for example, of financial transactions. TIM works with TSM, which may be loosely described as a primitive key management system. TIM provides additional security, especially with payment applications. TIM includes many different sub-systems, and modules and components within the sub-systems. TIM works with the TSM to provide additional security between entities (e.g., mobile device, payment provider, financial institution) in secure transactions.
In one embodiment, TIM is added to a TSM that manages financial-related communication between carriers, consumers, retailers, and financial institutions. Conventional TSM has only a Trusted Service Provider (TSP) and a Trusted Third Party (TTP) component. TSP functions include select and validate, manage, and monetize applications. TTP functions include SIM (Subscriber Identity Module) issuing, OTA personalization, and life cycle management of the hardware (e.g., for SIM software). The functions of the TIM include performing various service processes which may include, for example, validating, provisioning via TTP, authorizing, and re-issuing various pieces of information inside a mobile device (also referred to as mobile handset but not limited only to handsets) of a consumer or user. The TIM also manages and makes sure the data for validation of a transaction are handled securely from a remote location (TSM in itself may be like a large central remote processor of electronic data, payment or non payment). By coupling the TIM function, acting as a server in a conventional client-server architecture, in the TSM and an embedded secure element (eSE) acting as a client—implementations of various embodiments may rely, for example, on eSE, Secure Memory Card, or Universal Integrated Circuit Card (UICC)—inside the handset, a new level of verification and security is added.
Initially, the TTP provides a SIM key(s) to a carrier. The carrier then activates the service with a user when a user purchases a handset and the service. This is a usual activation. Through an application (also referred to as “app”) on the handset—which may be purchased and downloaded, for example, via an application store such as App StoreTM, a trademark of Apple, Inc.—the user requests enablement of payment functions on his or her handset. In order to achieve a higher level of security, a payment secure element, SE, embedded with the RF chip (or working in conjunction with the RF chip) serves as a repository of all financial critical data inside the handset. The application downloaded is to be verified by the TSM/TSP prior to being downloaded. When downloaded over the air (OTA), the application is installed in the proper SE and memory area by the TTP. Additionally a logical switch is activated to turn on the payment SE and link it to the SIM for User/IMEI (International Mobile Equipment Identification) parameters binding. Data for validation is to be sent back to the TIM to create a profile. The mobile device becomes effectively a payment device with security parameters stronger than existing models. The payment engine is contained in the embedded SE, while non-critical or properly authorized applications reside in the SIM card.
A second step—e.g., after provisioning of a SIM card and enablement of payment functions, at which juncture the SIM card is then referred to as the “provisioning SIM”—is provisioning of a payment instrument. The user requests his/her payment card to be installed on the phone, i.e., handset or device. Since the device is mobile, the original request goes to the TSP (which can be through a specific bank wallet for example). The TSP then requests validation, verification, and authorization that the specific instrument that has been requested is a legitimate instrument for that user. When the authorization from the bank is received by the TSM, the information is sent to the TIM to be validated and packaged in the proper format for the handset and to be understood by the embedded SE payment engine, e.g., a Mobile Embedded Payment (MEP) client.
The TIM then passes the “package” to be installed into the embedded SE to the TTP who will OTA install the “package” on the handset. At no time is the TTP aware of the encryption or keys used. Within the payment engine, e.g., embedded SE, all the payment instruments are to be validated by the TIM to be executed on the handset, and their integrity is to be checked on a regular basis against the TIM knowledge. Furthermore, some data linked to the user and handset could be used by the TIM to verify identity or authorization credentials on transactions in a regular acquiring process that is beyond what is done in the prior art. This includes, but not limited to, feeding back time and geo-location data from the device to the TIM to cross reference merchant ID (strong non-repudiation), user ID (strong user protection) and device ID (strong integrity of payment instruments used for banks) as well as location and time of a transaction. Geo-location could be important for user protection to make sure the user and device binding known by the TIM does match with the merchant acceptance device (known location in financial network) and the handset used for the payment (e.g., same city, same country).
In another embodiment, a consumer electronic device—for example but not limited to: a personal computer (PC), a laptop, a mobile phone, an NFC-enabled mobile device, a NetTop or NetTV—determines whether a proper SIM card (or UICC, for example, or other uniquely identifiable available network communication element appropriate to the device) is present, whether a connection to the mobile network operator is present, whether data has been changed in the device's embedded SE, and whether an actual SIM card is present. Based on these conditions, the user is allowed, e.g., by a Trusted Remote Attestation Agent (TRAA), specific use of the device for NFC payments, for example, or other OTA or wirelessly conducted transactions. More specifically, for example, an NFC-enabled mobile device may have TRAA software running on an embedded SE in the device. The embedded SE is in communication with the device SIM card. The TRAA software runs to check whether data in the secure element has been changed. If so, and there has been no confirmation from the TSM or TIM through the mobile network, the device is locked and cannot be used until confirmation of the change can be made, such as through the TSM or a call to the FSP. TRAA also checks whether the SIM card present is actually the SIM card used to provision the phone (the provisioning SIM), such as by matching the SIM card unique ID with what is expected. If the SIM card is not the provisioning SIM or if a SIM card is not present, the device is held until the provisioning SIM is available. The TRAA also checks whether there is a connection to the network and TSM. Such a situation may arise, for example, when the device is in a foreign country, underground, or in a tunnel. If the provisioning SIM is not available, a predetermined transaction cap is imposed, such as $50, and transactions more than the predetermined transaction cap (or a total amount) are denied until the network becomes available again for communication with the TSM. This conditional denial reduces risk of fraudulent purchases.
In one embodiment a system includes: a device including a hardware security module (HSM) in which the HSM protects a secret material so that the secret material is inaccessible by unauthenticated and unintended entities and the HSM communicates via a protected communication channel with an entity; and the device is configured to engage in a zero-knowledge proof with the entity via the communication channel to authenticate the secret material. In another embodiment, a method includes: protecting a secret material in a hardware security module of a device; establishing an end-to-end chain of trust over a communication channel, in which: the channel has two endpoints, the hardware security module being at one of a first endpoint and a second endpoint; and an unbroken chain of trust is established between the first endpoint and the second endpoint of the channel; and authenticating the secret material in which the first endpoint and second endpoint engage in a zero-knowledge proof via the communication channel to authenticate the secret material. In another embodiment, a method includes: protecting a private key in a secure vault of a device; and using a zero-knowledge proof of knowledge with the private key as proof material to authenticate the device so that the private key remains private to the device.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a system diagram illustrating an ecosystem for financial transactions using a mobile phone function in accordance with an embodiment of the present invention.
FIG. 2 is a system diagram illustrating a portion of the ecosystem of FIG. 1 relative to a Trusted Service Manager (TSM) in accordance with an embodiment.
FIG. 3 is a system block diagram illustrating TSM components in accordance with an embodiment.
FIG. 4A is a functional block diagram illustrating an example of system level functions of a Trusted Integrity Manager (TIM) in accordance with an embodiment.
FIG. 4B is a system block diagram illustrating an example of TIM subsystems and organization in accordance with an embodiment.
FIG. 5 is a system diagram illustrating a first example of TSM and TIM locations in an ecosystem for financial transactions in accordance with an embodiment.
FIG. 6 is a system diagram illustrating a second example of TSM and TIM locations in an ecosystem for financial transactions in accordance with an embodiment.
FIG. 7 is a system diagram illustrating a third example of TSM and TIM locations in an ecosystem for financial transactions in accordance with an embodiment.
FIG. 8 is a system diagram illustrating payment and application flows in an ecosystem for financial transactions in accordance with one or more embodiments.
FIG. 9 is a process flow and interaction diagram illustrating system interactions for an ecosystem for financial transactions using a mobile phone function in accordance with an embodiment.
FIG. 10 is a sequence of user interface displays illustrating an example of a “one-touch-one-tap” payment process in accordance with an embodiment.
FIG. 11 is an entity-relationship diagram illustrating secure identity binding (SIB) in accordance with an embodiment.
FIG. 12 is a system block diagram illustrating an example of hardware-based zero-knowledge strong authentication (H0KSA) according to one embodiment.
FIG. 12A is a flowchart diagram illustrating a method for hardware-based zero-knowledge strong authentication according to an embodiment.
FIG. 13 is an entity-relationship diagram illustrating trusted remote attestation agent (TRAA) system level operational relationships in accordance with an embodiment.
FIG. 14 is an example of an interactive phishing detection (IPD) visual indicator in accordance with an embodiment.



DETAILED DESCRIPTION
Embodiments of the present invention relate to mobile embedded payment (MEP) systems and methods for providing secure financial transactions over a network using a Trusted Service Manager. In one embodiment, a Trusted Integrity Manager (TIM)—which may also be referred to as a Trusted Authentication Provider (TAP)—is provided in addition to a Trusted Service Manager (TSM) that manages financial-related communication between carriers, consumers, retailers, and financial institutions. The TIM (acting, e.g., as MEP system server and providing various service processes) and the ability to use the phone function (acting, e.g., as MEP client) to feed data back to the TIM are novel concepts in the financial industry. By coupling the TIM server functions to an embedded secure element (eSE) client inside the handset, a new level of verification and security may be introduced into the financial industry.
The functioning of the TIM may be considered the “trust foundation” of the TSM and enables a financial service provider (FSP)—such as PayPal, Inc.—to provide provisioning services but also to operate an authentication service. TIM provides key pieces, for example, of the “remote” communications involved in using near-field communications (NFC) and other wireless or OTA communications for transactions, enabling applications to be trusted, and removal of liability associated with trusted application execution on user handsets, by strongly binding the user, the account and payment instrument, the value instrument, e.g., coupon or ticket, and the device to a central trusted and liable back-end entity. Another function of the TIM is similar to a key management authority (KMA) or controlling authority (CA).
The MEP system may include a back-end infrastructure and various business services. For example, one business service may include an on-card fingerprint authentication that operates using a fingerprint digital image stored or processed in the eSE vault of the FSP. The eSE vault may be located on the user's mobile handset, for example. A specific cryptographic authentication protocol may be used to make sure the “live reading” (e.g., real-time processing) of the fingerprint is properly matched with a tagged stored image on the chip, e.g., IC chip used to implement the eSE. The processing includes a dual real-time matching that is novel compared to the way on-chip fingerprint authentication is typically performed.
Also, for example, another business service may include an authentication service that incorporates the possibility of leveraging geo-location information from the handset, fingerprint strong authentication, device marking, timestamp, and other types of data that may be considered raw data. Some of these types of data may be provided, for example, by the carrier (e.g., mobile network operator). The batch of raw data may be used to provide an additional tool of risk assessment to issuing banks in addition to the usual transaction data the issuing banks received via the acquiring network. From the batch of data, the FSP may control the level of risk to be tolerated and fine tune the risk associated with the use, for example, of the NFC-enabled mobile phone or other wireless or OTA-communicating devices.
For example, if the phone is offline, the FSP could implement a parameter in the eSE to limit spending to a pre-determined dollar amount per day before requiring a forced (e.g., mandatory or prerequisite to further spending) access to the network. The parameter may also allow having a counter-reset in the eSE in compliance with EMV requirements (EMV is a standard for interoperation of IC chip cards, the letters EMV being taken from Europay-Mastercard-Visa). This capacity to work offline may be enabled by profiling of user, device, and transaction. Having a smart counter associated with the MEP client may allow managing of various parameters to authorize or decline a transaction without going back to the FSP cloud (see, e.g., FIG. 5). Such parameters may include, for example, a cash reserve, preset, or prepaid dollar amount on the user mobile device linked to the back-end FSP balance (but not allowed to exceed the balance); a number of transactions authorized; or a dollar amount limit—such as $100 a day with a request to connect back to the FSP cloud, when getting close to the limit, for verification and updating of the profile parameters. The smart counter may also include the capacity to keep a history log of the offline transactions to update the FSP cloud when connecting back.
Returning to the raw data provided for the authentication service, if the user desires to skip the fingerprint, the FSP could, for example, attach a higher risk to the transaction or require the input of a fingerprint for transactions above a certain threshold related to the parameters. In the case, for example, of P2P (point-to-point) NFC for classified transactions, the authentication service may allow the FSP to send over the air (OTA) a pre-verified certificate both for the vendor and the buyer, providing a cashless transaction with trusted payment. At the same time the buyer provides the pre-paid certificate to the seller, the seller will be informed that payment was completed and the buyer will receive a certificate from the seller that indeed the payment was received and the goods released. In that instance, the FSP may provide real-time micro escrow for both parties.
FIG. 1 is a system diagram illustrating an ecosystem 100 for financial transactions using a mobile phone function. FIG. 1 shows a variance of the traditional “4-corners model” adapted to reflect the specificities of the mobile ecosystem 100. FIG. 1 shows information and monetary or credit flows 101, 103, 105, 107, 109, 111 that may take place between various entities (e.g., 102, 104) in support of or in consequence of a financial transaction between a consumer 102 and a merchant 104 in the case that an issuer 106 (e.g., credit card company or bank) and an acquirer 108 (e.g., a part of a bank that receives and pays out funds as opposed to the part that issues credit, the issuer) are involved. As shown in FIG. 1, flows 103, 105, 111, 113 between merchant 104 and acquirer 108 may involve communications and transactions flowing through networks 110 and banks 112. Similarly, as seen in FIG. 1, flows 115, 117, 119, 121 between consumer 102 and issuer 106 may involve communications and transactions flowing through networks 110, banks 112, and financial institutions (FI) 114. When additional functionality for using a mobile handset 116 to facilitate a transaction is provided in accordance with one or more embodiments of the present invention, however, flows 115, 117, 119, 121 between consumer 102 and issuer 106 may involve communications and transactions that involve additional entities. Examples of such additional entities, as seen in FIG. 1, include mobile network operators (MNO) 118, manufacturers of integrated circuit chips (Chip) 120, manufacturers and providers of mobile handsets (Handset) 122, and trusted service managers (TSM) 124 as defined by the GSMA (Global System for Mobile Association). Thus, there is a need to coordinate various security and trusted management functions among the entities involved, including the additional entities.
FIG. 2 is a system diagram illustrating a portion 200 of the ecosystem 100 of FIG. 1 relative to a Trusted Service Manager 124. FIG. 2 is illustrative of the variety of entities that a TSM 124 may interface with and perform services related to. As seen in FIG. 2, there may be many parties in the ecosystem 100. For purposes of security and secure communications, it may be assumed that none trusts (nor should trust) the others. Many of the TSM functions may be defined by integrated circuit chip vendors 220 (e.g., providers of integrated circuits for handsets and reading devices) and mobile carriers (e.g., mobile network operators 118). Services provided by such functions may be low level in the sense that the services relate more to functioning of the hardware than facilitation of financial transactions. Thus, one or more embodiments may provide functions and services additional to those provided by a TSM 124. Such services may relate, for example, to security, trust management, and shifting of liability.
FIG. 3 is a system block diagram illustrating some components of a TSM, e.g., TSM 124. Trusted Third Party (TTP) 302 may only manage the physical aspects of the secure element (SE, see, e.g., FIGS. 4B, 5) such as key management authority (KMA), memory allocation, pre- or post-provisioning, and OTA conduits, for example. Thus, for example, TTP 302 may provide a physical SD (Secure Domain; a secure memory card such as a TrustedFlash card) controlling authority 304 and physical key management 306.
Trusted Service Provider (TSP) 312 may only manage SE-related services such as validation, service authentication, and application execution on or from the SE. For example, TSP 312 may provide an application authentication 314 service and a service enrollment portal 316.
FIG. 4A is a functional block diagram illustrating an example of functions that may be performed by a trusted integrity manager (TIM) 400 as part of a mobile embedded payment (MEP) system. TIM 400 may provide liability management 401 in addition with other services including system risk management 402, device risk management 403, and user risk management 404. System risk management 402 may include, for example, strong authentication 4021, system security 4022, and system policy 4023 (with regard to information security, also referred to as InfoSec). Device risk management 403 may include, for example, device ID verification 4031, device management 4032, and device policy 4033 (with regard to InfoSec). User risk management 404 may include user identification 4041, user authentication 4042, and user policy 4043 (with regard to InfoSec).
FIG. 4B is a system block diagram illustrating an example of TIM 400 subsystems and organization. As shown in FIG. 4B, TIM 400 may include a number of modules 410 through 490 for performing various functions and service processes. A service process may be any process which facilitates performing a service, and may include, for example, processes that facilitate performing the functions described with reference to FIG. 4A. TIM 400 may include, for example, modules for profile management 410, provisioning 420, console 430, authentication 440, cryptography 450, device interrogation 460, device management 470, communication 480, and connector 490.
The module for profile management 410 may include device profiles 4101 including, as seen in FIG. 4B, sets of profiles 4103 for mobile phones, televisions, set top boxes, NetTops, game consoles, and other devices—such as NetTVs. The module for profile management 410 may also include risk profiles 4102 including, as seen in FIG. 4B, a group of profiles for users 4104, a group of profiles for devices 4105, and a group of profiles for systems 4106. Provisioning module 420 may include modules 4202 for pre-provisioning, post-provisioning, onboard, and move. Console module 430 may include modules 4302 for operations (ops), logging, monitoring, tracing. Authentication module 440 may include modules 4402 for hardware-based zero knowledge strong authentication (H0KSA), behavior, password (PWD), and biometric authentication. Cryptography module 450 (denoted “crypto” in FIG. 4B) may include modules 4502 for a suite of algorithms, oblivious hashing (OH), verification, and key management. Device interrogation module 460 may include modules 4602 for interrogation of SIM (Subscriber Identity Modules or SIM cards), eSE (embedded secure elements), application identifiers, developer identifiers, TPM/MPM trusted platform module (TPM), mobile trusted module (MTM), GPS (global positioning system), platform identifiers, and stack identifiers. Device management 470 module may include modules 4702 for SRUM, SIB (secure identity binding), TRAA (trusted remote attestation agent), wipe/lock, and delegate, and module 4704 for IPD (interactive phishing detection). Communication module 480 may include modules 4802 for internet protocols (TCP/IP), telecom protocol, Near Field Communication/Bluetooth (NFC/BT), and secure SMS (short message service). Connector module 490 may include modules 4902 for Trinity/IAF (International Accreditation Forum, Inc.), AP (authentication provision), risk, and TSM (trusted service manager).
FIG. 5 is a system diagram—which may also be described as a bank centric model—illustrating a first example of TSM 124 and TIM 400 locations in a mobile embedded payment (MEP) system 500 for financial transactions. As shown in FIG. 5, TIM 400 functions may be included in an FSP (financial service provider) cloud 502 with functions performed by the TSM 124. Thus, the TIM 400 and TSM 124 functions may both be provided by a single service provider, e.g., FSP 504. FIG. 5 also shows other features and elements that may be included in MEP system 500. MEP system 500 may include a mobile phone handset 510 (shown as “mobile terminal” in FIG. 5). Mobile device 510 may include a provisioning SIM card 512 and an eSE 514 (embedded secure element). A secure communication link 513 inside mobile device 510 may connect provisioning SIM card 512 and eSE 514. Mobile device 510 may ordinarily communicate via link 515 through MNO cloud 506 with the outside world. Provisioning SIM card 512 may also connect over link 517 with TIM 400. Mobile network operator (MNO) 508 may communicate with TSM 124 and TIM 400 via link 519.
FIG. 6 is a system diagram illustrating a second example—which may also be described as a delegate or shared management model—of TSM 124 and TIM 400 locations in a mobile embedded payment (MEP) system 600 for financial transactions. As shown in FIG. 6, TIM 400 functions may be performed by a service provider, e.g., FSP 504 in FSP cloud 602, independently of a provider of TSM 124 functions. In the example shown in FIG. 6, TSM 124 functions may be performed by an MNO 508 or a third party operating in conjunction with an MNO 508 in the MNO cloud 606. MEP system 600 may include a mobile device 510 connected via link 515 to MNO 508. MNO 508 may communicate with TSM 124 via link 619. TSM 124 may communicate with TIM 400 via link 621. A provisioning SIM card 512 of mobile device 510 may also connect over link 517 with TIM 400.
FIG. 7 is a system diagram illustrating a third example—which may also be described as a carrier centric model—of TSM 124 and TIM 400 locations in a mobile embedded payment (MEP) system 700 for financial transactions. As shown in FIG. 7, TIM 400 functions may be included with functions performed by a TSM 124 and the TIM 400 and TSM 124 functions may both be provided by an MNO 508 or a third party operating in conjunction with an MNO 508 in the MNO cloud 706 independently of a financial service provider, e.g., FSP 504 in FSP cloud 702.
In the example shown in FIG. 7, MEP system 700 may include a mobile device 510 connected via link 515 to MNO 508. MNO 508 may communicate with TSM 124 and TIM 400 via link 719. TSM 124 and TIM 400 may communicate with FSP 504 via link 721. An eSE 514 of mobile device 510 may also connect over link 517 with FSP 504.
FIG. 8 is a system diagram illustrating payment and application flows in an MEP system 800 for financial transactions. FIG. 8 is similar to FIG. 1 and provides a more detailed illustration of payment and application flows. Although, FIG. 8 shows TIM 400 included as part of a TSM 124, FIG. 8 is applicable to the configurations shown in FIGS. 5, 6, and 7.
FIG. 9 is a process flow and interaction diagram illustrating system interactions for an MEP system—such as MEP system 500, 600, 700, or 800—for financial transactions using a mobile phone function. FIG. 9 shows interactions and flows among the entities listed horizontally across the top of the diagram, which are: Users, Carrier (e.g., an MNO), TSM/TSP (which may be operated by FSP), TTP, TIM (which may be operated by the FSP), and Bank (e.g., bank, credit card company, or other financial institution). Also listed at the top of FIG. 9 is a column labeled “Flow” which describes the type of item involved in an interaction between two entities as a sequence of events is traversed by moving vertically down the diagram.
Groups of arrows in the diagram illustrate various events. So, for example, the first event illustrated at the top of the diagram of FIG. 9 may be the supplying of SIM keys (“SIM keys” shown in the “Flow” column) from the TTP to the Carrier (indicated by the arrow 902 from TTP to Carrier). After an initial purchase of handsets and services (second entry in “Flow” column), the Carrier may activate service and a SIM card ID (third entry in “Flow” column) for a user, as indicated by the arrow 904 from Carrier to Users.
The next group of arrows (beginning with arrow 906 from Users to TSM/TSP) indicates that a user may request the handset to be payment enabled, which may involve the purchase of an app from TSM/TSP (arrow 906), as described above, authentication and validation of the app by the TIM (arrow 908), packaging by the TIM, and providing the app information to the TTP (arrow 910) for OTA installation (arrow 912) in a secure element (SE) of the handset, also as described above.
Provisioning of the handset, as described above, with a payment instrument (e.g., credit card, debit card, pre-paid card, or gift card) is also illustrated by the bottom set of arrows in FIG. 9, beginning with arrow 914, representing request for provisioning by the user to the TSM/TSP. The request may be forwarded to a bank (arrow 916), which may approve funding (arrow 918), e.g., from a user bank account. TSM/TSP may notify TIM that funding for the payment instrument is available (arrow 920), which may be forwarded to the TTP (arrow 922) and OTA installation of the payment instrument on the mobile device may be provided by the TTP (arrow 924).
The user experience (also referred to by the FSP as “front end flow”) with regard to provisioning may described as follows: prior to using the payment instrument on the handset, the user will download (from an application store, for example), or launch, the pre-installed application of the FSP from the handset. The request to launch, the application of the FSP can come from the user or can be instigated by the carrier (e.g., MNO) or the bank upon enrollment of the handset to become a payment instrument. The application, also referred to as “Mobile Embedded Payment client” may be installed in the eSE (embedded secure element) and may also be referred to as FSP payment engine, FSP payment vault, and FSP application.
When the FSP application is installed in the eSE, the FSP becomes de-facto controlling authority and takes ownership of the Issuing Domain on the eSE in accordance with industry accepted technology (including, for example, Global Platform specifications). This is one of the TIM 400 functions in the background. The physical OTA function may be performed by a TTP/OTA partner. This requires a pre-provisioning that can be managed by silicon vendors or a post-provisioning, OTA mechanism to be put in place. There are, for example, known procedures that are already used in the industry at production or post-production time.
When the application is installed and the handset becomes trusted, and if no payment instruments were pre-packaged with the FSP application, the user can request the installation of new or additional payment instruments. These must be installed in the eSE if using the full FSP payment engine. However, in some cases, banks will want to maintain more control and may request to have their application and instrument residing on the UICC/SIM of the mobile device (e.g., mobile device 510) to still leverage the FSP payment engine of another FSP. In that case, the FSP application will need to contain the proper credential to be authenticated and authorized to be executed via the FSP payment engine.
FIG. 10 is a sequence of user interface displays illustrating an example of a “one-touch-one-tap” payment process in accordance with an embodiment. The user experience with regard to using the phone for payment may described as follows: the user will launch the FSP “wallet” or the portion of the FSP application (client) not residing on the eSE from the user interface or by linking, or enrolling, the FSP application to the fingerprint (FP) reader. At interface displays 1001 to 1005, the user will slide the user's finger across the FP reader and the user's default FSP payment instrument will be launched. If no change is required, the user will tap his phone and proceed. In these example displays, interface display 1001 shows a progress bar that animates right to left and begins to move up to reveal the user's fingerprint that has been touched to the FP reader. In interface displays 1002, 1003, 1004, and 1005, the progress bar moves to the top of the display revealing more of the fingerprint as the progress bar moves, and the display of the fingerprint may darken as the scan of the progress bar moves to the top of the display. At interface display 1011, the progress bar may change to a top banner indicating, for example, “Ready to Pay”. At interface displays 1012, 1013, 1014, and 1015, an image of a funding card, e.g., the default funding card, animates to the top of the display, and buttons, e.g., “Cancel” and “Change”, appear once the funding card reaches its final position. At this point, for example, an option to change the funding source may be given to the user and then the user may need to go through one more display screen (e.g., interface displays 1011 to 1015 over again) to pick up the desired funding source. Interface displays 1021 to 1025 show an example display for the user once a payment has been made using the mobile device, e.g., mobile device 510. At interface display 1021, the “Ready to Pay” banner may change to an animated “Processing” banner. At interface displays 1021, 1022, and 1023, the funding card image may fade away as a receipt for purchase comes into view. At interface display 1025, once the funding card image is off screen, purchase details and a “Done” button may appear on the display, and the user may be given an option to terminate the display. When the payment is completed, the FSP may be able to leverage the POS data to actually extract the store name, brand, and location, and from the UPC identify the product on the digital receipt the user may want to use. The additional visibility for brand names provided by the “one-touch-one-tap” payment process may be an add-on service to the merchant. In the process flow for the payment instrument, this visibility creates a difference from the conventional consumer experience that at a retail store, the POS displays only the networks' brands (e.g., Visa °, MasterCard®, and others). The FSP payment engine may allow an advantage as to bringing the bank (for example) brand presence on the mobile handset, providing user visibility and creation of services around this visibility for merchants and banks.
FIG. 11 is an entity-relationship diagram illustrating secure identity binding (SIB) system 1100, which may operate in conjunction with TIM 400. An example of SIB is described with reference to near field communication (NFC) for purposes of illustration. Thus, NFC in this context is used as an example of a communication layer only and embodiments of the invention neither rely nor depend on NFC technology, which is used merely as an instance of a generic communication channel. NFC is a point-to-point wireless communication technology (as distinguished, e.g., from a protocol) that is based on the ISO 14443 proximity-card standard. NFC uses short-range, high-frequency signals to enable two-way interaction between electronics devices. A device called a “tag” (also referred to as an RFID tag) is commonly used in conjunction with NFC technology. A tag is a small physical object that can be attached to, or incorporated into a product. An RFID tag contains within it a unique digital identifier (usually a numeric value.) Tags are physically attached to a device that accepts payment (for example, a laundromat washing machine or a vending machine). Tags also contain silicon chips that enable them to receive and respond to queries from a device called an RFID reader/writer. An NFC-enabled mobile phone also could be a tag reader.
An identity validation issue that arises in general is how to securely “bind” the tag to the device. That is, how to ensure that the tag does indeed identify the physical device to which it is attached. Current techniques are typically based on physical binding such as gluing the tag to the device. Not only may this be expensive and present maintenance problems, it is also not secure. For example, an attacker could cover the original tag with electromagnetic shielding material such as aluminum foil, and then attach the attacker's own spoofed tag on top of the original one (thus impersonating the device) or simply swap the tags on two devices. The outcome is the same: the identity-binding assumption is violated.
Some tags are digitally signed. In this case the reader could verify the integrity of the tag by way of verifying the digital signature embedded in the tag (e.g., verifying the identity-binding using public key infrastructure (PKI)). The assumption of this verification is that the reader trusts the signer of the tag data by way of trusting the copy of the digital certificate that contains the public key of the signer. Signed-tag identity-binding verification does not solve the identity-binding problem. In other words, signed-tag identity-binding verification addresses the integrity verification of the tag itself but not the secure binding between the tag and the device. This is considered a fundamental identity management problem and becomes even more important when financial transactions are involved in the interactions between the tag and the device.
As illustrated in FIG. 11, identity-binding verification in accordance with one or more embodiments implements a verifiable logical binding that does not rely on the unverifiable physical binding between the tag 1102 and the device 1104. In a one-time operation, the tag identifier (referred to as “Tag ID”) is stored in a hardware secure storage 1106 on the device using a trusted software component, e.g., trusted agent (TA) 1108. Then every time that the tag 1102 is read by a reader 1110, such as a mobile phone 510, the Tag ID is verified with the content of the hardware secure storage 1106, also referred to as secure vault 1106. If there's a match, then the Tag ID is trusted and is presumed to represent the identity of the device 1104.
One embodiment requires the following components on the device 1104: secure vault 1106 and TA (trusted agent) 1108. The secure vault 1106 is a secure storage mechanism that holds private identifying key material such as digital private keys. Secure vault 1106 could be hardware-based such as a Trusted Platform Module (TPM), Mobile Trusted Module (MTM), embedded secure element (eSE), or it could be a software security entity, such as a password-protected file such as a software key store. Hardware-based secure vaults are preferred as they potentially provide a much higher level of protection and are not susceptible to software-only attacks (also known as system-wide attacks). Software-based secure vaults are also possible, however, albeit possessing lower security characteristics.
The trusted agent or TA 1108 is a software entity that is trusted and the integrity of which is verified every time the TA 1108 is used. For example, TA 1108 may be a trusted remote attestation agent (TRAA) in accordance with an embodiment and as described below with reference to FIG. 13. The presence of a TA 1108 on the reader 1110 (such as a mobile phone 510) is preferred but not necessary. That is, if other security mechanisms exist on the reader 1110 that assert the trust, then the identity-binding verification will be as effective as if there were a TA 1108 present on the reader 1110. Reader 1110 may also have a secure vault 1116.
Trust establishment and verification may be achieved as follows:
1) TA 1108 is created by the device manufacturer (or a trusted third party, TTP) and is put on the device 1104.
2) A cryptographic, one-way, hash function of TA 1108 is calculated; call it H1(TA).
3) H1(TA) is digitally signed by a trusted entity called Trust Anchor 1112 (for example, the FSP 1114 or a device manufacturer may also act as Trust Anchor 1112). The digital signature is a PKI operation which means that the Trust Anchor 1112 owns a pair of public and private keys (namely Keypublic and Keyprivate respectively.) The H1(TA) data piece is digitally signed by Trust Anchor 1112 using its Keyprivate. The signed hash of TA 1108 is referred to as S(H1(TA), Keyprivate) The notation S(H1(TA), Keyprivate) does not indicate that Keyprivate either appears or is somehow accessible in this data entity; the notation is a conventional mathematical function notation indicating that Keyprivate is used for the calculation. The value of Keyprivate can not be inferred from this data.
4) To verify the integrity of S(H1(TA), Keyprivate) one only needs to have access to, and trust the integrity of Keypublic belonging to Trust Anchor 1112.
5) The digital signature verification process is a software operation, which may also be very fast. The software component that performs digital signature verification is referred to as the V. The software component “V” operates as: V(S(H1(TA), Keyprivate), Keypublic) and returns TRUE or FALSE (meaning signature verification successful or failed, respectively.)
6) To optimize the secure vault memory usage, a cryptographic one-way hash function of Keypublic is also calculated. Call it H2(Keypublic). H1 and H2 could be the same cryptographic one-way hash function or could be different cryptographic one-way hash functions.
7) Keypublic is loaded into the device's 1104 general memory (e.g., random access memory or RAM).
8) S(H1(TA), Keyprivate) as well as H2(Keypublic) and V are stored in a read-only area of the memory of device 1104, such as read-only memory (ROM), for example, by the device manufacturer. V should also reside or be placed in an executable area of ROM.
9) Now the integrity and authenticity of TA 1108 can be verified—and this verification can be trusted—every single time TA 1108 is used. Verification proceeds as:

    
    
        9.1) V is executed in ROM of device 1104 (if ROM contains executable area and V resides there). The trust on V is as strong as the protection of ROM (which is hardware-protection, meaning it is not susceptible to software-only attacks.)
        9.2) H2(Keypublic) is calculated and verified against H2(Keypublic) in the secure vault 1106. If verification fails, then the device 1104 is considered tampered-with. If verification succeeds, then Keypublic (which is present in RAM of device 1104) is considered trustworthy.
        9.3) V(S(H1(TA),Keyprivate),Keypublic) is calculated. If V succeeds (i.e. V returns TRUE) then TA 1108 can be trusted. Otherwise the system 1100 is considered tampered-with.
    
    


10) At this point, assuming V succeeds, TA 1108 can be trusted, and therefore whatever TA 1108 trusts can also be trusted. From this point on TA 1108 accesses and verifies the Tag ID stored in secure vault 1106, and responds to reader's 1110 requests for Tag ID, Since TA 1108 is trusted, the responses of TA 1108 to requests are trusted.
The secure identity binding in accordance with one or more embodiments involves a one-time-per-tag provisioning process. That is, once a tag 1102 is attached to the device 1104, the Tag ID is read and stored in the device's 1104 secure vault 1106 by the Trust Anchor 1112 and using TA 1108. On subsequent tag 1102 replacements (e.g. for maintenance purposes) the provisioning process may be repeated so that the Tag ID of the current tag 1102 always is present in the secure vault 1106. Further security augmentation could be implemented. For example, records of the device-tag ID, the GPS (Global Positioning System) location of the device, and other data could be stored within the FSP 1114 infrastructure (such as TIM 400). This infrastructure could be consulted for risk management operations and other security, authentication, and identification purposes.
After the provisioning phase, whenever a reader 1110 (such as an NFC-enabled mobile phone or other consumer electronic device that could be used for payment) reads the Tag ID attached to the device 1104, the reader 1110 communicates that Tag ID to the device's 1104 TA 1108. The communication between the reader 1110 and device's 1104 TA 1108 can be trusted because the communication happens between two trusted entities (e.g., the reader 1110 and device's 1104 TA 1108). Eavesdropping this communication channel is difficult (for example, using NFC, communication occurs within a short proximity) and even if done successfully, does not yield any useful attack vector for the attacker. The reason for this assertion is that the attacker has to be able to successfully: 1) send a spoof signal (i.e. spoofed Tag ID) to the reader 1110, and 2) block the response sent by device's 1104 TA1108.
The chances of satisfying the foregoing two conditions are miniscule in practice. Now if the Tag ID reported by the reader 1110 does not match the Tag ID in the secure vault 1106 of device 1104, then the TA 1108 responds with a “no-match” message back to the reader 1110, optionally logs the event, puts the device on “hold” state as this might indicate a tag-tampering or tag-replacing attempt. A “potential-tag-tampering” message could also be sent to the FSP 1114 infrastructure (by the device 1104, reader 1110, or both) to put the device 1104 on an “elevated-risk” status and help FSP 1114 with its distributed risk management infrastructure (including, e.g., TIM 400).
If the device 1104 does not include a secure vault or TA, then the Tag ID could be sent to the FSP 1114 infrastructure (e.g. TIM 400 database) during the provisioning process. In this case, whenever a reader 1110 attempts a transaction using such a Tag ID, then the GPS location of the reader 1110 (assuming the reader 1110 is GPS-capable) may be sent to FSP 1114 infrastructure, and then FSP 1114 sends a message back to the reader 1110 with usable identifying information (including, for example, a message such as “our records show this is a vending machine, located in 2211 North First St., San Jose, Calif.”, or a picture of the device 1104) that could assist the user of reader 1110 in determining whether the device 1104 is legitimate.
FIG. 12 is a system block diagram illustrating an example of a hardware-based zero knowledge strong authentication (H0KSA) system 1200. One of the fundamental pillars of security is strong authentication. The strongest form of authentication involves the combination of more than one authentication factor. One such combination of factors may be categorized as: 1) what you know, e.g., passwords, passphrases; 2) what you have, e.g., hardware tokens, private keys; and 3) what you are, e.g., biometrics. When combined properly, these artifacts force an intruder to compromise several factors before being able to mount a meaningful attack. Although most strong authentication systems are single-factor systems, they can be combined with an additional factor, like a software or hardware token, to construct a multifactor system. What distinguishes strong authentication systems from other, weaker one-factor methods is the level of security that they leverage from that one factor. A strong authentication system must protect even low-entropy (“guessable”) authentication methods from off-line attacks, even against adversaries with complete access to the communication channel. Strong authentication systems typically exchange a session key as well, which enables both data confidentiality and integrity after authentication has been successfully performed.
Many password authentication systems claim to solve this exact problem, and new password authentication systems are constantly being proposed. Although one can claim security by devising an authentication system that avoids sending the plaintext secrets (e.g., proofs) unencrypted, it is much more difficult to devise an authentication system that remains secure when: 1) attackers have complete knowledge of the protocol; 2) attackers have access to a large dictionary of commonly used passwords; 3) attackers can eavesdrop on all communications between client and server; 4) attackers can intercept, modify, and forge arbitrary messages between client and server; and 5) a mutually trusted third party is not available.
H0KSA system 1200 employs a strong authentication mechanism that is based on “Zero Knowledge proof” and is augmented by hardware-based protection of secret key material, as well as optional biometric technologies on the client systems to initiate the authentication process. H0KSA system 1200 solves the problem of secure authentication in cases where the “prover” (e.g., a requester of authentication) must own some secret material (such as private key material) and carries no other secret information, and where the “verifier” (e.g., the recipient of the authentication request, such as TIM 400) decides whether or not the authentication request should be granted. H0KSA system 1200 satisfies the following requirements: 1) system 1200 deploys hardware-security modules to store the secret material on the clients; examples of hardware-security modules include: TPM (Trusted Platform Module), MTM (Mobile Trusted Module), SE (secure element), eSE (embedded secure element), SD card (Secure Domain, a secure memory card such as TrustedFlash); 2) system 1200 may use biometric technologies (e.g., biometric device 1212) to initiate the authentication process; 3) system 1200 doesn't allow the attacker to impersonate the prover even if the communication channel between the prover and verifier is compromised; 4) system 1200 does not require a TTP (trusted third party) during the authentication process; and 5) system 1200 consumes less power for this operation than the typical PKI-based authentication, which makes system 1200 suitable also for battery-powered hand-held devices.
Many devices contain a form of hardware security module. The challenge is to properly deploy the hardware security module and leverage its capabilities so that the applications that require protection could use the hardware security module consistently and securely. A H0KSA system 1200 accomplishes these tasks by storing the private key material in a hardware protected security device and allowing access to it only through a secure and authenticated mechanism. This authentication mechanism is based on Zero Knowledge Proof.
FIG. 12 illustrates one embodiment of a H0KSA system 1200 and its components. Fundamental features of H0KSA system 1200 include 1) establishing unbroken, end-to-end (E2E) security 1202; and 2) enabling fast, power-efficient, and strong authentication. Each of these features is described below. System 1200, while very relevant for consumer electronic devices (CED), is also applicable for non-CED environments.
An essential element of security is establishing an un-broken trust chain during both of two phases referred to as the authentication phase and the channel protection phase. When the trust-chain is weakened, broken, or flawed, then hackers have an opportunity to exploit the weaknesses and attack the system. For example, assume that A and B need to authenticate each other prior to establishing a communication channel, as diagrammatically indicated by:
A←[communication channel]→B
A and B may be called end-points of the communication channel because in real world scenarios the communication channel passes through multiple connection points called hops, as diagrammatically indicated by:
A←[(hop_0)←→(hop_1)← . . . →(hop_n)]→B
End-points could be local (that is, the end-points reside within the same device or execution environment) or the end-points could be foreign (that is, the end-points belong to different devices or execution environments.) One example of local end-points is the common design for computing devices such as a personal computer (PC), a laptop, or other CEDs. An example of foreign end-points is that of two (usually) physically separate systems communicating remotely. In real life scenarios the usual case is typically a hybrid one, for example, a combination of local and foreign end-points involved in communication and data transfer.
An important characteristic of H0KSA system 1200 is the establishment of a verifiable E2E (end-to-end) trust 1202 that is rooted in a hardware security module (HSM) 1204 that is referred to as root of trust (ROT) 1206. The chain from ROT 1204, 1206 to the component using ROT 1206 is called chain of trust (COT) 1202. It is critically important that COT 1202 satisfies the following two conditions at each step of the way, from hardware ROT 1204, 1206 up to the component that leverages ROT 1206: 1) channel protection; and 2) mutual authentication. A communication channel satisfying these two conditions for each link (e.g. hop or step) in the channel is referred to as an unbroken chain of trust. If the unbroken chain of trust extends from the first end point (e.g., the root of trust) to the second endpoint (e.g., point requiring authentication), it is referred to as an end-to-end chain of trust.
Channel protection means that the communication channel between the two end-points must be protected at each step of the way, as in the second diagram above. Channel protection also implies that the channel contents can not be easily eavesdropped. That is, eavesdropping efforts would be either very expensive, very time-consuming, or would require a nontrivial level of technical knowledge commonly unavailable. This type of channel protection is typically accomplished by using hardware protection, strong encryption, or both.
Mutual authentication means that at each step of the way, as in the second diagram above, the end-points of each communication-hop authenticate each other. The mutual authentication condition can be relaxed if other protection mechanisms are in place, or if the risks associated with relaxing this condition are miniscule, as far as system E2E security (e.g. COT 1202) is concerned.
At this point and by meeting the conditions of channel protection and mutual authentication, the requirements for a first fundamental feature of H0KSA system 1200—that of establishing unbroken, E2E security—are met. The following describes how the requirements for a second fundamental feature of H0KSA system 1200—that of enabling fast, power-efficient, and strong authentication—are met.
HSM 1204 includes a hardware-protected area of memory which is referred to as a secure vault 1208. Hardware-protection in this context means that the contents of memory could only be accessed by privileged and authenticated entities, hence the term secure vault 1208. To illustrate by example, assume that some private key material Key(private) (e.g., some digital data that is not to be accessible to the general public) is stored in the secure vault 1208. Key(private) may possess the following qualities: 1) Key(private) is unique, cannot be forged or guessed; it is hence the device's identity; 2) Key(private) is inaccessible by unauthenticated and unintended entities, because Key(private) is stored in secure vault 1208; and 3) Key(private) can therefore be used to strongly authenticate the device 1210. These three qualities satisfy the strong authentication requirement of the second fundamental feature of H0KSA system 1200.
Satisfaction of the fast and power-efficient conditions for the second fundamental feature of H0KSA system 1200 is described as follows: Key(private) may be used as the proof-material for Zero Knowledge Proof of Knowledge. That is, the device 1210 stores the Key(private) in the secure vault 1208 area of its HSM 1204, and then uses it to engage in a Zero Knowledge Proof with outside entities that need to authenticate it. This mechanism guarantees that Key(private) remains private. Zero Knowledge Proof implementations are much faster mechanisms compared to other mechanisms (about two orders of magnitude, for example, compared to RSA-based identification schemes), and therefore require less computation (e.g., number of processing cycles). This satisfies the fast condition required for the second fundamental feature of H0KSA system 1200. There is a direct correlation between the number of processing cycles and the power consumption of the device performing the computation, hence satisfying the power-efficient condition required for the second fundamental feature of H0KSA system 1200.
FIG. 12A illustrates a method 1280 for providing a hardware-based zero-knowledge strong authentication according to the fundamental features of H0KSA system 1200. At step 1282, the method 1280 may protect some secret information of any form that may be the subject of a zero-knowledge proof. In one embodiment, the secret information may be a private key having characteristics described above—such as resistance to forgery or to being guessed, inaccessibility to unauthenticated and unintended entities—that make the private key suitable for uniquely identifying a device, for strongly authenticating the device, and for being the subject of a zero-knowledge proof of knowledge. Protection may be accomplished, for example, using an HSM (e.g., HSM 1204), secure vault (e.g., secure vault 1208), and use, for example, of a trusted agent (e.g., trusted agent 1108) for storing the secret material in the secure vault.
At step 1284, method 1280 may establish an end-to-end chain of trust over a communication channel from one endpoint containing the secret material to another endpoint requiring to authenticate the secret material, satisfying the conditions described above, e.g., hardware or encryption (or both) protection of the channel and mutual authentication of the endpoints. Each communication hop, or link, of the channel may also satisfy the same conditions, e.g., protection and endpoint mutual authentication, in order for an unbroken chain of trust to be considered established for the communication channel.
At step 1286, method 1280 may authenticate the secret material using zero-knowledge proof over the end-to-end chain of trust established for the communication channel. At step 1288, the zero-knowledge proof may comprise a zero-knowledge proof of knowledge; the secret material may be a private key, suitable for identifying a device and suitable for use as proof material for zero-knowledge proof of knowledge; and the device itself may be authenticated while the secret material, i.e., the private key, remains private to the device.
Zero Knowledge Proof is a formal mathematical concept. One fundamental quality of this class of formal proof systems is called indistinguishability. Any mathematical proof system (such as Zero Knowledge) has two classes of actors: prover (who proves the claim) and verifier (who verifies the proof offered by the prover.) To evaluate and assess the security and safety of the proof offered in such systems, the verifier is considered either an honest verifier (that is, the verifier follows the proof system protocol verbatim) or a dishonest verifier (that is, the verifier does not follow the protocol verbatim.) This technique allows the system to verify the correctness of the claim irrespective of whether the protocol suggested by the prover is followed by the verifier. An important side effect of this quality is indistinguishability. That is, in order for the proof to be asserted (meaning, no “knowledge” of the secret is released) it should be indistinguishable from verifier's point of view irrespective of verifier's honesty. In simpler terms, no knowledge is leaked about the secret, or the way that the possession of the secret is proved.
FIG. 13 is an entity-relationship diagram illustrating an MEP (mobile embedded payment) system 1300 and a trusted remote attestation agent (TRAA) 1302 and system level operational relationships. Determining the security status of a mobile device (e.g., mobile terminal 1304) that holds financial instruments is nontrivial. When such a device (e.g., mobile terminal 1304) is offline (that is the communication with home network 1306 (e.g., MNO cloud 1306), which is the network to which the device is subscribed to, becomes unavailable) performing this task becomes even more difficult because typical remote pulse-check techniques are not applicable. For mobile phones (e.g., mobile terminal 1304), one vector of attack for hackers to obtain privileged-access to the terminal is to remove or otherwise disable the SIM (Subscriber Identity Module) card 1308 and interrupt the communication channel between the phone 1304 and the mobile network 1306 and other endpoints such as those of financial service providers (FSP) 1310. This type of attack will ease the hackers' attempt to circumvent network-based security mechanisms that are put in place to protect the integrity and confidentiality of financial instruments on the device. This will increase the chance of mounting a successful attack and in turn results in an increased risk to financial institutions (e.g., bank 1314, FSP 1310), thus hindering the efforts to enable offline transaction capabilities on the mobile phone 1304.
TRAA 1302 addresses these problems by providing a set of pulse-check steps to ensure that the security-sensitive connections (e.g., connections 1305, 1309) are available and active. If a vital check fails then a predetermined restriction may be enforced. The security provided by TRAA 1302 may be considered to be as good as the strength of the enforcement mechanism of restriction rules.
The security provided requires the presence of TRAA 1302 on the mobile device 1304. TRAA 1302 may be, for example, a software application that satisfies the following requirements:
1) TRAA 1302 is trustworthy itself. That is, TRAA 1302 is either stored in a hardware secure module such as eSE (embedded Secure Element) 1312 or TPM (Trusted Platform Module), or its integrity can be verified and attested to. Mechanisms to establish this integrity check include (but not limited to) digital signature verification or oblivious hashing (OH) techniques.
2) TRAA 1302 has knowledge of the same SIM card 1308 that was present when the mobile phone was provisioned with the financial instrument by way of storing and protecting the SIM card's unique identifier value. (See, e.g., FIG. 9, arrows 902, 904 and arrows 922 through 924) This SIM card is referred to as the provisioning-SIM 1308.
3) TRAA 1302 implements a method to periodically:

    
    
        3.1) Verify self-integrity: if this verification fails, the financial instruments on the phone 1304 are put in “lock-state”. That is, the financial instruments need to be re-enabled by calling the service center (mobile operator 1306, or financial institution (e.g., bank 1314 or FSP 1310), or both.)
        3.2) Check the existence of the provisioning-SIM: if this check fails, then the financial instruments are put on “hold-state”. That is, once the provisioning-SIM 1308 is available again the financial instruments will become available to use.
        3.3) Check the connectivity to MEP (Mobile Embedded Payment) Backend services (e.g., TIM 400, FSP 1310). TIM 400 may be part of FSP's 1310 infrastructure to support payment on consumer electronics devices such as mobile phones 1304.
        3.4) Check the connectivity 1305 to home mobile network 1306: if this check fails, then the financial instruments are put on “cap-state”. That is, a predetermined transaction cap (e.g. $20) is enforced and transactions with a value above this amount are denied until and unless all the vital checks (e.g., existence of the provisioning-SIM 1308, connection 1309 to MEP Backend (e.g., TIM 400), and connection 1305 to home mobile network 1306) become available.
        3.5) The frequency of the above pulse-check mechanisms may be tuned by the MEP system 1300 (e.g., TIM 400, FSP 1310). Furthermore this may be a function of the risk-profile associated with the user, mobile phone 1304, and the location (e.g., using geo-location techniques with GPS) from where the transactions are initiated.
    
    


TRAA is not limited strictly to mobile devices such as mobile phone 1304, and may also be useful for other consumer electronic devices—including, for example, NetTVs and NetTops—for which the SIM 1308 may be substituted by another uniquely identifiable available network communication element.
FIG. 14 is an example of an interactive phishing detection (IPD) visual indicator 1402 in accordance with an embodiment. An important aspect of any open model such as that of the Internet is, by definition, that the applications can be written by anybody; not just the original source. That is, the mere fact that a viable business has legitimate services to offer on its website does not stop malicious entities from posing as the genuine website and harvesting users' credentials. This artifact of open models poses an important security challenge, which is how to identify and stop a rogue application. An important class of rogue software is phishing applications. Phishing is defined as the process of attempting to acquire sensitive information such as user credentials (e.g., username, password, or credit card details) by masquerading as a trustworthy entity. Phishing is a nontrivial problem, solutions to which may require multiple entities in various layers of the ecosystem to cooperate and participate. As the problem is distributed, it makes sense that solutions should likewise be so distributed.
Phishing-prevention is a highly complex problem; one that possesses both technical and social-engineering facets. Determining whether an application is rogue, or otherwise unauthorized to perform an action is a nontrivial task that depends on many factors such as the Operating System (OS) and the software platform (also referred to as stack) on which the application runs, its user interface (UI) composition, its interaction model with other applications and services, and many other factors. The definition of rogue itself is also very generic and imprecise. At an abstract level, solving the phishing problem is equivalent to identifying and allowing an authentic application (and consequently allowing it to acquire the aforesaid credentials) and at the same time identifying and disallowing a rogue application, which impersonates as an authentic application. Therefore it is important to define the objective of the solution.
The main objective of the solution may be defined as interactive phishing detection (IPD). Any of MEP systems 500, 600, 700, and 800 may include an IPD module 4704 as part of TIM 400, as shown in FIG. 4B. The solution (e.g., implementation via IPD module 4704) does not attempt to prevent phishing, as that would require enumerating all the phishing attacks possible, which is practically impossible. Thus we further confine the scope of the solution as: A) enabling users to securely determine whether an application is authentic; and B) functionality of IPD is initiated by the end user who intends to verify the authenticity of the application. The restrictions A and B imply that the solution relies on the user's intention and invocation of IPD (e.g., via IPD module 4704 included in device management module 470) is not necessarily automatic. One example of a practical use of IPD is to assert the authenticity of an FSP payment engine, embedded in another application that requires payment functionality.
An embodiment of IPD may include two components: a client component (e.g., mobile phone 510) and a server component (e.g. TIM 400 including IPE module 4704). The client component resides on the target device (e.g., mobile phone 510, personal computer, laptop, mobile handset) that satisfies the following general requirements: 1) is network-aware; 2) is itself trustworthy; 3) contains a UI (user interface) element; 4) has a verification engine; 5) can be embedded or standalone; 6) its trustworthiness can be verified (i.e. can be authenticated).
The client component (e.g., mobile phone 510) is called a Trust Base, as it is able to establish and verify a trust claim (i.e. it is not tampered with). At a high-level and with the characteristics mentioned above, the Trust Base ensures that when an application is being executed and while it is obtaining users' credentials (and if the user chooses to) the authenticity of all the elements involved in the process can be verified. If this verification fails, then the user is notified via a visual indicator provided by the UI element, which in turn indicates a possible phishing attempt.
The server component (e.g. TIM 400 including IPD module 4704) is called a Trust Source as it generates verification material in a random manner that can be obtained by the client component, and also can be visually verified by the user. For example, the verification material can be a red, or other color or shading, button with a three-digit number in it forming an IPD visual indicator 1402, as seen in FIG. 14.
For the IPD visual indicator 1402 example, the button color and the numbers within it change randomly and periodically. This IPD visual indicator 1402 button is shown, for example, at a standard location on the Trust Source website (e.g., a website of the FSP 1310).
One implementation of IPD works as follows. When the user decides to verify whether the questionable software is authentic:
1) User clicks on the verify button (available, e.g., on the UI component of the client 510);
2) Verify button forces the verification engine to authenticate the client 510 to the server 400;
3) Upon a successful authentication of the client 510 by the server 400:

    
    
        a) The client 510 verification engine retrieves the current color settings (for the button and the number) as well as the digit value of the IPD visual indicator 1402 from server 400;
        b) The UI component of the client 510 shows the button with the color setting and number of the IPD visual indicator 1402 retrieved by the client 510 verification engine.
    
    


4) User visits the Trust Source site (e.g. website of the FSP 1310) and verifies that the color and number of the IPD visual indicator 1402 shown by the verify button of the user's client 510 component is the same as the one displayed on the Trust Source site.
The server (e.g., TIM 400) component only responds to an authentic client (e.g., mobile phone 510) component, as there is an authentication step required by the server (e.g., TIM 400) to send any response. A rogue application would not be able to authenticate, and can only guess the correct combination of colors and numbers. Since this combination is randomly set on the server (e.g., TIM 400 of Trust Source website of the FSP 1310), and is also changing periodically, the window of opportunity for the rogue application is severely limited.
In implementation of the various embodiments, embodiments of the invention may comprise a personal computing device, such as a personal computer, laptop, PDA, cellular phone or other personal computing or communication devices. The payment provider system may comprise a network computing device, such as a server or a plurality of servers, computers, or processors, combined to define a computer system or network to provide the payment services provided by a payment provider system.
In this regard, a computer system may include a bus or other communication mechanism for communicating information, which interconnects subsystems and components, such as processing component (e.g., processor, micro-controller, digital signal processor (DSP), etc.), system memory component (e.g., RAM), static storage component (e.g., ROM), disk drive component (e.g., magnetic or optical), network interface component (e.g., modem or Ethernet card), display component (e.g., CRT or LCD), input component (e.g., keyboard or keypad), and/or cursor control component (e.g., mouse or trackball). In one embodiment, disk drive component may comprise a database having one or more disk drive components.
The computer system may perform specific operations by processor and executing one or more sequences of one or more instructions contained in a system memory component. Such instructions may be read into the system memory component from another computer readable medium, such as static storage component or disk drive component. In other embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the invention.
Logic may be encoded in a computer readable medium, which may refer to any medium that participates in providing instructions to the processor for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. In various implementations, non-volatile media includes optical or magnetic disks, such as disk drive component, volatile media includes dynamic memory, such as system memory component, and transmission media includes coaxial cables, copper wire, and fiber optics, including wires that comprise bus. In one example, transmission media may take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications.
Some common forms of computer readable media include, for example, floppy disk, flexible disk, hard disk, magnetic tape, any other magnetic medium, CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, ROM, EPROM, FLASH-EPROM, any other memory chip or cartridge, carrier wave, or any other medium from which a computer is adapted.
In various embodiments, execution of instruction sequences for practicing the invention may be performed by a computer system. In various other embodiments, a plurality of computer systems coupled by communication link (e.g., LAN, WLAN, PTSN, or various other wired or wireless networks) may perform instruction sequences to practice the invention in coordination with one another.
Computer system may transmit and receive messages, data, information and instructions, including one or more programs (i.e., application code) through communication link and communication interface. Received program code may be executed by processor as received and/or stored in disk drive component or some other non-volatile storage component for execution.
Where applicable, various embodiments provided by the present disclosure may be implemented using hardware, software, or combinations of hardware and software. Also, where applicable, the various hardware components and/or software components set forth herein may be combined into composite components comprising software, hardware, and/or both without departing from the spirit of the present disclosure. Where applicable, the various hardware components and/or software components set forth herein may be separated into sub-components comprising software, hardware, or both without departing from the scope of the present disclosure. In addition, where applicable, it is contemplated that software components may be implemented as hardware components and vice-versa.
Software, in accordance with the present disclosure, such as program code and/or data, may be stored on one or more computer readable mediums. It is also contemplated that software identified herein may be implemented using one or more general purpose or specific purpose computers and/or computer systems, networked and/or otherwise. Where applicable, the ordering of various steps described herein may be changed, combined into composite steps, and/or separated into sub-steps to provide features described herein.
The foregoing disclosure is not intended to limit the present invention to the precise forms or particular fields of use disclosed. It is contemplated that various alternate embodiments and/or modifications to the present invention, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described various example embodiments of the disclosure, persons of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the invention. Thus, the invention is limited only by the claims.

## Claims

1. A user device configured to communicate with a verifying device that is distinct from the user device, the user device comprising:
a hardware security module (HSM) controlling access to a secret material stored within the HSM that-provides a basis for a zero-knowledge proof authentication of the user device over a communication channel that provides a chain of trust between the user device and the verifying device, with a mutual authentication between endpoints of each hop of the chain of trust; and
a tag configured to be readable by the verifying device to convey a tag identifier;
wherein the user device is configured to:
respond to the verifying device in the zero-knowledge proof authentication of the user device;
receive, after the user device completes the zero-knowledge proof authentication, the conveyed tag identifier from the verifying device via the communication channel; and
in response to determining that the received conveyed tag identifier matches a stored tag identifier stored within the HSM, communicate to the verifying device using the chain of trust that the received conveyed tag identifier is trusted as representing the identity of the user device.

2. The user device of claim 1, wherein:
the secret material is a private key material;
the private key material is unique and resistant to forgery and to being guessed such that the private key material serves as an identity of the user device; and
the private key material is a proof material for the zero-knowledge proof to authenticate the user device.

3. The user device of claim 1, wherein:
the secret material is a private key material;
the private key material is unique such that the private key material serves as an identity of the user device;
the private key material is a proof material for the zero-knowledge proof to authenticate the user device; and
the private key material remains private after the zero-knowledge proof authentication of the device is completed such that the private key material is not disclosed to the verifying device.

4. The user device of claim 1, wherein:
the HSM includes a secure vault;
the secret material is stored in the secure vault; and
the secure vault provides hardware-based protection of the secret material.

5. The user device of claim 1, wherein the HSM comprises at least one of a Trusted Platform Module (TPM), a Mobile Trusted Module (MTM), a secure element (SE), an embedded secure element (eSE), a secure memory card, a Secure Domain (SD) card, or a Trusted Flash memory.

6. The user device of claim 1, wherein the communication channel is protected by encryption.

7. The user device of claim 1, wherein the communication channel is hardware protected.

8. The user device of claim 1, wherein:
the communication channel includes one or more communication hops, each hop having two endpoints, wherein
each hop of the communication channel is protected; and
the endpoints of each hop mutually authenticate each other such that the communication channel provides an end-to-end chain of trust from the user device to the verifying device.

9. The user device of claim 1, further comprising a biometric device in response to an activation of which by a user, the user device is configured to initiate a request for the zero-knowledge proof authentication.

10. A method comprising:
establishing a chain of trust over a communication channel between a user device having a tag, configured to be readable by a verifying device to convey a tag identifier, and the verifying device, with a mutual authentication between endpoints of each hop of the chain of trust;
controlling access to a secret material in a hardware security module of the user device to provide a zero-knowledge proof authentication of the user device via the chain of trust;
engaging with the verifying device in the zero-knowledge proof authentication of the user device;
receiving, by the user device after the user device completes the zero-knowledge proof authentication, the conveyed tag identifier from the verifying device via the chain of trust; and
in response to determining that the received tag identifier matches a stored tag identifier stored within the hardware security module, communicating by the user device to the verifying device via the chain of trust that the conveyed tag identifier is trusted as representing the identity of the user device.

11. The method of claim 10, wherein the secret material serves to uniquely identify the user device.

12. The method of claim 10, further comprising:
authenticating the user device using the secret material as proof material in a zero-knowledge proof wherein the secret material remains private after authentication of the user device.

13. The method of claim 10, further comprising:
protecting the secret material by providing hardware protection including storing the secret material in a secure vault comprising a read-only memory (ROM).

14. The method of claim 10, further comprising:
protecting the secret material by using a trusted agent to store the secret material in a secure vault.

15. The method of claim 10, further comprising:
protecting the secret material by storing the secret material in at least one of a Trusted Platform Module (TPM), a Mobile Trusted Module (MTM), a secure element (SE), an embedded secure element (eSE), a secure memory card, a Secure Domain (SD) card, or a Trusted Flash memory.

16. The method of claim 10, wherein establishing the chain of trust comprises protecting the communication channel by encryption.

17. The method of claim 10, wherein establishing the chain of trust comprises providing hardware protection for the communication channel.

18. The method of claim 10, wherein:
the communication channel includes one or more communication hops, each hop having two endpoints; and establishing the chain of trust further comprises:
protecting each hop of the communication channel; and
mutually authenticating each other by the endpoints of each hop to establish an end-to-end chain of trust.

19. The method of claim 10, further comprising:
establishing an end-to-end chain of trust over the communication channel, wherein:
the communication channel has two endpoints, the hardware security module being at a first endpoint and the verifying device being at a second endpoint; and
an unbroken chain of trust is established between the first endpoint and the second endpoint of the communication channel.

20. A non-transitory machine-readable medium having stored thereon machine-readable instructions executable to cause a machine to perform operations comprising:
establishing a chain of trust over a communication channel between a user device having a tag, configured to be readable by a verifying device to convey a tag identifier, and the verifying device, with a mutual authentication between endpoints of each hop of the chain of trust;
controlling access to a secret material in a hardware security module of the user device to provide a zero-knowledge proof authentication of the user device via the chain of trust;
responding to the verifying device in the zero-knowledge proof authentication of the user device;
receiving, by the user device after the user device completes the zero-knowledge proof authentication, the conveyed tag identifier from the verifying device via the chain of trust; and
in response to determining that the received tag identifier matches a stored tag identifier stored within the hardware security module, communicating by the user device to the verifying device that the conveyed tag identifier is trusted as representing the identity of the user device.