Limited-use keys and cryptograms

• US 11,164,176 B2
• Filed: 12/19/2014
• Issued: 11/02/2021
• Est. Priority Date: 12/19/2013
• Status: Active Grant

• Current Assignee: Visa International Service Association (Visa, Inc.)
• Original Assignee: Visa International Service Association (Visa, Inc.)
• Inventors: Ngo, Hao, Aabye, Christian, Sheets, John, Makhotin, Oleg
• Primary Examiner(s): Qayyum, Zeshan
• Application Number:
  US14/577,678
• Publication Number:
  US 20150178724A1
• Time in Patent Office: 2,510 Days
• Field of Search: 705 71
• CPC Class Codes: G06Q 20/322 Aspects of commerce using mobile devices [M-devices]
• CPC Class Codes: G06Q 20/326 Payment applications installed on the mobile devices
• CPC Class Codes: G06Q 20/327 Short range or proximity payments by means of M-devices
• CPC Class Codes: G06Q 20/3672 initialising or reloading thereof
• CPC Class Codes: G06Q 20/3829 involving key management
• CPC Class Codes: G06Q 20/385 using an alias or single-use codes
• CPC Class Codes: G06Q 20/389 Keeping log of transactions for guaranteeing non-repudiation of a transaction
• CPC Class Codes: G06Q 2220/00 Business processing using cryptography postage metering system using cryptography G06Q2250/05
• CPC Class Codes: H04L 2209/24 Key scheduling, i.e. generating round keys or sub-keys for block encryption
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 9/0869 involving random numbers or seeds

Abstract

Techniques for enhancing the security of a communication device when conducting a transaction using the communication device may include encrypting account information with a first encryption key to generate a second encryption key, and encrypting key index information using the second key to generate a limited-use key (LUK). The key index information may include a key index having information pertaining to generation of the LUK. The LUK and the key index can be provided to the communication device to facilitate generation of a transaction cryptogram for a transaction conducted using the communication device, and the transaction can be authorized based on the transaction cryptogram generated from the LUK.

Claims

1. A method for enhancing security of a communication device when conducting a transaction using the communication device, the method comprising:

encrypting, by a computer system, account information with a first encryption key to generate a second encryption key;

encrypting, by the computer system, key index information using the second encryption key to generate a limited-use key (LUK), wherein the key index information includes a key index having a counter value indicating a number of times that the LUK has been renewed in a predetermined time period, and time information indicating when the LUK is generated, and wherein the LUK is associated with a set of one or more limited-use thresholds that limits usage of the LUK; and

providing, by the computer system, the LUK and the key index to the communication device via an application platform computer;

receiving, by the computer system, the key index information and a transaction cryptogram generated by the communication device, the transaction cryptogram including transaction data encrypted by the LUK;

verifying, by the computer system, that the transaction cryptogram was encrypted using the LUK, and that the LUK has not exceeded the one or more limited-use thresholds, wherein verifying that the transaction cryptogram was encrypted using the LUK includes;

regenerating the transaction cryptogram using the received key index information; and

based on the verifying, authorizing the transaction.

2. The method of claim 1, wherein verifying that the transaction cryptogram was encrypted using the LUK includes:

comparing a result of the regenerating to the received transaction cryptogram.

3. The method of claim 1, wherein the transaction is conducted without using a secure element.

4. The method of claim 1, wherein the set of one or more limited-use thresholds limits the number of transactions that can be conducted using the LUK.

5. The method of claim 1, wherein the account information includes a token that is a substitute for an account identifier.

6. The method of claim 1, wherein the first encryption key is a master derivation key associated with an issuer of an account associated with the account information.

7. The method of claim 6, wherein the second encryption key is a unique derivation key for the account.

8. The method of claim 1, wherein encrypting the account information with the first encryption key to generate the second encryption key includes:

encrypting the account information using the first encryption key to generate a first portion of the second encryption key;

inverting the account information; and

encrypting the inverted account information using the first encryption key to generate a second portion of the second encryption key.

9. The method of claim 1, wherein encrypting the key index information using the second encryption key to generate the LUK includes:

padding the key index with a first value to generate a first padded key index information;

encrypting the first padded key index information to generate a first portion of the LUK;

padding the key index with a second value to generate a second padded key index information; and

encrypting the second padded key index information to generate a second portion of the LUK.

10. The method of claim 1, wherein the transaction cryptogram is generated by:

enciphering transaction information using a first portion of the LUK;

deciphering the enciphered transaction information using a second portion of the LUK; and

re-enciphering the deciphered transaction information using the first portion of the LUK.

11. The method of claim 1, wherein the transaction cryptogram is generated by:

encrypting a predetermined numeric string using the LUK; and

decimalizing the encrypted predetermined numeric string.

12. The method of claim 11, wherein decimalizing the encrypted predetermined numeric string includes:

extracting numeric digits from the encrypted predetermined numeric string to form a first data block;

extracting hexadecimal digits from the encrypted predetermined numeric string and converting each extracted hexadecimal digit into a numeric digit to form a second data block; and

concatenating the first data block and the second data block.

13. A computer system for enhancing security of a communication device when conducting transactions using the communication device, the computer system comprising:

one or more processors; and

one or more memories storing computer-readable code, which when executed by the one or more processors, causes the computer system to perform operations including;

encrypting account information with a first encryption key to generate a second encryption key;

encrypting key index information using the second encryption key to generate a limited-use key (LUK), wherein the key index information includes a key index having a counter value indicating a number of times that the LUK has been renewed in a predetermined time period, and time information indicating when the LUK is generated, and wherein the LUK is associated with a set of one or more limited-use thresholds that limits usage of the LUK;

providing the LUK and the key index to the communication device via an application platform computer;

receiving the key index information and a transaction cryptogram generated by the communication device, wherein the transaction cryptogram includes transaction data encrypted by the LUK;

verifying that the transaction cryptogram was encrypted using the LUK, and that the LUK has not exceeded the one or more limited-use thresholds, wherein verifying that the transaction cryptogram was encrypted using the LUK includes;

regenerating the transaction cryptogram using the received key index information; and

based on the verifying, authorizing the transaction.

14. The computer system of claim 13, wherein verifying that the transaction cryptogram was encrypted using the LUK includes:

comparing a result of the regenerating to the received transaction cryptogram.

15. The computer system of claim 13, wherein the transaction is conducted without using a secure element.

16. The computer system of claim 13, wherein the set of one or more limited-use thresholds limits the number of transactions that can be conducted using the LUK.

17. The computer system of claim 13, wherein the account information includes a token that is a substitute for an account identifier.

18. The computer system of claim 13, wherein the first encryption key is a master derivation key associated with an issuer of an account associated with the account information.

19. The computer system of claim 18, wherein the second encryption key is a unique derivation key for the account.

20. The computer system of claim 13, wherein encrypting the account information with the first encryption key to generate the second encryption key includes:

encrypting the account information using the first encryption key to generate a first portion of the second encryption key;

inverting the account information; and

encrypting the inverted account information using the first encryption key to generate a second portion of the second encryption key.

21. The computer system of claim 13, wherein encrypting the key index information using the second encryption key to generate the LUK includes:

padding the key index with a first value to generate a first padded key index information;

encrypting the first padded key index information to generate a first portion of the LUK;

padding the key index with a second value to generate a second padded key index information; and

encrypting the second padded key index information to generate a second portion of the LUK.

22. The computer system of claim 13, wherein the transaction cryptogram is generated by:

enciphering transaction information using a first portion of the LUK;

deciphering the enciphered transaction information using a second portion of the LUK; and

re-enciphering the deciphered transaction information using the first portion of the LUK.

23. The computer system of claim 13, wherein the transaction cryptogram is generated by:

encrypting a predetermined numeric string using the LUK; and

decimalizing the encrypted predetermined numeric string.

24. The computer system of claim 23, wherein decimalizing the encrypted predetermined numeric string includes:

extracting numeric digits from the encrypted predetermined numeric string to form a first data block;

extracting hexadecimal digits from the encrypted predetermined numeric string and converting each extracted hexadecimal digit into a numeric digit to form a second data block; and

concatenating the first data block and the second data block.