Parallel secret salt generation and authentication for encrypted communications

Abstract

In a method of facilitating encrypted communication between a transmission system and a receiving system having a unique identifier, a key generation system generates at least one encrypted master key for use with the unique identifier and an encryption algorithm to produce a transmission system unique encryption key. The key generation system also generates a shared secret master key for use with the unique identifier and a second encryption algorithm to produce a shared secret value. The at least one encrypted master key and the shared secret master key are then stored in an encrypted information database. The key generation system transmits the at least one encrypted master key and the shared secret information to the transmission system, and transmits the at least one encrypted master key, the shared secret master key, and the unique identifier to the receiving data processing system.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Patent Application No. 17 / 890,628, filed on August 18, 2022, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to cryptography, and more particularly, to systems and methods for cryptographic authentication of communication between data processing systems. Background Art

[0004] Data security and transaction integrity are crucial for enterprises and consumers. As electronic transactions account for an increasing proportion of business activities, this demand is also growing. Although data encryption algorithms have improved communication security, vulnerabilities still exist. For example, symmetric encryption technologies require that the sending and receiving systems must share information and software with each other. The process of transmitting this shared information itself may be vulnerable to attacks.

[0005] Therefore, there is a need to enhance the integrity of the information shared between communication partners, which is used for the encryption of transactions and other critical communications. Summary of the Invention

[0006] An illustrative aspect of the present invention provides a card that includes a data processor, a communication interface, and a card memory. The communication interface is configured to communicate with an intermediate processing device in a contact or non - contact manner. The card memory stores a shared secret master key, a unique card identifier, and a message encryption application therein. The message encryption application includes instructions for the data processor to generate a shared secret value using the unique card identifier and the shared secret master key. The application also includes instructions for generating a message authentication code using the shared secret value, encrypting at least a portion of the message content using a first session key to produce an encrypted message content, and encrypting the instructions for the message authentication code. The application further includes instructions for transmitting a message including the encrypted message content and the encrypted message authentication code to the intermediate processing device for re - transmission to a receiving communication processing system.

[0007] Another aspect of the present invention provides a method that facilitates symmetric encryption communication between a transmitting data processing system and a receiving data processing system, where the transmitting data processing system has a unique identifier associated therewith. The method includes: generating, by a key generation data processing system, at least one encrypted master key. Each encrypted master key is configured to be used with the unique identifier and a first encryption algorithm to generate a transmission system unique encryption key. The method further includes: generating, by the key generation data processing system, a shared secret master key. The shared secret master key is configured to be used with the unique identifier and a second encryption algorithm to generate a shared secret value. The method further includes: storing, by the key generation data processing system, at least one encrypted master key and the shared secret master key associated with the unique identifier in an encrypted information database. The method further includes: transmitting, by the key generation data processing system, at least one encrypted master key and shared secret information to the transmitting data processing system, and transmitting, by the key generation data processing system, at least one encrypted master key, the shared secret master key, and the unique identifier to the receiving data processing system.

[0008] Another aspect of the present invention provides a method for authenticating a message transmitted by a sending data processing system, where the sending data processing system has a unique identifier associated therewith, and where the transmitted message includes encrypted content and an encrypted message authentication code. The method includes actions performed by the receiving data processing system, including receiving the transmitted message, determining the unique identifier, and obtaining an encrypted information record of the sending data processing system. The encrypted information record includes the shared secret master key. The method includes further actions of the receiving data processing system, which include decrypting the encrypted message authentication code, generating a shared secret value using the unique identifier and the shared secret master key, and generating a comparison message authentication code using the shared secret value. The method further includes: comparing, by the receiving data processing system, the comparison message authentication code with the decrypted message authentication code to determine the message authentication result. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention can be more fully understood by reading the following detailed description in conjunction with the accompanying drawings, in which like reference numerals are used to represent like elements, and in which:

[0010] Figure 1 is a schematic diagram of a data transmission system that can be used to implement an embodiment of the present invention;

[0011] Figure 2 is a schematic diagram of a data transmission system that can be used to implement an embodiment of the present invention;

[0012] Figure 3 is a schematic diagram of a transaction card communication system according to an embodiment of the present invention;

[0013] Figure 4 is a schematic diagram of a transaction card data processing system that can be used to implement the embodiments of the present invention;

[0014] Figure 5 is a schematic diagram of a user device that can be used to implement the embodiments of the present invention;

[0015] Figure 6 is a schematic diagram of a transaction processor that can be used to implement the embodiments of the present invention;

[0016] Figure 7 is a schematic diagram of an issuing institution processing system according to the embodiments of the present invention;

[0017] Figure 8 is a schematic diagram of a card message processing system according to the embodiments of the present invention;

[0018] Figure 9 is a sequence diagram showing an action sequence for facilitating authenticated encrypted communication according to the embodiments of the present invention;

[0019] Figure 10 is a flowchart of actions in a method for facilitating authentication of an encrypted message according to the embodiments of the present invention;

[0020] Figure 11 is a flowchart of actions in a method for constructing an authenticated encrypted message according to the embodiments of the present invention; and

[0021] Figure 12 is a flowchart of actions in a method for authenticating an encrypted message according to the embodiments of the present invention. Detailed Embodiments

[0022] Although the present invention will be described in connection with specific embodiments and manufacturing environments, it should be understood that the present invention is not limited to these embodiments and environments. On the contrary, it is contemplated that various alternatives, modifications, and equivalents are included within the spirit and scope of the described present invention.

[0023] When using symmetric cryptographic algorithms such as encryption algorithms, hash-based message authentication code (HMAC) algorithms, and cipher-based message authentication code (CMAC) algorithms, it is important that one or more keys used remain secret between the party initially processing the protected data and the party receiving and further processing the data. It is also important that these values are not used too many times. Each time a key or salt is used, it provides the attacker with additional data samples processed by the encryption algorithm. The more data processed with the same key or salt the attacker obtains, the greater the likelihood that the attacker will discover these secret values.

[0024] Additional protection can be provided by using a message authentication code generated at least in part based on a secret value (sometimes referred to herein as a salt or secret salt) that may be included in an encrypted message. Like the information required to generate a session key for symmetric encryption, the secret value used to create the MAC must be shared by the sender and the receiver. Generally, this means the permanent or long-term storage and association of the shared value in each of the two systems. It also means that, at some point, the shared value must be transmitted from one of the communicating participants to the other, or from a third-party management entity to both participants. This transmission provides a potential vulnerability even before any encrypted message is passed between the sender and the receiver.

[0025] Example embodiments of the present invention provide systems and methods for symmetric cryptographic communication that incorporate message authentication using a shared secret value that can be dynamically generated by either or both of the sending and receiving systems. This not only provides the security of not maintaining the secret value in memory, but also provides the benefit that the information used to generate the secret value can be securely transmitted to either or both of the systems without transmitting the shared value itself. This has particular value when one of the two systems includes or is closely associated with a system configured to generate and control the secret value. A specific example of such a scenario is when one of the two communication processing systems is incorporated into a transaction card programmed and issued by a card issuer, and the second communication processing system is part of a transaction processing system.

[0026] Referring to Figure 1 , data transmission system 100 according to an example embodiment may include a transmitting or sending data processing system 110, a receiving or receiving data processing system 120, which communicate with each other via network 130 and with one or more servers 150. Processing systems 110, 120 may be or include any network-enabled processor computer system or device, including but not limited to any server, network device, personal computer (PC), workstation, mobile processing device such as a smartphone, smart board, handheld PC, or personal digital assistant (PDA), or a card-mounted microprocessor capable of directly or indirectly communicating over a network.

[0027] Network 130 may be or include a wireless network, a wired network, or any combination of a wireless network and a wired network, and may be configured to connect one or more transmission systems 110 and one or more receiving systems 120 to server 150. Network 130 may include, for example, a fiber optic network, a passive optical network, a cable network, an Internet network, a satellite network, a wireless LAN, a Global System for Mobile Communications (GSM), a Personal Communications Service (PCS), a personal area network, a Wireless Application Protocol (WAP), a Multimedia Messaging Service (MMS), an Enhanced Messaging Service (EMS), a Short Message Service (SMS), a time-division multiplexing (TDM)-based system, a code-division multiple access (CDMA)-based system, D-AMPS, Wi-Fi, fixed wireless data, IEEE 802.11b, 802.15.1, 802.11n, and 802.11g, Bluetooth, Near Field Communication (NFC), Radio Frequency Identification (RFID), Wi-Fi, etc.

[0028] In addition, network 130 may include, but is not limited to, a telephone line, fiber optic, IEEE Ethernet 902.3, a wide area network (WAN), a wireless personal area network, a local area network (LAN), or a global network such as the Internet. Further, network 130 may support an Internet network, a wireless communication network, a cellular network, etc., or any combination thereof. Network 130 may also include one network, or any number of the above-exemplified types of networks, operating independently or in cooperation with each other. Network 130 may utilize one or more protocols of one or more network elements to which it is communicatively coupled. Network 130 may convert other protocols into one or more protocols of network devices, or from other protocols into one or more protocols of network devices. Although network 130 is depicted as a single network, it should be understood that, according to one or more examples, network 130 may include multiple interconnected networks, such as, for example, the Internet, a service provider's network, a cable television network, a corporate network such as a credit card association network, and a home network.

[0029] A networked computer system for performing the methods contemplated by the present invention may execute one or more software applications, e.g., receive data as input from an entity accessing the networked computer system, process the received data, transmit data over the network, and receive data over the network. One or more networked computer systems may also include one or more software applications that send notifications to account holders or other users. It should be understood that Figure 1 the description in Figure 1 is merely exemplary, and the functions and processes described herein may be performed by any number of networked computers. It should also be understood that, in cases where the illustrated system 100 may have only a single instance of certain components, multiple instances of these components may be used. System 100 may also include other devices not shown in

[0030] In some examples, one or more transmission systems 110 and one or more receiving systems 120 may be configured to communicate with each other and / or with the server 150 without going through the network 130. For example, communication between the transmission system 110 and the receiving system 120 and / or the server 150 may occur via at least one of near field communication, Bluetooth, radio frequency identification, Wi-Fi, and / or the like. In some examples, either or both of the transmission system 110 and the receiving system 120 may include multiple devices capable of communicating with each other via the network 130, via another network, or via near field communication Bluetooth, radio frequency identification, Wi-Fi, etc.

[0031] In a typical usage scenario of the system 100, the sender and the receiver may wish to exchange data (e.g., raw sensitive data) via their respective systems 110 and 120. Although the following examples specifically relate to two systems 110, 120, it should be understood that additional transmission systems and receiving systems may be involved, and in some cases, the roles of transmission and reception may be reversed. However, the main requirement for participation is that each party shares a secret master key that can be used to generate a symmetric encryption key. In some examples, the transmission system 110 and the receiving system 120 may be configured with the secret master key. It should be understood that any other party or device capable of generating a symmetric encryption key or being provided with a symmetric encryption key may perform the functions of the transmission system 110 or the receiving system 120. However, in a typical example, the symmetric encryption key is a session key that is confidential to all parties other than the transmission system 110 and the receiving system 120 participating in the exchange of secure data.

[0032] In the method of the present invention, it may also be required that the transmission system 110 and the receiving system 120 maintain or generate a shared secret value that can be used to generate a message authentication code. As will be discussed in more detail below, in some embodiments, the shared secret value may be dynamically generated by one or both systems using the shared secret master key.

[0033] To prepare for encrypted transmission, the transmission system 110 can be configured to use an appropriate symmetric cryptographic algorithm to establish a secret session key using a secret master key. The symmetric algorithm used can include any symmetric cryptographic algorithm capable of generating a diverse symmetric key of a desired length. Non-limiting examples of symmetric algorithms can include symmetric encryption algorithms such as 3DES or AES128, symmetric HMAC algorithms such as HMAC-SHA-256; and symmetric CMAC algorithms such as AES-CMAC. It should be understood that if the output of the selected symmetric algorithm does not generate a key of sufficient length, techniques such as multiple iterations of processing the symmetric algorithm with different input data and the same master key may generate multiple outputs, which can be combined as needed to generate a key of sufficient length.

[0034] In some embodiments, additional parameters available to both the transmission system 110 and the receiving system 120 can be used in the construction of the shared symmetric session key. One example is a counter that is updated each time a communication from the transmission system 110 to the receiving system 120 is encrypted and transmitted. In some embodiments, the counter or other parameters can be included in the encrypted transmission and / or included in an unencrypted attachment accompanying the encrypted transmission.

[0035] The transmission system 110 can be configured to use the constructed symmetric encryption session key to process some or all of a set of information for transmission to the receiving system 120. For example, the transmission system 110 can encrypt the sensitive part of the data using a symmetric encryption algorithm and the session key, with the output including the encrypted information set. The transmission system 110 can then send a message including the encrypted information set. The message can also include unencrypted information, which can include, for example, information identifying the transmission system and / or information related to the nature of the encrypted information set. In a particular embodiment, additional communication parameters (e.g., a counter) can be included.

[0036] In certain embodiments, the sensitive data portion encrypted using the session key may include a message authentication code generated using a shared secret value. In some embodiments, the transmission system 110 may be configured with an assigned shared secret value, which may be stored in a memory included in or accessible to the transmission system 110. The transmission system 110 may be configured to obtain the stored shared secret value from the memory when constructing a message for transmission to the receiving system 120. The shared secret value may then be used as a salt value in any known encryption algorithm to generate a message authentication code. In some embodiments, the transmission system 110 may be configured with a shared authentication key, which may be used in conjunction with the shared secret value in a cryptographic algorithm to generate a message authentication code. In other embodiments, the transmission system may instead be configured with a shared authentication master key, which may be used to dynamically generate a shared authentication key when needed. The resulting shared authentication key may then be used in conjunction with the shared secret value in a cryptographic algorithm to generate a message authentication code. One or more other shared or determinable communication parameters (e.g., the counter described above) may be used to generate the shared authentication key, the message authentication code, or both.

[0037] In some embodiments, rather than being configured with a static shared secret value, the transmission system 110 is configured with a shared secret master key, which may be used to dynamically generate a shared secret value when needed. The shared secret master key may be stored in a memory included in or accessible to the transmission system 110 when constructing a message. At this time, the transmission system 110 may obtain the shared secret master key and combine it with one or more fixed parameters (e.g., a fixed identifier or account associated with the transmission system 110) and / or one or more variable parameters (e.g., an encrypted transmission counter) in a cryptographic algorithm to generate a shared secret value. The resulting shared secret value may then be used, as described above, to construct a message authentication code.

[0038] Once generated, the message authentication code may be added to the sensitive data portion of the message to be transmitted before encrypting the sensitive data portion using the symmetric key. Alternatively, the message authentication code may be encrypted separately to generate a message authentication code ciphertext that may be added to the message before transmission. The transmission system 110 may then send a message including encrypted and unencrypted information to the receiving system 120.

[0039] The receiving system 120 can be configured to receive and process messages transmitted by the transmitting system 110. This can include initially processing unencrypted information, which, as previously mentioned, can include information sufficient for the receiving system 120 to identify the transmitting system 110. It can also include deriving one or more communication parameters, which can be included for use in decrypting encrypted message information. In a particular embodiment, the receiving system 120 can be configured to determine a symmetric session key used to encrypt the encrypted message information. As previously mentioned, the receiving system 120 can be configured with the same secret master key as the transmitting system. Thus, the receiving system 120 can be configured to use the same symmetric cryptographic algorithm as the transmitting system to establish a secret session key using the secret master key. In embodiments where additional parameters are used in the construction of the session key, the receiving system can also be configured to determine these parameters. In some embodiments, one or more such parameters can be included in the unencrypted portion of the received message. In other embodiments, parameters such as an encrypted communication counter can be determined in parallel by the receiving system 120.

[0040] The receiving system 120 can also be configured to use the constructed symmetric encryption session key to decrypt the encrypted portion of the message. In embodiments where a message authentication code is included as additional ciphertext, the receiving system 120 can also separately decode the ciphertext. In either case, the receiving system 120 can also be configured to authenticate the received message using the decrypted message authentication code. To achieve this, the receiving system 120 can obtain or generate a shared secret value associated with the receiving system and the transmitting system 110. In some embodiments, the receiving system 120 can have a static shared secret value associated with the identification information of the transmitting system 110 or an account associated with the transmitting system. In such embodiments, the receiving system 120 can use the identification information provided in the received message to obtain the shared secret value from a database stored in or accessible by the receiving system 120. In other embodiments, the receiving system 120 may need to use a copy of the shared secret master key to generate the shared secret value. In such embodiments, the receiving system 120 can use the transmitting system identification information to obtain the shared secret master key rather than the shared key itself. Then, the receiving system 120 can use the shared secret master key to generate the shared secret value in the same manner as the transmitting system 120.

[0041] Then, the resulting shared secret value can be used as a salt value to generate an authentication code for the confirmation message using the same encryption algorithm as used by the transmission system 110. In some embodiments, the receiving system 120 can obtain the shared authentication key from memory, and the shared authentication key can be used together with the shared secret value in the encryption algorithm to generate an authentication code for the confirmation message. In other embodiments, the receiving system 120 can instead obtain the shared authentication master key associated with the transmission system 110 or an account associated with the transmission system 110. Then, the shared authentication master key can be used to generate the shared authentication key. Then, the resulting shared authentication key can be used together with the shared secret value in the cryptographic algorithm to generate an authentication code for the confirmation message. According to an embodiment, one or more other shared or determinable communication parameters (e.g., the counter described above) can be used to generate the shared authentication key, the authentication code for the confirmation message, or both. Once generated, the authentication code for the confirmation message can be compared with the decrypted authentication code to authenticate the message.

[0042] Referring to Figure 2 , a data transmission system 200 according to an exemplary embodiment can include a transmitting or sending data processing system 210, a receiving or receiving data processing system 220, which communicate with each other via a network 230 and communicate with one or more servers 250. The system 200 also includes a key generation and control system 240 configured to communicate via the network 230. Each of the transmitting and receiving data processing systems 210, 220 can be or include any network-enabled processor computer system or device, including but not limited to any server, network device, personal computer (PC), workstation, mobile processing device such as a smart phone, smart board, handheld PC, or personal digital assistant (PDA), or a card-mounted microprocessor capable of directly or indirectly communicating over a network.

[0043] Network 230 can be or include a wireless network, a wired network, or any combination of a wireless network and a wired network, and can be configured to connect one or more transmission systems 210 and one or more receiving systems 220 to server 250. Network 230 can include, for example, a fiber optic network, a passive optical network, a cable network, an Internet network, a satellite network, a wireless LAN, a Global System for Mobile Communications (GSM), a Personal Communications Service (PCS), a personal area network, a Wireless Application Protocol (WAP), a Multimedia Messaging Service (MMS), an Enhanced Messaging Service (EMS), a Short Message Service (SMS), a Time Division Multiplexing (TDM)-based system, a Code Division Multiple Access (CDMA)-based system, D-AMPS, Wi-Fi, fixed wireless data, IEEE 802.11b, 802.15.1, 802.11n, and 802.11g, Bluetooth, Near Field Communication (NFC), Radio Frequency Identification (RFID), Wi-Fi, etc.

[0044] In addition, network 230 can include, but is not limited to, a telephone line, fiber optic, IEEE Ethernet 902.3, a Wide Area Network (WAN), a wireless personal area network, a Local Area Network (LAN), or a global network such as the Internet. Additionally, network 230 can support an Internet network, a wireless communication network, a cellular network, etc., or any combination thereof. Network 230 can also include one network, or any number of the above-exemplified types of networks, operating as a stand-alone network or in cooperation with each other. Network 230 can utilize one or more protocols of one or more network elements to which it is communicatively coupled. Network 230 can convert other protocols into one or more protocols of network devices, or from other protocols into one or more protocols of network devices. Although network 230 is depicted as a single network, it should be understood that, according to one or more examples, network 230 can include multiple interconnected networks, such as, for example, the Internet, a service provider's network, a cable television network, a corporate network such as a credit card association network, and a home network.

[0045] In some examples, one or more transmission systems 210 and one or more receiving systems 220 can be configured to communicate with each other, with the key generation and control system 240 and / or server 250 without going through network 230. For example, the key generation and control system 240 can be configured to communicate with the sending data processing system 210 via communication link 232, which can be or include one or more of a dedicated network, near field communication, Bluetooth, radio frequency identification, Wi-Fi, etc.

[0046] In various embodiments, the transmit and receive data processing systems 210, 220 may be similar to those described above with respect to the data transmission system 100. Specifically, the transmit data processing system 210 and the receive data processing system 220 may each be configured to obtain or generate a shared encryption key, which may be used to generate a shared session key that is used to encrypt and decrypt the message content transmitted over the network 230. Additionally, each of the transmit data processing system 210 and the receive data processing system 220 may be configured to obtain or generate a shared key and to obtain and generate a shared authentication key, which may be used to generate a message authentication code.

[0047] However, in the system 200, some or all of the master keys that are used to generate the parameters specific to generating a shared session key for a particular communication may be generated and shared by the key generation and control system 240. In an exemplary embodiment, the key generation and control system 240 may be configured to generate one or more of an encryption master key, a shared secret master key, and an authentication master key. Each of these may be associated with the identification information of the transmit system 210 or with an account associated with the transmit processing system 210. In some embodiments, any one or all of these keys may then be sent to the transmit processing system 210, which stores them for future use in generating encrypted communications. However, in some embodiments, the key generation and control system 240 may use the shared secret master key and the transmit system identifier to generate a shared key, which is then sent to or directly saved in the memory in the transmit system 210. In a particular embodiment, the key generation and control system 240 may transmit one or more master keys and / or shared keys to the transmit data processing system 210 via a dedicated communication link 232. In some examples, this may be done during the system provisioning process. In some embodiments, the key generation and control system 240 may associate each master key with a plurality of transmit data processing systems 210 and their unique identifiers. In this way, a single shared secret master key may be combined with any one of a plurality of transmit system identifiers to generate a transmit system-specific shared key.

[0048] The key generation and control system 240 can transmit any one or all of the encrypted master key, the shared secret master key, and the authentication master key, as well as the identification information for the transmission data processing system 210, via the network 230. One or more receiving data processing systems 220 can then store the one or more keys and the identification information in an accessible data memory. In a particular example, the key generation and control system 240 can send a copy of the shared secret master key and the identifier for the transmission data processor to the receiving data processor 220, which can place them in the memory. The receiving system 220 can be configured to generate a session key and decrypt the encrypted portion of the message when receiving a message with encrypted information from the transmission system 210, obtain the shared secret master key and use it together with the identifier (or other appropriate identification information) to generate a shared key, and further generate a confirmation message authentication code for comparison with the decrypted message authentication code in the received message.

[0049] System 200 provides a basis for authenticating messages using a shared key without requiring the entity responsible for configuring the transmission system to transmit the shared key in plaintext to potential receiving systems. As previously mentioned, this approach can be particularly valuable in the field of card-based transactions. In this regard, the sending / transmission processing system can be a microprocessor installed on the card, and the receiving processing system can be the receiving / authentication gateway of the card transaction processing system.

[0050] Referring to Figures 3 - 8 , the transaction card communication system 300 includes a transaction card 320 associated with a user account. The transaction card 320 can be one of multiple cards distributed by an issuer for conducting financial transactions through one or more transaction processing entities. The system 300 includes an issuer processing system 350 managed by the issuer and one or more card message processing systems 360 managed by one or more transaction processing entities. The system 300 can also include one or more user devices 310, each user device associated with a user who may be associated with a user account. The system 300 can also include one or more transaction processors 340 configured to facilitate financial transactions involving the transaction card 320. Each of the user devices 310, the transaction processors 340, the issuer processing system 350, and the card message processing systems 360 can be or include a network-enabled data processing system configured to selectively communicate via the network 330.

[0051] Network 330 may be or include a wireless network, a wired network, or any combination of a wireless network and a wired network, and may be configured to connect one or more transmission systems (e.g., user device 310 and transaction processor 340) and one or more receiving systems (e.g., card message processing system 360) to various servers and systems (e.g., issuer processing system 350). Network 330 may include, for example, a fiber optic network, a passive optical network, a cable network, an Internet network, a satellite network, a wireless LAN, a Global System for Mobile Communications (GSM), a Personal Communications Service (PCS), a personal area network, a Wireless Application Protocol (WAP), a Multimedia Messaging Service (MMS), an Enhanced Messaging Service (EMS), a Short Message Service (SMS), a Time Division Multiplexing (TDM)-based system, a Code Division Multiple Access (CDMA)-based system, D-AMPS, Wi-Fi, fixed wireless data, IEEE 802.11b, 802.15.1, 802.11n, and 802.11g, Bluetooth, Near Field Communication (NFC), Radio Frequency Identification (RFID), Wi-Fi, etc.

[0052] In addition, network 330 may include, but is not limited to, a telephone line, fiber optic, IEEE Ethernet 902.3, a Wide Area Network (WAN), a wireless personal area network, a Local Area Network (LAN), or a global network such as the Internet. In addition, network 330 may support an Internet network, a wireless communication network, a cellular network, etc., or any combination thereof. Network 330 may also include one network, or any number of the above-exemplified types of networks, operating either independently or in cooperation with each other. Network 330 may utilize one or more protocols of one or more network elements to which it is communicatively coupled. Network 330 may convert other protocols into one or more protocols of a network device, or from other protocols into one or more protocols of a network device. Although network 330 is depicted as a single network, it should be understood that, according to one or more examples, network 230 may include multiple interconnected networks, such as, for example, the Internet, a service provider's network, a cable television network, a corporate network such as a credit card association network, and a home network.

[0053] The transaction card 320 used in the embodiments of the present invention may include a chip-bearing transaction card (“smart” card) having electrical and / or near-field or other short-range communication capabilities. As Figure 3 and Figure 4As shown, a typical transaction card 320 that can be used in various embodiments of the present invention is a smart card having a microprocessor chip 321. The microprocessor chip 321 includes processing circuitry for storing and processing information, including a microprocessor 322 and a memory 326, and may also include a power management system 325. It should be understood that the processing circuitry may include additional components as required to perform the functions described herein, and such additional components include a processor, a memory, an error and parity / CRC checker, a data encoder, an anti-collision algorithm, a controller, a command decoder, security primitives, and tamper-resistant hardware.

[0054] The transaction card 320 is configured to communicate with a transaction processor and other devices via a terminal communication interface 324. The interface 324 and the microprocessor 322 may be specifically configured to establish communication with a merchant transaction processing device 340 to perform purchases and other transactions. The communication interface 324 may be configured to provide contact-based communication, in which case the interface 324 may have circuitry and contact pads on the surface of the card 320 for establishing direct electrical communication between the microprocessor 322 and the processing circuitry of the transaction terminal 340. Alternatively or additionally, the first communication interface 324 may be configured for non-contact communication with the transaction terminal 340. In such an embodiment, the communication interface 324 may be or include an NFC communication interface that is configured to communicate with other NFC communication devices when the card 320 is within a predetermined NFC range. The communication interface 324 and the microprocessor 322 may also be configured to establish NFC communication with the user device 310. In some embodiments, the microprocessor chip 321 may include a second communication interface 328 that is configured to establish short-range communication with the user device 310 via Bluetooth or other short-range communication methods. In such an embodiment, the transaction card 320 may have a short-range communication antenna 329 that is included in or connected to the short-range communication interface 328.

[0055] In a particular embodiment, the transaction card 320 may implement Bluetooth functionality using the microprocessor chip 321, the second communication interface 328, and the antenna 329. The transaction card implementing Bluetooth functionality may support Bluetooth Low Energy (BLE) and may be paired with the user device 310. In some embodiments, pairing and communication may be established between the transaction card 320 and other interface devices such as a terminal (not shown), a merchant transaction processor 340, etc. The device implementing Bluetooth functionality may include the ability to establish a link (or pair the device) between the card and the device using device settings (e.g., iOS or Android settings for managing Bluetooth connections) and / or a mobile application associated with an issuing institution that can cooperate with the device control to manage the Bluetooth connection with the card 320.

[0056] The memory 326 can be a read-only memory, a write-once read-many memory, or a read / write memory (such as RAM, ROM, and EEPROM), and the chip 321 can include one or more of these memories. The memory 326 can store therein information associated with the transaction card account. In some embodiments, the memory 326 can permanently store therein a unique alphanumeric identifier associated with the account. It can also permanently store public and private card encryption keys. In some embodiments, the private and public encryption keys can be permanently hardwired into the card memory.

[0057] The memory 326 can be configured to store one or more software applications for execution by the microprocessor 322. In a particular embodiment, the card memory 326 has stored therein a transaction processing application that is configured to perform financial transactions at the merchant terminal 340 or via the user device 310. The application includes instructions for the microprocessor 322 to establish communication with the transaction terminal 340 or the user device 310. For transaction terminal interaction, communication can be established when the transaction card 320 is introduced into the transaction terminal 340 by inserting the card 320 for electrical contact, by bringing the card 320 within the NFC communication range of the transaction terminal 340, or by tapping the transaction card 320 against the transaction terminal 340. For user device interaction, communication can be established by bringing the card 320 within the NFC communication range of the user device 310, or by tapping the transaction card 320 against the user device 310. The application instructions can be configured to cause the microprocessor 322 to receive information related to the financial transaction from the transaction terminal 340 via the first communication interface 324. Such transaction information may include the type of transaction (e.g., purchase, refund, transfer, account payment, etc.) and the monetary value. The transaction information can also include information about the terminal 340 and / or the entity managing the terminal 340. Such information can include, for example, the terminal or merchant identifier and / or location information.

[0058] In various embodiments, the memory 326 can store therein instructions for generating an encrypted communication that is transmitted via a network-enabled intermediate device (such as the user device 310 or the transaction processor 340) to the remote card messaging system 360. In a particular example, these instructions can be configured to construct a transaction message having an encrypted portion and an unencrypted portion and including a message authentication code.

[0059] To prepare a transaction message, an application can be configured to use a card unique key (referred to herein as the unique derived key or UDK) and an appropriate symmetric cryptographic algorithm to establish a secret session key for encrypting sensitive message content. In some embodiments, the UDK can be stored in the memory 326 and the UDK can be retrieved from the memory 326 for use. In other embodiments, the UDK can be generated using a UDK master key retrieved from the memory 326 and a card identifier retrieved from the memory 326 when needed. In some embodiments, additional parameters can be used in the construction of the shared symmetric session key. An example is a counter that is updated each time an encrypted communication of the card message processing system 360 is encrypted and transmitted. In some embodiments, the counter or other parameters can be included in the encrypted transmission and / or included in an unencrypted attachment along with the encrypted transmission.

[0060] The symmetric algorithm used can include any symmetric cryptographic algorithm capable of generating a diversified symmetric key of a desired length. Non-limiting examples of symmetric algorithms can include symmetric encryption algorithms such as 3DES or AES128, symmetric HMAC algorithms such as HMAC-SHA-256; and symmetric CMAC algorithms such as AES-CMAC. It should be understood that if the output of the selected symmetric algorithm does not generate a key of sufficient length, techniques such as multiple iterations of processing the symmetric algorithm with different input data and the same master key may generate multiple outputs that can be combined as needed to generate a key of sufficient length.

[0061] The encryption application can be configured to use the constructed symmetric encryption session key to process some or all of a set of information for transmission to the card message processing system 360. For example, the microprocessor 322 can encrypt the sensitive part of the data using a symmetric encryption algorithm and the session key, and the output includes an encrypted information set. Then, the microprocessor can send a message via the terminal communication interface 324 or the short-range communication interface 328, and the message includes the encrypted information set that will be relayed to the card message processing system 360 via the network 330. The message can also include unencrypted information, which can include, for example, a card identifier and / or transaction-related information. In a particular embodiment, additional communication parameters (e.g., a counter) can be included.

[0062] In certain embodiments, the transaction message can include a message authentication code generated using a shared secret value. In some embodiments, the card 320 can be configured with an assigned shared secret value that can be stored in the memory 326 when the card is issued. The encryption application can be configured to obtain the stored shared secret value from the memory 326 when constructing a message for transmission to the card message processing system 360. The shared secret value can then be used as a salt value in any known encryption algorithm to generate the message authentication code. In some examples, one or more other shared or determinable communication parameters (e.g., an encrypted communication counter) can be used with the shared secret value to generate the message authentication code.

[0063] In some embodiments, the transmission system 110 is not configured with a static shared secret value, but rather with a shared secret master key that can be used to dynamically generate a shared secret value when needed. The shared secret master key can be stored in the memory 326 when configuring the transaction card 320. The encryption application can be configured to obtain the shared secret master key and combine it with the card identifier or other fixed card parameters in an encryption algorithm to generate the shared secret value. The resulting shared secret value can then be used to construct the message authentication code. In some examples, one or more other shared or determinable communication parameters (e.g., an encrypted communication counter) can be used with the shared secret master key and the card identifier to generate the shared key.

[0064] In some examples, the message authentication code can be included in the sensitive data portion encrypted using the session key described above. However, in some embodiments, the message authentication code can be encrypted separately to generate a card authentication code ciphertext that can be appended to the message. In some embodiments, the same session key used to encrypt the sensitive portion of the message can be used to generate the ciphertext. However, in other embodiments, the message authentication code can be encrypted using a second shared session key generated using a second UDK. The second UDK can be stored in the memory 326 when configuring the card 320, or the second UDK can be dynamically generated from a second UDK master key stored in the card memory 326 when needed. In either case, the second UDK can be combined with the card identifier to generate a second session key that can be used to encrypt the message authentication code to generate the message authentication code ciphertext. The ciphertext can then be appended to the transaction message, which can then be sent to the card message processing system 360.

[0065] Referring to Figure 5, the account holder or user device 310 can be any networked data processing and / or communication device used by the account holder to perform transactions and / or receive notifications from the transaction processor, including but not limited to smartphones, laptops, desktop computers, and tablet computers. In a particular embodiment, the account holder device 310 includes an on-board data processor 311 that communicates with a memory module 313, a user interface 314, and a network communication interface 312. In some embodiments, the account holder device 310 may include an image capture device (e.g., a digital camera). The data processor 311 may include a microprocessor and associated processing circuitry, and may include additional components required to perform the functions described herein, the additional components including a processor, a memory, an error and parity / CRC checker, a data encoder, an anti-collision algorithm, a controller, a command decoder, security primitives, and tamper-proof hardware. The memory 313 may be a read-only memory, a write-once read-many memory, or a read / write memory (e.g., RAM, ROM, and EEPROM), and the user device 310 may include one or more of these memories.

[0066] The user interface 314 includes a user input mechanism, which can be any device for inputting information and instructions into the account holder device 310 (such as a touch screen, a keyboard, a mouse, a cursor control device, a microphone, a stylus, or a digital camera). The user interface 314 may also include a display, which can be any type of device for presenting visual information, such as a computer monitor, a flat panel display, and a mobile device screen, including a liquid crystal display, a light emitting diode display, a plasma panel, and a cathode ray tube display.

[0067] The network communication interface 312 can be configured to establish and support wired or wireless data communication capabilities to connect the device 310 to the network 330 or other communication networks. The user device 310 may also have an NFC communication interface 319, which can be configured to support short-range wireless communications such as near field communication (NFC), radio frequency identification, and Bluetooth. The NFC interface 319 can be particularly configured to establish near field communication with the data processing chip 321 on the transaction card 320 and to receive information sent by the data processing chip 321 via the chip NFC interface 324.

[0068] In an embodiment of the present invention, the memory 313 may store one or more applications therein, which may be used by the data processor 311 to conduct and / or monitor transactions between the user device 310, the transaction processor 340, and other transaction processing systems. These applications may include instructions that the data processor 311 can use to identify transaction events, store event data in the memory 313, and transmit the event data. In some embodiments, they may include instructions for receiving transaction messages from the transaction card 320 and transmitting these messages via the network 330 to the card message processing system 360. The application may be configured to instruct the data processor 311 to interpret some or all of the unencrypted portions of the messages.

[0069] Referring Figure 6 , the transaction processor (TPM) 340 may be any networked processor configured to handle transactions involving the transaction card 320. The TPM 340 may be, for example, a cash register, an automated teller machine, a vending machine, or other POS terminal capable of communicating with the transaction card 320 and capable of communicating with the card message processing system 360 via the network 130. In some embodiments, the TPM 340 may include a TPM data processor 341, a network communication interface 342, a TPM user interface 344, a memory 343, and a card communication interface 346.

[0070] The TPM data processor 341 may include a microprocessor and associated processing circuitry, and may contain additional components required to perform the functions described herein, the additional components including a processor, a memory, an error and parity / CRC checker, a data encoder, an anti-collision algorithm, a controller, a command decoder, security primitives, and tamper-resistant hardware. The memory 343 may be a read-only memory, a write-once read-many memory, or a read / write memory (such as RAM, ROM, and EEPROM), and the transaction processor 340 may include one or more of these memories.

[0071] The TPM user interface 344 may include a user input mechanism, which may be any device for inputting information and instructions into the TPM 340 (such as a touch screen, a keyboard, a mouse, a cursor control device, a microphone, a stylus, or a digital camera). The user interface 344 may also include a display, which may be any type of device for presenting visual information, such as a computer monitor, a flat panel display, and a mobile device screen, including a liquid crystal display, a light-emitting diode display, a plasma panel, and a cathode ray tube display.

[0072] The network communication interface 342 can be configured to establish and support wired or wireless data communication capabilities for connecting the machine 340 to the network 330 or other communication networks. The card communication interface 346 can be configured to receive the transaction card 320 and make electrical contact for wired communication between the TPM data processor 341 and the transaction card processor 321. Alternatively or additionally, the card communication interface 346 can be configured to support short-range wireless communication such as near field communication (NFC), radio frequency identification, and Bluetooth between the transaction card 320 and the TPM data processor. The card communication interface 346 can be specifically configured to establish wired or wireless communication with the data processing chip 321 on the transaction card 320 and to receive information transmitted by the data processing chip 321 via the chip terminal communication interface 324.

[0073] In an embodiment of the present invention, the TPM memory 343 can store one or more applications therein, and these applications can be used by the data processor 341 to conduct transactions and communicate with the transaction processing system. These applications can include instructions that the data processor 341 can use to identify transaction events, store event data in the memory 343, and transmit the event data. In some embodiments, they can include instructions for receiving transaction messages from the transaction card 320 and transmitting these messages via the network 330 to the card message processing system 360. The application can be configured to instruct the data processor 341 to interpret some or all of the unencrypted portions of the messages.

[0074] The card issuer processing (CIP) system 350 can be associated with a transaction card issuer, and the transaction card issuer can provide and distribute a large number of transaction cards 320, and each transaction card 320 is associated with one or more user accounts. The card issuer can be or can be directly associated with the administrator of such user accounts, or can be a separate contracting entity. In either case, the card issuer can utilize the card issuer processing system 350 to configure applications and data for the transaction card 320 to perform secure communication according to embodiments of the present invention.

[0075] Referring to Figure 7 , the CIP system 350 is a networked automatic data processing system. The CIP system 350 can include a card distribution processor 353, an encryption key generation processor 354, a shared key generation processor 355, and a key distribution processor 356. The CIP system 350 can also include a card communication interface 352 configured to communicate with the transaction card 320 in a wired or wireless manner, and a network communication interface 351 configured to establish communication with the network 330 and / or other networks. In some embodiments, the CIP system 350 can include a card database 359. In other embodiments, the card database 359 can be separated from the CIP system 350, but can be accessed by the CIP system 350.

[0076] The card communication interface 352 is configured to allow one or more configuration processors 353, 354, 355 to transfer information directly into the memory 326 of the transaction card 320. This can be achieved by direct electrical / data communication via electrical contacts on the card chip 321. Alternatively or additionally, the card communication interface 352 can be configured to communicate with the card chip 321 via the card's terminal communication interface 324 or short-range communication interface 328 in a contactless manner. In such an embodiment, the card communication interface 352 can be or include an NFC communication interface that is configured to communicate when the card 320 is within a predetermined NFC range. The card communication interface 352 can also be configured to establish short-range communication via Bluetooth or other short-range communication methods.

[0077] The CIP system 350 can include one or more automatic data processors that are configured to configure the microprocessor chips 321 of a plurality of transaction cards 320. In some embodiments, this can include a card distribution processor 353 that is configured to establish wired or wireless communication with the chip 321 of the card 320 via the card communication interface 352. The card distribution processor can also be configured to generate or otherwise determine one or more card identifiers of the card 320 and transmit these card identifiers to the memory 326 of the card 320 for storage or otherwise permanently store them in the memory 326 of the card 320. The card distribution processor 353 can also store one or more identifiers in a record in the card database 359.

[0078] One or more of the automatic data processors of the CIP system 350 may also include an encryption key generation processor 354. The processor 354 may be configured to generate encryption keys that may be used by the card microprocessor 322 to encrypt message content. In a particular embodiment, the encryption key generation processor 354 may be configured to generate one or more UDK master keys, each of which may be combined with one of one or more card identifiers to generate a card-unique UDK. The UDK master keys may be generated using any secure random or pseudo-random number generator. Each UDK master key may be associated with or included in a card record stored in the card database 359. In some embodiments, each UDK master key may be associated with the unique identifier of multiple transaction cards 320. In such embodiments, the UDK master keys may be stored separately and associated with only a single card record. In some embodiments, the encryption key generation processor 354 may transmit one or more UDK master keys to the memory 326 of the card 320 for storage or otherwise permanently store them in the memory 326 of the card 320. In such embodiments, the card microprocessor 322 may use each UDK master key to generate a card-unique UDK, which may then be used to generate a communication session key for encryption. In other embodiments, the encryption key generation processor 354 itself may use the card-associated UDK master key in combination with the card identifier to generate a card-unique UDK, which is then transmitted to the memory 326 of the card 320 for storage or otherwise permanently store it in the memory 326 of the card 320. In such embodiments, the card microprocessor 322 will not need to regenerate the UDK for each communication. It only needs to obtain the UDK from the memory 326.

[0079] One or more automatic data processors of the CIP system 350 may also include a shared key generation processor 355. The shared key generation processor 355 may be configured to generate a shared secret master key, which may be combined with one of the one or more card identifiers to generate a shared secret value for the card 320. The shared secret master key may be generated using any secure random number or pseudo-random number generator. The shared secret master key may be associated with or included in the card record stored in the card database 359. In some embodiments, the shared secret master key may be associated with the unique identifiers of multiple transaction cards 320. In such embodiments, the shared secret master key may be stored separately and associated with only a single card record. In some embodiments, the shared key generation processor 355 may transmit the shared secret master key to the memory 326 of the card 320 for storage or otherwise permanently store it. In such embodiments, the card microprocessor 322 may use the shared secret master key in combination with one of the one or more card identifiers to generate a card-unique shared secret value, which may then be used to generate the message authentication code as described previously. In other embodiments, the shared key generation processor 355 itself may use the shared secret master key in combination with the card identifier to generate a shared secret value, which is then stored in the memory 326 of the card 320 for storage or otherwise permanently stored in the memory 326 of the card 320. In such embodiments, the card microprocessor 322 will not need to regenerate the shared key for each communication. It only needs to obtain the shared key from the memory 326. In all embodiments, the shared secret master key may be associated with or included in the card record of the card 320 stored in the card database 359.

[0080] The CIP system 350 may further include a key distribution processor 356 configured to communicate with one or more card message processing systems 360 via the network communication interface 351 and the network 330. The key distribution processor 356 may be configured to obtain card information from the card records of each card 320 and transmit it to some or all of the card message processing systems 360. Such card information may include one or more unique card identifiers, one or more UDK master keys associated with the card 320, and a shared secret master key. In embodiments where a master key is associated with multiple card identifiers, the master key may not be included in a separate card record. In such embodiments, the master key may be transmitted separately from the card record. In certain embodiments, the key distribution processor 356 may be configured to send a single instance of each master key and the identifiers of all cards 320 associated with those master keys. The key distribution processor 356 may also be configured to identify or provide a copy of the algorithm for generating the UDK and the shared key from their respective master keys. In some embodiments, the transmission of the card information may occur in response to a request for card information from the card message processing system 360. The key distribution processor 356 may be configured to receive, evaluate, and verify such a request and transmit the card information only when it has verified the authorization of the card message processing system 360 to receive such information for a particular card (or cards) 320.

[0081] The card message processing (CMP) system 360 may be associated with a transaction processor, a card transaction administrator, or other entities authorized to receive communications transmitted by the transaction card 320 via an intermediate device (e.g., the user device 310 or the transaction processor 340). Referring to Figure 8, the CMP system 360 may include a network communication interface 361 configured to selectively communicate via network 330 and / or other networks. A card record management system 362 may be configured to receive card information of one or more transaction cards 320 from the CIP system 350 and store such information in a card database 369. Each card record in the database 369 may include, but is not limited to, one or more unique card identifiers, one or more UDK master keys, and a shared secret master key. In some embodiments, each card record may further include an encrypted communication counter. In some embodiments, the card record may include a master key index reference instead of the actual UDK and shared secret master key to allow retrieval of the master key associated with a particular card from a separate storage medium (e.g., in another encrypted information database or within a security module of the CMP system 360). In embodiments where the UDK and shared secret master key are associated with the card identifiers of multiple transaction cards 320, the card record may include only an indication of the association of such master key with one or more unique card identifiers. In a particular embodiment, the stored master keys may include a first UDK master key for generating a UDK for decrypting message content and a second UDK master key for generating a UDK for decrypting message authentication code ciphertext.

[0082] The CMP system 360 may also include one or more automatic data processors configured to receive and decrypt messages received from the transaction card 320. These one or more communication interpretation processors may include a transaction message receiving data processor 363 configured to receive and evaluate each message. This may include interpreting unencrypted information that may include, for example, identification information (e.g., a unique card identifier) sufficient to identify the particular card 320 from which the communication was received. In some embodiments, the unencrypted information may include an encrypted communication counter value or information from which such a counter may be derived.

[0083] One or more communication interpretation processors of the CMP system 360 may also include a decryption processor 364 configured to decrypt at least a portion of the decrypted information in the received message. This may include obtaining a first UDK master key of the card 320 from the card database 369 (or other storage location) and using the first UDK master key in combination with an appropriate card identifier to generate a first UDK. The first UDK may then be used to create a first session key for decrypting at least a portion of the encrypted content of the received message. The decrypted information may be or include sensitive transaction information that may be stored and / or transmitted to the transaction processing system 366. In some embodiments, the decryption processor 364 may be configured to update an encrypted message counter associated with the transaction card 320. The counter may then be compared with the counter value received in the message and / or used as a shared parameter in any key or shared key generation algorithm.

[0084] As previously described, in certain embodiments, the message portion including sensitive information encrypted with a particular session key may also include a message authentication code encrypted with the same session key. In such embodiments, the decryption processor 364 may transmit the decrypted method authentication code to the authentication processor 365 for authenticating the message. However, in other embodiments, the method authentication code may be encrypted separately and the resulting ciphertext is appended to the encrypted message. In such embodiments, the decryption processor 364 may be configured to obtain a second UDK master key of the card 320 from the card database 369 (or other storage location) and use the second UDK master key in combination with an appropriate card identifier to generate a second UDK. The second UDK may then be used to create a second session key for decrypting the method authentication code ciphertext. The decrypted method authentication code may then be transmitted to the authentication processor 365.

[0085] The authentication processor 365 may be configured to authenticate the received message based on a comparison of decryption parameters with the unencrypted information received in the message and / or information stored on the card record of the card 320. In a particular embodiment, the authentication processor 365 may be configured to generate a method authentication code based on known parameters of the card 320 and compare it with the decrypted method authentication code in the received message. In doing so, the authentication processor 365 may obtain a shared secret master key from memory and use it in combination with an appropriate card identifier and an appropriate diversification algorithm to generate a shared key. In certain embodiments, the generation of the shared key may also require one or more additional shared parameters (e.g., the encrypted message counter). In such embodiments, the authentication processor 365 may also be configured to obtain or otherwise determine the one or more additional shared parameters required for generating the shared key.

[0086] The authentication processor 365 may also be configured to generate a method authentication code using the generated shared key and an appropriate algorithm and compare it with the decrypted method authentication code from the message. A match indicates the authenticity of the message and its source. If the codes do not match, the authentication processor 365 may send an error message to the transaction processing system 366 and / or the intermediate device (e.g., the user device 310 or the transaction processor 340) through which the transaction card 320 sent the message. The authentication processor 365 may also terminate further processing of the message and any related transactions. It may also decrement the encrypted message counter.

[0087] The authentication processor may be configured to convey the authentication result to the transaction processing system 366. In some embodiments, the transaction processing system 366 may be configured to process the information in the received message to initiate or complete a transaction. In other embodiments, the transaction processing system 366 may be configured to construct a transaction processing request and transmit it to a transaction processing institution or other financial entity for processing.

[0088] Figure 9 An operational sequence in an illustrative use of the transaction card communication system 300 is schematically shown. At 1100, the card issuer processing system generates a key and / or a shared key for a particular transaction card as part of the card configuration process. The generated keys include one or more UDK master keys and a shared secret master key. In embodiments where the shared key will be statically stored in the card memory, the card issuer may generate the shared key based on the shared secret master key and the card identifier. At 1200, the card issuer processing system provides the transaction card with the transaction card identifier and one or more UDK master keys. It also provides the card with the shared secret master key or the shared key itself.

[0089] At 1300, the card issuer processing system sends the card information to the card message processing system. The information may include the card identifier, one or more UDK master keys, and the shared secret master key. In embodiments where each master key may be used in combination with the card identifiers of multiple cards, the card issuer may send a single instance of each master key and the identifiers of all the cards associated with those master keys. At 1400, the card message processing system stores some or all of the card records in the card database for use in interpreting messages from the transaction card in the future.

[0090] At some point after configuration, the card is issued for use by the account holder. At 1500, as part of the transaction encounter, the transaction card microprocessor constructs a message to transmit to the card message handling system. In doing so, the card microprocessor can obtain the shared key from the card memory, or obtain the shared secret master key and use it to generate the shared key, as described previously. The shared key can then be used to generate a message authentication code. The card microprocessor can then obtain the first UDK master key and use it to generate a first UDK, which in turn can be used to generate a session key for encrypting at least a portion of the message. In some embodiments, the card microprocessor can also obtain a second UDK master key for generating a second UDK for encrypting the message authentication code.

[0091] At 1600, the transaction card transmits the message to an intermediate device with which the card is interacting to perform the transaction, and retransmits it to the card message handling system. Depending on the circumstances, the intermediate device can be, for example, the account holder's mobile device or the merchant's transaction processor. The message can be transmitted via direct electrical contact or via NFC or other short-range communication modes. At 1700, the intermediate device sends the message to the card message handling system.

[0092] At 1800, the card message handling system receives and processes the message. This may include identifying the card based on the unencrypted content of the message, and based on that identification, obtaining the card's decryption information from the card database. In particular, the card message handling system can obtain the first UDK master key and (if appropriate) the second UDK master key and use them to generate the keys required to decrypt the encrypted content and the method authentication code. The card message handling system then decrypts the message and the message authentication code. The shared secret master key is then obtained and used to generate a shared key, which is then used to generate a message authentication code value for comparison with the code obtained from the message to authenticate the message and its source.

[0093] Now referring to Figure 10 , method M100 for facilitating the authentication of encrypted messages will be described. Method M100 can be performed by a network-supported key generation and control system (such as the system 240 shown in Figure 2 or the issuer processing system 350 of Figure 3 ). At S110 of method M100, the key generation and control system can generate one or more encryption master keys for generating encryption and session keys for encrypting messages to be sent from a sending data processing system to a receiving data processing system. These master keys can be, for example, generated by Figure 3 and 4The UDK master key used by the transaction card 320. At S120, the key generation and control system can generate a shared secret master key for generating a shared secret value that can be used to generate a message authentication code. In some embodiments, the system can optionally use the shared secret master key and a predefined shared key generation algorithm to generate an actual shared key. In a particular embodiment, the shared key generation algorithm may need to use an identifier or other unique information associated with the transmission processing system. The key generation and control system can use an existing identifier or establish an identifier for the transmission processing system. In an embodiment where the sending data processing system is the microchip of the transaction card, the identifier can be the card number or other card-unique identifier. At S140, the key generation and control system can associate the encryption master key(s) and the shared secret master key with the identifier of the transmission system and store the keys and the identifier in the encrypted key database.

[0094] At S150, the key generation and control system provides one or more encryption master keys, the shared secret master key, or the shared key itself to the first communication system (i.e., the sending data processing system). A specific key generation and / or encryption algorithm can also be identified or provided. In an embodiment where the first communication system is a transaction card, the master key, algorithm, and / or shared key can be directly stored in the card memory or transmitted to the card microprocessor as part of the card configuration process. In other embodiments, the master key and algorithm identifier (or algorithm) can be transmitted over the network to the first communication data processing system. In an embodiment where the encrypted information is transmitted over the network, the shared secret itself is preferably not transmitted.

[0095] At S150, the key generation and control system sends one or more encryption master keys, the key generation and encryption algorithms, and the shared secret master key to the second communication system (i.e., the receiving data processing system) via the network.

[0096] Referring to Figure 11 , a method M200 for constructing an encrypted communication will be described. The method M200 can be executed by a networked processing system configured to act as a transmission system for a symmetric communication pair. Such a sending system can be, for example, Figure 1 the sending system 110 of Figure 2 the sending system 210 of Figure 4The trading card microprocessor 322. At S210 of method M200, the content of the send system assembly message is sent. This can include a first part consisting of non-sensitive information and a second part consisting of sensitive information. The non-sensitive information can be or include, for example, information that the receiving system can use to identify the sending system and / or other non-sensitive parameters (e.g., a message counter). In some embodiments, the action of assembling the message content can be initiated in response to an authentication request received by the sending system. At S220, the sending system establishes a shared secret value that can be used to generate a message authentication code. In embodiments where the shared secret is statically stored in a memory accessible by the data processor of the sending system, the data processor can establish the shared secret value by retrieving the shared secret value from the memory. In other embodiments, the data processor can retrieve a shared secret master key from the memory and use it in combination with the sending system unique identifier in a shared key generation algorithm to generate a shared key. In some embodiments, the shared key algorithm may also require another shared parameter (e.g., an encrypted message counter) to generate the shared secret value. At S230, the shared secret value can be used by the sending system data processor as a salt in a MAC generation algorithm to generate a message authentication code.

[0097] At S250, the sending data processing system encrypts at least a portion of the message content. In a particular embodiment, the sensitive information portion can be encrypted using a first session key. In some embodiments, the message authentication code can be encrypted together with the sensitive information portion using the first session key. In other embodiments, a second session key can be used to separately encrypt the message authentication code to generate a method authentication ciphertext. As part of the encryption action, the sending system can retrieve a first encryption master key from the memory and combine it with the sending system unique identifier in an encryption key generation algorithm to generate a first sending system unique encryption key (e.g., the first UDK described above with respect to Figure 3 system 300). This in turn can be used to generate a first session key. Similarly, the sending system can retrieve a second encryption master key from the memory and combine it with the sending system unique identifier to generate a second sending system unique encryption key (e.g., the second UDK described above with respect to Figure 3 system 300), and this second sending system key can be used to generate a second session key. In some embodiments, the encryption key generation algorithm may also require another shared parameter (e.g., an encrypted message counter) to generate the shared secret value. In embodiments where an encrypted message counter is used, the counter can be incremented during message encryption or encrypted message transmission.

[0098] At S260, the unencrypted and encrypted portions of the system assembly message are sent and transmitted over the network to the receiving communication system. In some embodiments, the sending system may transmit the assembled message to the receiving communication system via an intermediate communication device, receive the message, and retransmit it over the network to the receiving communication data processing system.

[0099] Referring Figure 12 , a method M300 for authenticating encrypted communication will be described. Method M300 may be performed by a network-enabled processing system configured to act as a receiving system of a symmetric communication pair. Such a receiving system may be, for example, Figure 1 receiving system 120, Figure 2 receiving system 220, or Figure 3 and Figure 8 card message processing system 360 of Figure 2 system 200 and Figure 3 system 300. The receiving system has stored therein or accessible a database containing encryption information of one or more sending data processing systems. The encryption information may include one or more sending system-specific identifiers, one or more encryption master keys, and a shared secret master key. In some embodiments, each master key may be associated with the identifiers of more than one sending system, but may be used together with the sending system-specific identifier to generate a sending system-specific encryption key. In some embodiments (e.g.,

[0100] system 200 and Figure 3 system 300), the encryption information may be received from a third-party data processing system that generates and distributes the master keys.

[0101] At S340, the receiving data processing system decrypts the encrypted portion of the message. In some embodiments, the message includes a sensitive content portion and a message authentication code encrypted together using a first session key. As part of the action at S340, the receiving system may generate or obtain the first session key and use it to decrypt the message authentication code and the sensitive content. In embodiments where the first session key is generated, the receiving system may obtain a first encryption master key from an encryption information database and combine it with the sending system identifier in an appropriate encryption key generation algorithm to generate a first sending-system-unique encryption key (e.g., the first UDK described above with respect to Figure 3 system 300). This, in turn, can be used to generate the first session key.

[0102] In some embodiments, the message authentication code is provided in a separately encrypted ciphertext constructed using a second session key. In these embodiments, the receiving system may obtain a second encryption master key from the encryption information database and combine it with the sending system identifier to generate a second sending-system-unique encryption key (e.g., the second UDK described above with respect to Figure 3 system 300), which can be used to generate the second session key. This can then be used to decrypt the method authentication code.

[0103] In some embodiments, the encryption key generation algorithm may also require another shared parameter (e.g., an encrypted message counter) to generate a shared secret value. In embodiments where an encrypted message counter is used, the counter may be incremented upon receipt of the encrypted message or when decrypting the message.

[0104] At S350, the receiving data processing system obtains a shared secret master key from the encryption information database and uses it together with the sending system identifier to generate a shared secret value using an appropriate shared key generation algorithm. In some embodiments, the shared key generation algorithm may also require one or more additional shared parameters (e.g., an encrypted message counter) to generate the shared key. At S360, the shared key can be used in an appropriate MAC generation algorithm to generate a second message authentication code. At S370, the second message authentication code can be compared with the decrypted password from the message to authenticate the message. A match indicates the authenticity of the message and its source. The receiving system may further process the information in the received message (e.g., initiate or complete a transaction) in response to an affirmative determination of authenticity. However, if the authentication codes do not match, the receiving system may send an error message to the sending system and / or an intermediate device (if any) through which the sending system sent the message. The receiving system may also terminate further processing of the message content and any related transactions. It may also decrement the encrypted message counter (if used).

[0105] The present invention provides an authentication method and system for symmetric encryption communication, wherein a message authentication code can be generated based on a shared key salt value, and the shared secret salt value can be dynamically generated in parallel according to a master key generated by a third-party system. The result is more secure communication and the construction of shared data required for symmetric encryption communication.

[0106] It will be readily understood by those skilled in the art that the present invention has broad utility and applications. Without departing from the essence or scope of the present invention, many embodiments and modifications of the present invention, as well as many variations, modifications, and equivalent arrangements, will be apparent or reasonably implied from the present invention and its foregoing description, in addition to those described herein.

Claims

1. A card, the card comprising: A data processor; A communication interface configured for contact or non-contact communication with an intermediate processing device; And A card memory in which is stored A shared secret master key and a unique card identifier, and A message encryption application, the message encryption application including instructions for the data processor to perform the following steps: Generate a shared secret value using the unique card identifier and the shared secret master key, Generate a message authentication code using the shared secret value, Encrypt at least a portion of the message content using a first session key to generate an encrypted message content, Encrypt the message authentication code, Transmit to the intermediate processing device a message including the encrypted message content and the encrypted message authentication code for retransmission to a receiving communication processing system.

2. The card according to claim 1, Wherein, The message authentication code is encrypted using the first session key.

3. The card according to claim 1, Wherein: The card memory further stores therein at least one encryption master key, and The message encryption application further includes instructions for the data processor to perform the following steps: Generate a first card-unique encryption key using the unique card identifier and the first of the at least one encryption master key, and Generate the first session key using the first card-unique encryption key.

4. The card according to claim 3, Wherein: The message encryption application further includes instructions for the data processor to perform the following steps: Generate a second card-unique encryption key using the unique card identifier and the second of the at least one encryption master key, and Generate a second session key using the second card-unique encryption key, and Encrypt the message authentication code using the second session key.

5. The card according to claim 1, Wherein: The card memory further stores therein an encryption counter, The message encryption application uses the encryption counter together with the unique card identifier and the shared secret master key to generate the shared secret value, and The message encryption application further includes instructions for the data processor to perform the following step: increment the encryption counter after generating the message authentication code.

6. The card according to claim 5, Wherein, The encryption counter is included in the message.

7. A method for facilitating symmetric encryption communication between a transmitting data processing system and a receiving data processing system, the transmitting data processing system having a unique identifier associated therewith, the method Comprising: Generating, by a key generation data processing system, at least one encryption master key, each encryption master key being configured to be used with the unique identifier and a first encryption algorithm to produce a transmission system-unique encryption key; Generating, by the key generation data processing system, a shared secret master key, the shared secret master key being configured to be used with the unique identifier and a second encryption algorithm to generate a shared secret value; The key generation data processing system associates the at least one encrypted master key and the shared secret master key with the unique identifier and stores them in the encrypted information database; The key generation data processing system transmits the at least one encrypted master key and the shared secret information to the transmission data processing system; and The key generation data processing system transmits the at least one encrypted master key, the shared secret master key, and the unique identifier to the receiving data processing system.

8. The method according to claim 7, further comprising: The key generation data processing system generates a shared secret value using the shared secret master key and the second encryption algorithm, wherein the shared secret information is the shared secret value or includes the shared secret value.

9. The method according to claim 7, wherein, the shared secret information is the shared secret master key or includes the shared secret master key.

10. The method according to claim 7, wherein, the transmission data processing system is a microprocessor installed on a transaction card or includes a microprocessor installed on a transaction card, and performs the following actions as part of the configuration process of the transaction card: generating at least one encrypted master key, generating a shared secret master key, storing the at least one cryptographic master key and the shared secret master key, and transmitting the at least one encrypted master key and the shared secret information.

11. The method according to claim 10, wherein, the receiving data processing system is a card message processing system, and the card message processing system is configured to decrypt and authenticate messages transmitted by the transaction card using the at least one encrypted master key and the shared secret master key.

12. The method according to claim 7, wherein, each encrypted master key is configured to use an encryption counter together with the unique identifier and the first encryption algorithm to generate the transmission system unique encryption key.

13. The method according to claim 7, wherein, the shared secret master key is configured to use an encryption counter together with the unique identifier and the second encryption algorithm to generate the shared secret value.

14. A method for authenticating a message transmitted by a sending data processing system, the sending data processing system having a unique identifier associated therewith, wherein the transmitted message includes encrypted content and an encrypted message authentication code, the method comprising: The receiving data processing system receives the transmitted message; The receiving data processing system determines the unique identifier; The receiving data processing system obtains an encrypted information record for the sending data processing system from a database, the encrypted information record including a shared secret master key; The receiving data processing system decrypts the encrypted message authentication code; The receiving data processing system generates a shared secret value using the unique identifier and the shared secret master key; The receiving data processing system generates a comparison message authentication code using the shared secret value; and The comparison message authentication code is compared with the decrypted message authentication code by the receiving data processing system to determine the message authentication result.

15. The method according to claim 14, wherein, the encrypted information record includes at least one encryption master key, and the method further includes: generating, by the receiving data processing system, a first sending system unique encryption key using the unique identifier and the first of the at least one encryption master key; generating a first session key using the first sending system unique encryption key; and decrypting at least a part of the encrypted content using the first session key.

16. The method according to claim 15, wherein, the action of decrypting the encrypted message authentication code is performed using the first session key.

17. The method according to claim 15, further includes: generating, by the receiving data processing system, a second sending system unique encryption key using the unique identifier and the second of the at least one master key; and generating a second session key using the second sending system unique encryption key, wherein the action of decrypting the encrypted message authentication code is performed using the second session key.

18. The method according to claim 14, wherein: the encrypted information record further includes an encryption counter, 19. The method according to claim 18, further includes: incrementing, by the receiving data processing system, the encryption counter in the encrypted information record; and storing the encrypted information record together with the incremented encryption counter in a database.

20. The method according to claim 14, wherein: the unencrypted part of the transmitted message includes an encryption counter, and in addition to using the unique identifier and the shared secret master key, the encryption counter is also used to perform the action of generating a shared secret value.

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