TW202127339A - Offline card transaction authentication system and offline card transaction authentication method - Google Patents

Abstract

An offline card transaction authentication system and an offline card transaction authentication method are provided. A user card records an asymmetric private key and balance information and generates a symmetric session key. A transaction authentication host includes a card reader coupled to the user card and generates the symmetric session key. In response to that the transaction authentication host receives a transaction instruction, the transaction authentication host and the user card perform a authentication procedure according to the symmetric session key. In response to that the user card passes the authentication procedure, the transaction authentication host and the user card perform a transaction specified by the transaction instruction, and the user card adjusts the balance information according to the transaction. The user card generates a digital signature for a transaction record of the transaction by using the asymmetric private key and stores the digital signature and the transaction record to a storage medium.

Description

Off-line card transaction authentication system and off-line card transaction authentication method

The present invention relates to an electronic transaction technology, and particularly relates to an offline card transaction authentication system and an offline card transaction authentication method.

With the advancement of technology, electronic transaction services using electronic cards have gradually become popular. Furthermore, in today's living environment, for the sake of safety and convenience, many application transaction environments have been changed to various types of electronic cards to replace real money. For example, tickets, counter cards, telephone cards, etc., are all electronic cards. The range that can be used. Users need to spend real money and store equivalent virtual points or virtual money in an electronic card to use the electronic card for consumption, use a specific instrument, or obtain consideration services, etc.

Generally speaking, in the process of a user using an electronic card to conduct a transaction, the key authentication procedure is a common identity verification method and a transaction verification method. In addition, in order to protect and confirm the balance or remaining points in the e-card, the current common practice is to track each transaction record of the e-card through an online cloud database, so that the remaining points can be returned correctly when the e-card is lost or damaged Number or balance. However, regardless of the key authentication process or the use of online cloud databases, most transaction hosts on the debit side need to be connected to the Internet to upload transaction records to the online cloud database or obtain the necessary keys. However, in some specific occasions, based on the consideration of information security or data privacy, it is not expected to use the trading host under the condition of network connection, so as to prevent the intentional person from hacking the trading host to modify or steal through the network. material. On the other hand, many information security vulnerabilities have appeared in the society in recent years, which can easily cause businesses and the public to distrust electronic transactions. It can be seen that the information security issues of electronic transactions such as card tickets cannot be ignored.

In view of this, the present invention proposes an offline card transaction authentication system and an offline card transaction authentication method, which can use electronic cards for transactions in an offline environment, thereby ensuring the security and confidentiality of electronic card transactions.

The embodiment of the present invention provides an offline card transaction authentication system, which includes a user card and a transaction authentication host. The user card records the asymmetric private key and balance information, and generates a symmetric conference key. The transaction authentication host includes a card reader coupled to the user's card and generates a symmetric conference key. In response to the transaction authentication host receiving the transaction instruction, the transaction authentication host and the user card perform an identity authentication procedure based on the symmetric conference key. In response to the user card passing the identity authentication process, the transaction authentication host performs the transaction specified by the transaction instruction with the user card, and the user card adjusts the balance information according to the transaction. The user card uses the asymmetric private key to generate a digital signature on the transaction record, and stores the digital signature and transaction record in a storage medium.

The embodiment of the present invention provides an offline card transaction authentication method, which includes the following steps. In response to the transaction authentication host receiving the transaction instruction, the symmetric conference key is generated by the user card, the symmetric conference key is generated by the transaction authentication host, and the symmetric conference key is generated by the transaction authentication host and the user card Perform the identity authentication process; it reflects that the user card passes the identity authentication process, the transaction authentication host performs the transaction specified by the transaction instruction with the user card, and the user card adjusts the balance information recorded by the user card according to the transaction; and The user card uses the asymmetric private key to generate a digital signature on the transaction record of the transaction, and stores the digital signature and transaction record in a storage medium.

Based on the above, in the embodiment of the present invention, when the user card is used for electronic transactions, the user card and the transaction authentication host can use the symmetric key encryption method to increase the computing speed during identity authentication. Since the user card and the transaction authentication host do not need to query the public key through the network, the transaction authentication system of the embodiment of the present invention can perform identity authentication in an offline environment, thereby ensuring the data confidentiality of the transaction authentication host. In addition, since each transaction record on the user's card is signed by the asymmetric private key, the verified transaction record facilitates the audit and correctness of the transaction record, and can effectively prevent the intentional person from fraudulently defrauding the illegal balance.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

Part of the embodiments of the present invention will be described in detail in conjunction with the accompanying drawings. The reference symbols in the following description will be regarded as the same or similar elements when the same symbol appears in different drawings. These embodiments are only a part of the present invention, and do not disclose all the possible implementation modes of the present invention. More precisely, these embodiments are just examples of methods and systems within the scope of the patent application of the present invention.

Fig. 1 is a schematic diagram of an offline card transaction authentication system according to an embodiment of the present invention. Please refer to FIG. 1, the offline card transaction authentication system 10 includes a transaction authentication host 120 and a user card 110.

The user card 110 is a smart card (Smart Card), and may also be called an IC card (Integrated Circuit Card). The user card 110 embeds a dedicated processing chip 112 in the card for data storage or calculation processing. More specifically, in one embodiment, the user card 110 may include a transmission interface 111 and a processing chip 112. The transmission interface 111 may be a contact transmission interface or a non-contact (inductive) transmission interface, which is not limited in the present invention. The processing chip 112 is an integration of a processing circuit with computing and data storage capabilities and a memory circuit.

The transaction authentication host 120 includes a card reader 121, an instruction receiving unit 122, a storage medium 123, and a processing circuit 124. The card reading device 121 may be a card slot card reader or an inductive card reader, which is not limited in the present invention. The command receiving unit is, for example, an input device such as a keyboard, a mouse, a touch input element, etc., for receiving commands issued by a user. The storage medium 123 is used to store data, instructions, program codes, software components, etc., and it can be, for example, any type of fixed or removable random access memory (random access memory, RAM), read-only memory (read only). -only memory, ROM), flash memory, hard disk or other similar devices, integrated circuits and combinations thereof.

The processing circuit 124 is coupled to the card reader 121, the instruction receiving unit 122 and the storage medium 123 to control the overall operation of the offline card transaction authentication system 10. In this embodiment, the processing circuit 124 is, for example, a central processing unit (CPU), or other programmable general-purpose or special-purpose microprocessors, or digital signal processors (Digital Signal Processors). , DSP), programmable controller, application specific integrated circuit (Application Specific Integrated Circuits, ASIC), programmable logic device (Programmable Logic Device, PLD), or other similar devices or a combination of these devices.

It should be noted that, in one embodiment, the transaction authentication host 120 can be implemented by a computer device (such as a notebook computer or a desktop computer) and an external card reader 121. The external card reader 121 can be connected to a computer device via a USB interface, for example. In another embodiment, the transaction authentication host 120 may be a computer device with a built-in card reader 121. In addition, in one embodiment, the processing circuit 124 may include a central processing unit of a computer device and a processing chip of another smart card. Alternatively, in an embodiment, the processing circuit 124 may only include the central processing unit of the computer device. Or, in an embodiment, the processing circuit 124 may only include a central processing unit of a computer device and other integrated circuits with computing capabilities.

In one embodiment, the card reader 121 can read data in the user card 110 or provide data to the user card 110, so that the processing circuit 124 can communicate with the user card through the card reader 121.

Fig. 2 is a flowchart of a rearview mirror control method according to an embodiment of the present invention. Please refer to FIG. 2, the method of this embodiment is applicable to the offline card transaction authentication system 10 in the above-mentioned embodiment. The following is a description of the offline card transaction authentication system of this embodiment with various components in the offline card transaction authentication system 10 Detailed steps of the method.

In step S201, in response to the transaction authentication host 120 receiving the transaction command CMD, the user card 110 generates the symmetric conference key "session key", and the transaction authentication host 120 generates the symmetric conference key "session key", And the transaction authentication host 120 and the user card 110 perform the identity authentication process according to the symmetrical conference key "session key".

In detail, when the card holder of the user card 110 wants to conduct a transaction, the system operator can issue the transaction command CMD through the command receiving unit 122. For example, the card holder of the user card 110 can purchase items, the right to use professional equipment, the right to use professional software systems, transportation tickets, or other items based on the amount, points, or virtual currency in the user card 110. Specific services and so on. Prior to this, the card holder of the user card 110 needs to spend real money to purchase the amount, points or virtual currency in the user card 110, which converts the real currency into the amount, points or virtual currency in the card The action is called a stored value. Therefore, the balance information recorded by the user card 110 will change with the consumption action and the stored value action of the card holder of the user card 110. When the card holder of the user card 110 wants to conduct a transaction, the user card 110 will be inserted into or close to the card reader 121 of the transaction authentication host 120, and the system operator can issue a transaction command CMD to the transaction authentication host according to the transaction type 120.

In response to the transaction command CMD, the transaction authentication host 120 and the user card 110 will perform identity authentication according to the symmetric key encryption method. In other words, before the two parties conduct the transaction process, the transaction authentication host 120 and the user card 110 must first go through a dialogue to authenticate each other's identities. In one embodiment, the transaction authentication host 120 and the user card 110 need to perform specific steps to generate the same symmetric conference key "session key" respectively, and use the symmetric conference key "session key" for identity authentication. Here, the symmetrical session key "session key" is a one-time symmetrical key used for encryption in the conversation. The transaction authentication host 120 and the user card 110 use the same key to encrypt the plaintext and decrypt the ciphertext. For example, the encryption algorithm of symmetric key encryption may include Data Encryption Standard (DES), Triple Data Encryption Standard (3DES), Advanced Encryption Standard (AES) , Blowfish algorithm, International Data Encryption Algorithm (IDEA), etc. The present invention is not limited to this.

Next, in step S202, it is reflected that the user card 110 passes the identity authentication process, the transaction authentication host 120 and the user card 110 perform the transaction specified by the transaction command CMD, and the user card 110 adjusts the user card according to the transaction 110 recorded balance information. In one embodiment, the transaction instruction CMD includes a deduction transaction instruction or a stored value transaction instruction, and the transaction includes a deduction transaction or a stored value transaction.

It should be noted that, in one embodiment, the transaction authentication host 120 and the user card 110 can generate a message authentication code (Message authentication code, MAC), so that the other party can verify the integrity of the message based on the received message authentication code. In one embodiment, the symmetrical conference key "session key" may include a first conference key used to verify identity and another second conference key used to verify message integrity. After the transaction authentication host 120 and the user card 110 both successfully authenticate the other party as a legal transaction object according to the first conference key and successfully verify the integrity of the received and sent messages according to the second conference key, the transaction authentication host 120 and the user card 110 can carry out the transaction specified by the transaction command CMD. For example, the user card 110 can deduct the amount or points required for the transaction from the balance information, and the transaction authentication host 120 can unlock the use right of a specific instrument or professional software according to the transaction content. In this way, the holder of the user card 110 can use specific equipment or professional software through payment.

In one embodiment, the user card 110 records a first encryption key K1, and the user card 110 generates a symmetrical conference key "session key" according to the first encryption key K1. The transaction authentication host 120 has a second encryption key K2, and the transaction authentication host 120 derives the first encryption key K1 according to the key derivation function (KDF) and the second encryption key K2. The transaction authentication host 120 then generates a symmetrical conference key "session key" according to the first encryption key K1.

Finally, in step S203, the user card 110 uses the asymmetric private key to generate a digital signature on the transaction record of the transaction, and save the digital signature and transaction record to a storage medium. For example, the digital signature and transaction records can be stored in the storage medium 123 built in the transaction authentication host 120, or the digital signature and transaction records can also be stored in the processing chip 112 of the user card 110. Specifically, when manufacturing the user card 110, the card maker can first generate an asymmetric public key and an asymmetric private key according to the asymmetric encryption algorithm, and write the asymmetric private key to the user And store the asymmetric public key in a database. The aforementioned asymmetric encryption algorithm is, for example, RSA (Rivest-Shamir-Adleman) algorithm, digital signature algorithm (Digital Signature Algorithm, DSA), or elliptic curve digital signature algorithm (Elliptic Curve Digital Signature Algorithm, ECDSA), etc. . Thereby, when the transaction record of the user card 110 is to be audited, the verifier can obtain the asymmetric public key from the database and verify the digital signature and transaction record recorded in the storage medium. The verified digital signature and transaction record can allow the verifier to correctly know the transaction record of the user card 110. In this way, the embodiment of the present invention can provide a card transaction method with verifiable transaction records in an offline environment. In the case that the interested person cannot know the asymmetric private key of the user card 110, the transaction record cannot be forged.

Based on the foregoing knowledge, transactions may include deduction transactions or stored value transactions. However, whether it is a deduction transaction or a stored-value transaction, the identity verification process between the user card 110 and the transaction verification host 120 is similar, and the identity verification and confirmation messages are performed through symmetric key encryption in an offline environment. The correctness. Examples will be listed below to illustrate.

Fig. 3 is a schematic diagram of an offline card transaction authentication system using a SAM card according to an embodiment of the present invention. 3, in this embodiment, when the transaction is a deduction transaction, the transaction authentication host 120 further includes a Secure Access Module (SAM) card 124_1 coupled to the card reader 121. In contrast, the second encryption key K2 used to generate the symmetric conference key includes a deduction encryption key recorded in the SAM card 124_1. The SAM card 124_1 is also a smart card with computing and storage chips. That is, the processing circuit 124 shown in FIG. 1 can be implemented by the processor 124_1 and the SAM card 124_1. In other words, in the embodiment of FIG. 3, the SAM card 124_1 is required for transaction authentication. By writing the second key K2 and the first key K1 derived from the second key K2 into the SAM card 124_1 and the user card 110, respectively, the card maker will manufacture the SAM card 124_1 and the user that can match each other Card 110.

Fig. 4 is a flowchart of a deduction process performed by an offline card transaction authentication system according to an embodiment of the present invention. Please refer to FIG. 4, the method of this embodiment is applicable to the offline card transaction authentication system 10 in the embodiment of FIG. The detailed steps of the authentication method.

It should be noted that, in the following embodiments, the balance information in the user card 110 is described in units of points, but the present invention is not limited to this. That is, the user card 110 needs to spend a certain amount of money to purchase the card points in the user card 110. In step S401, the processor 124_1 of the transaction authentication host 120 receives the transaction command CMD', and the transaction command CMD' is a deduction command. In step S402, the processor 124_1 sends a deduction request to the SAM card 124_1 in response to the transaction command CMD'. In step S403, the SAM card 124_1 generates a first random number. In step S404, the SAM card 124_1 sends the first random number to the processor 124_1 of the transaction authentication host 120. In step S405, the processor 124_1 of the transaction authentication host 120 sends the first random number and deduction information to the user card 110, and the deduction information may include deduction transaction points and a time stamp.

Next, in step S406, the user card 110 generates a second random number in response to receiving the deduction point information. The user card 110 records the first encryption key for deduction. In step S407, the user card 110 generates a symmetric conference key according to the first encryption key, the transaction counter, the first random number, and the second random number, and encrypts the first random number and the second random number according to the symmetric conference key. The concatenated sequence of random numbers generates the first encrypted token. In step S408, the user card 110 sends the user card number, the user card unique identification code (UUID), the second random number, the deduction information, the balance information, and the first encrypted token to the SAM card 124_1. In addition, in step S408, the user card 110 can also generate a MAC based on the above-mentioned signal content and send it to the SAM card 124_1.

The SAM card 124_1 records the debit encryption key. In step S409, the SAM card 124_1 derives the first encryption key according to the key derivation function (KDF) and the deduction encryption key, and according to the first encryption key, the transaction counter, the first random number, and the second random number Generate a symmetric conference key. In step S410, the SAM card 124_1 uses the symmetric conference key to verify the first encryption token. The SAM card 124_1 uses the symmetric conference key to decrypt the first encrypted token, thereby verifying by comparing the random number information in the decryption result with the first random number. In addition, the SAM card 124_1 can verify the integrity of the message according to the MAC from the user card 110. In step S411, the SAM card 124_1 generates a second encrypted token by encrypting the concatenation sequence of the second random number and the first random number according to the symmetric conference key. In step S413, the SAM card 124_1 sends the user card number, deduction point information, balance information, and the second encrypted token to the user card 110.

In step S414, the user card 110 confirms the transaction information and uses the symmetric conference key to verify the second encryption token. The user card 110 uses the symmetric conference key to decrypt the second encrypted token, thereby verifying by comparing the random number information in the decryption result with the second random number. In step S415, the user card 110 adjusts the balance information according to the deduction information, that is, deducts the deduction transaction points in the deduction information from the balance. For example, if the balance information is originally 50 points and the point deduction transaction points are 5 points, the balance information of the user card 110 will be reduced to 45 points based on the deduction point information of the deduction transaction. In step S416, the user card 110 uses the asymmetric private key to generate a digital signature on the transaction record, that is, uses the asymmetric private key to sign the transaction record. In step S417, the user card 110 sends the transaction record and the digital signature to the processor 124_1 and records it in the storage medium 123. The transaction record includes the user card number, deduction point information, and balance information.

Based on the process shown in FIG. 4, the user card 110 can perform an identity authentication process with the transaction authentication host 120 in an offline environment to perform a deduction transaction, and send the transaction record with a digital signature to the transaction authentication host 120 for later Audit.

Specifically, in one embodiment, the transaction record includes the user card number of the user card 110. The verification host can access all transaction records and digital signatures of multiple user cards in the storage medium 123. The verification host may be the transaction verification host 120 or other devices, and the present invention is not limited thereto. The verification host can search the database for an asymmetric public key matching the asymmetric private key of the user card 110 according to the card number of the user card 110, and verify the digital signature according to the asymmetric public key. To audit the transaction records of the user card 110.

Based on the description of FIGS. 3 to 4, in one embodiment, the keys in the SAM card and the user card can be sorted into the following example table 1. Table 1 Card name Record key name Key type Derivative source use User card Private key EC_C EC 256 Digital signature The first encryption key dDEDIT_C for deduction AES 128 dDEDIT_SC Authentication MAC key for deduction dDEDIT_MAC_C AES 128 dDEDIT_MAC_SC Message complete verification SAM card Debit encryption key dDEDIT_SC AES 128 kDEBIT Authentication MAC key for deduction dDEDIT_MAC_SC AES 128 kDEBIT_MAC Authentication Among them, kDEBIT and kDEBIT_mac are the top-level keys possessed by the card maker. That is, the symmetric encryption keys recorded on the SAM card and the user card are all derived from the top key of the card maker.

Fig. 5 is a schematic diagram of an offline card transaction authentication system using a dealer card according to an embodiment of the present invention. 5, in this embodiment, when the transaction is a stored-value transaction, the transaction authentication host 120 further includes a dealer card 124_3 coupled to the card reader 121. In contrast, the second encryption key K2 used to generate the symmetric conference key includes a stored-value encryption key recorded in the dealer card 124_3. The dealer card 124_3 is also a smart card with computing and storage chips, and the dealer card 124_3 records the number of dealership points available for users to purchase. That is, the processing circuit 124 shown in FIG. 1 can be implemented by the processor 124_1 and the dealer card 124_3. In other words, in the embodiment of FIG. 5, the dealer card 124_3 is required to perform the transaction authentication and stored value process. By writing the second key K2 and the first key K1 derived from the second key K2 into the dealer card 124_3 and the user card 110, respectively, the card maker will make a dealer card 124_3 that can be matched with each other and use it者卡110。 The card 110.

Fig. 6 is a flow chart of the process of storing value in an offline card transaction authentication system according to an embodiment of the present invention. Please refer to FIG. 6, the method of this embodiment is applicable to the offline card transaction authentication system 10 in the embodiment of FIG. The detailed steps of the authentication method.

It should be noted that the identity authentication process between the dealer card 124_3 and the user card 110 is similar to the identity authentication process between the SAM card 124_1 and the user card 110 in the foregoing embodiment. In step S601, the processor 124_1 of the transaction authentication host 120 receives the transaction command CMD’’, and the transaction command CMD’’ is a stored value command. In step S602, the processor 124_1 sends a stored value request to the dealer card 124_3 in response to the transaction command CMD'. In step S603, the dealer card 124_3 generates a first random number. In step S604, the dealer card 124_3 sends the first random number to the processor 124_1 of the transaction authentication host 120. In step S605, the processor 124_1 of the transaction authentication host 120 sends the first random number and stored value information to the user card 110, and the stored value information may include stored value transaction points and a time stamp.

Next, in step S606, the user card 110 generates a second random number in response to receiving the stored value information. The user card 110 records a first encryption key for storing value. In step S407, the user card 110 generates a symmetric conference key according to the first encryption key, the transaction counter, the first random number, and the second random number, and encrypts the first random number and the second random number according to the symmetric conference key. The concatenated sequence of random numbers generates the first encrypted token. In step S608, the user card 110 sends the user card number, the user card UUID, the second random number, the stored value information, the balance information, and the first encrypted token to the dealer card 124_3. In addition, in step S408, the user card 110 can also generate a MAC based on the above-mentioned signal content and send it to the dealer card 124_3.

The dealer card 124_3 records the stored value encryption key. In step S609, the SAM card 124_1 derives the first encryption key according to the key derivation function (KDF) and the stored value encryption key, and according to the first encryption key, the transaction counter, the first random number, and the second random number Generate a symmetric conference key. In step S610, the dealer card 124_3 uses the symmetric conference key to verify the first encryption token. In addition, the dealer card 124_3 verifies the integrity of the message according to the MAC from the user card 110. In step S611, the dealer card 124_3 generates a second encrypted token by encrypting the concatenation sequence of the second random number and the first random number according to the symmetric conference key. In step S613, the dealer card 124_3 sends the user card number, stored value information, balance information, and the second encrypted token to the user card 110. In addition, after the dealer card 124_3 verifies the identity of the user card 110, in step S612, the dealer card 124_3 can adjust the dealer balance information in the dealer card 124_3 according to the stored value information. For example, the dealership balance in the dealer card 124_3 available for the user card 110 to support purchasers was originally 1000 points. If the stored value transaction points in the stored value information are 100 points, then the dealership in the dealer card 124_3 The balance will be reduced to 900 points.

In step S614, the user card 110 confirms the transaction information and uses the symmetric conference key to verify the second encryption token. In step S615, the user card 110 increases the balance information according to the stored value information, that is, adds the balance to the stored value transaction points in the stored value information. In step S616, the user card 110 uses the asymmetric private key to generate a digital signature on the transaction record, that is, uses the asymmetric private key to sign the transaction record. In step S617, the user card 110 sends the transaction record and the digital signature to the processor 124_1 and records it in the storage medium 123. The transaction record includes the user card number, stored value information, and balance information.

Based on the process shown in FIG. 6, the user card 110 can perform an identity authentication process with the transaction authentication host 120 in an offline environment to perform a stored-value transaction, and send the transaction record with a digital signature to the transaction authentication host 120 for later Audit. Similarly, the verification host can also verify the transaction record of the stored value of the user card 110.

Based on the description of FIG. 5 to FIG. 6, in one embodiment, the keys in the user card and the dealer card can be sorted into the following example table 2. Table 2 Card name Record key name Key type Derivative source use User card Private key EC_C EC 256 Digital signature The first encryption key for storing value dCREDIT_C AES 128 dDREDIT_P Authentication MAC key for recharge dCREDIT_MAC_C AES 128 dDREDIT_MAC_P Message complete verification Dealer Card Stored value encryption key dDEDIT_P AES 128 kDEBIT Authentication MAC key for recharge dDEDIT_MAC_P AES 128 kDEBIT_MAC Message complete verification Among them, kDEBIT and kDEBIT_MAC are the top-level keys possessed by the card maker. That is, the symmetric encryption keys recorded on the dealer card and the user card are all derived from the top key of the card maker.

In summary, in the embodiment of the present invention, the symmetric key encryption method is used when the card and the transaction authentication host perform identity verification, and the digital signature of the transaction record is generated according to the asymmetric key encryption method. Thereby, the embodiment of the present invention can avoid the steps of asymmetric key management book and transaction authentication host inquiring the public key online during identity authentication, so that fast and low-cost identity verification can be performed in an offline environment. In this way, it is possible to prevent the transaction authentication host from being exposed to the network connection environment and its stored data from being stolen or tampered with. In addition, since the embodiment of the present invention generates the digital signature of the transaction record based on the asymmetric key encryption method, the offline card transaction authentication system can record the verifiable transaction record in the offline environment for the verification host to use the public The key is used to verify the correctness of the transaction record for audit.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be subject to those defined by the attached patent application scope.

10: Offline card transaction authentication system 110: User Card 120: Transaction authentication host 111: Transmission interface 112: Handling wafers 121: card reader 122: instruction receiving unit 123: storage medium 124: Processing circuit 124_1: processor 124_2: SAM card 124_3: Dealer Card CMD, CMD’, CMD’’: trading instructions S201～S203, S401～S417, S601～S617: steps

Fig. 1 is a schematic diagram of an offline card transaction authentication system according to an embodiment of the present invention. Fig. 2 is a flowchart of an offline card transaction authentication method according to an embodiment of the present invention. Fig. 3 is a schematic diagram of an offline card transaction authentication system using a SAM card according to an embodiment of the present invention. Fig. 4 is a flowchart of a deduction process performed by an offline card transaction authentication system according to an embodiment of the present invention. Fig. 5 is a schematic diagram of an offline card transaction authentication system using a dealer card according to an embodiment of the present invention. Fig. 6 is a flow chart of the process of storing value in an offline card transaction authentication system according to an embodiment of the present invention.

S201~S203: steps

Claims (14)

An offline card transaction authentication system, the system includes: A user card records an asymmetric private key and balance information, and generates a symmetric conference key; A transaction authentication host includes a card reader coupled to the user card and generates the symmetric conference key, The response is that the transaction authentication host receives a transaction instruction, and the transaction authentication host and the user card perform an identity authentication procedure based on the symmetric conference key. In response to the user card passing the identity authentication process, the transaction authentication host performs a transaction specified by the transaction instruction with the user card, and the user card adjusts the balance information according to the transaction, The user card uses the asymmetric private key to generate a digital signature for the transaction record of the transaction, and stores the digital signature and transaction record in a storage medium. For example, in the offline card transaction authentication system described in item 1 of the scope of patent application, the transaction instruction includes a deduction transaction instruction or a stored value transaction instruction, and the transaction includes a deduction transaction or a stored value transaction. For example, the offline card transaction authentication system described in item 2 of the scope of patent application, wherein the user card records a first encryption key, the user card generates the symmetric conference key according to the first encryption key, and The transaction authentication host has a second encryption key, the transaction authentication host derives the first encryption key according to a key derivation function (KDF) and the second encryption key, and the transaction authentication host derives the first encryption key according to the first encryption The key generates the symmetric conference key. The offline card transaction authentication system described in item 3 of the scope of patent application, wherein the transaction authentication host further includes a secure access module card coupled to the card reader, and the second encryption key includes records recorded in the Securely access the debit encryption key in the card of the module. The offline card transaction authentication system described in item 3 of the scope of patent application, wherein the transaction authentication host further includes a dealer card coupled to the card reader, and the second encryption key includes records recorded on the dealer card The stored value encryption key in. In the offline card transaction authentication system described in item 1 of the scope of patent application, the storage medium is built in the transaction authentication host. For example, the offline card transaction authentication system described in item 1 of the scope of patent application, wherein the transaction record includes a card number of the user card, The offline card transaction authentication system further includes a verification host. The verification host searches for an asymmetric public key from a database based on the card number, and verifies the digital signature based on the asymmetric public key to Audit the transaction record of the user card. An offline card transaction authentication method, including: In response to a transaction authentication host receiving a transaction instruction, a symmetric conference key is generated by the user card, the symmetric conference key is generated by the transaction authentication host, and the transaction authentication host and the user The user card performs an identity authentication procedure based on the symmetric conference key; It reflects that the user card passes the identity authentication process, the transaction authentication host performs a transaction specified by the transaction instruction with the user card, and the user card adjusts the recorded value of the user card according to the transaction. Balance information; and The user card uses the asymmetric private key to generate a digital signature for the transaction record of the transaction, and stores the digital signature and transaction record in a storage medium. For example, in the offline card transaction authentication method described in item 8 of the scope of patent application, the transaction instruction includes a deduction transaction instruction or a stored value transaction instruction, and the transaction includes a deduction transaction or a stored value transaction. For example, in the off-line card transaction authentication method described in claim 9, wherein the user card records a first encryption key, the user card generates the symmetric conference key according to the first encryption key, and The transaction authentication host has a second encryption key, the transaction authentication host derives the first encryption key according to a key derivation function (KDF) and the second encryption key, and the transaction authentication host derives the first encryption key according to the first encryption The key generates the symmetric conference key. According to the off-line card transaction authentication method described in claim 10, the transaction authentication host further includes a secure access module card coupled to the card reader, and the second encryption key is recorded in the secure Access the debit encryption key in the module card. The offline card transaction authentication method according to item 10 of the scope of patent application, wherein the transaction authentication host further includes a dealer card coupled to the card reader, and the second encryption key is included in the dealer card The stored value encryption key in. In the offline card transaction authentication method described in item 8 of the scope of patent application, the storage medium is built in the transaction authentication host. The offline card transaction authentication method described in item 8 of the scope of patent application, wherein the transaction record includes a card number of the user card, and the method further includes: A verification host searches for an asymmetric public key from a database based on the card number, and verifies the digital signature based on the asymmetric public key to audit the transaction record of the user card.

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