Distributed tokenization using several substitution steps

• US 9,639,716 B2
• Filed: 11/16/2015
• Issued: 05/02/2017
• Est. Priority Date: 03/01/2010
• Status: Active Grant

• Current Assignee: Protegrity US Holding LLC
• Original Assignee: Protegrity USA, Inc. (Xcelera Inc.)
• Inventors: Mattsson, Ulf
• Primary Examiner(s): Dang, Thanh-Ha
• Application Number:
  US14/942,668
• Publication Number:
  US 20160070927A1
• Time in Patent Office: 533 Days
• Field of Search: 707802
• CPC Class Codes: G06F 16/90344 by using string matching techniques
• CPC Class Codes: G06F 21/6245 Protecting personal data, e.g. for financial or medical purposes
• CPC Class Codes: G07F 7/084 Additional components relating to data transfer and storing, e.g. error detection, self-diagnosis
• CPC Class Codes: G07F 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB

Abstract

A method for distributed tokenization of sensitive strings of characters, such as social security numbers, credit card numbers and the like, in a local server is disclosed. The method comprises the steps of receiving from a central server at least one, and preferably at least two, static token lookup tables, and receiving a sensitive string of characters. In a first tokenization step, a first substring of characters is substituted with a corresponding first token from the token lookup table(s) to form a first tokenized string of characters, wherein the first substring of characters is a substring of the sensitive string of characters. Thereafter, in a second step of tokenization, a second substring of characters is substituted with a corresponding second token from the token lookup table(s) to form a second tokenized string of characters, wherein the second substring of characters is a substring of the first tokenized string of characters. Optionally, one or more additional tokenization steps is/are used.

Claims

1. A method of tokenization, comprising:

accessing a string of characters;

accessing a first token table and a second token table, each of the first token table and the second token table mapping each of a set of input values to a different token value, the first token table different than the second token table;

replacing, by a processor, a first substring of the string of characters with a first token value mapped to a value of the first sub string of characters by the first token table to form a first intermediate string of characters;

replacing a second substring of the intermediate string of characters with a second token value mapped to a value of the second sub string of characters by the second token table to form a second intermediate string of characters; and

combining the second intermediate string of characters with metadata describing the tokenization to form a tokenized string of characters.

2. The method of claim 1, further comprising one or more of:

modifying the first substring before replacing the first substring with the first token value, wherein the first token value comprises a token value mapped to a value of the modified first sub string by the first token table, and modifying the second substring before replacing the second substring with the second token value, wherein the second token value comprises a token value mapped to a value of the modified second substring by the second token table.

3. The method of claim 2, wherein one or more of the first sub string or the second substring is modified based at least in part on an initialization vector.

4. The method of claim 1, wherein the second substring comprises fewer characters than the first substring.

5. The method of claim 1, wherein the second substring comprises at least one character not replaced by the first token.

6. The method of claim 1, wherein accessing the first token table and the second token table comprises selecting the first token table and the second token table from a set of token tables.

7. The method of claim 1, wherein the set of input values comprises every possible value of a given input value length.

8. The method of claim 1, wherein the first substring of the string of characters comprises one of:

the entire string of characters, and less than all of the string of characters.

9. The method of claim 1, wherein the second substring of the intermediate string of characters comprises one of:

the entire intermediate string of characters, and less than all of the intermediate string of characters.

10. The method of claim 1, wherein a length of the combined second intermediate string of characters and metadata is equal a length of the intermediate string of characters.

11. A system comprising:

a processor and a non-transitory computer-readable medium storing executable computer instructions configured to, when executed by the processor, cause the system to perform steps comprising;

accessing a string of characters;

accessing a first token table and a second token table, each of the first token table and the second token table mapping each of a set of input values to a different token value, the first token table different than the second token table;

replacing a first substring of the string of characters with a first token value mapped to a value of the first substring of characters by the first token table to form a first intermediate string of characters;

replacing a second substring of the intermediate string of characters with a second token value mapped to a value of the second sub string of characters by the second token table to form a second intermediate string of characters; and

combining the second intermediate string of characters with metadata describing the tokenization to form a tokenized string of characters.

12. The system of claim 11, the instructions further configured to perform steps comprising one or more of:

modifying the first substring before replacing the first substring with the first token value, wherein the first token value comprises a token value mapped to a value of the modified first substring by the first token table, and modifying the second substring before replacing the second substring with the second token value, wherein the second token value comprises a token value mapped to a value of the modified second substring by the second token table.

13. The system of claim 12, wherein one or more of the first substring or the second substring is modified based at least in part on an initialization vector.

14. The system of claim 11, wherein the second substring comprises fewer characters than the first substring.

15. The system of claim 11, wherein the second substring comprises at least one character not replaced by the first token.

16. A non-transitory computer-readable storage medium storing executable computer instructions that, when executed by a hardware processor, perform steps comprising:

accessing a string of characters;

accessing a first token table and a second token table, each of the first token table and the second token table mapping each of a set of input values to a different token value, the first token table different than the second token table;

replacing a first substring of the string of characters with a first token value mapped to a value of the first substring of characters by the first token table to form a first intermediate string of characters;

replacing a second substring of the intermediate string of characters with a second token value mapped to a value of the second sub string of characters by the second token table to form a second intermediate string of characters; and

combining the second intermediate string of characters with metadata describing the tokenization to form a tokenized string of characters.

17. The non-transitory computer-readable storage medium of claim 16, wherein the instructions, when executed, perform one or more further steps comprising:

modifying the first substring before replacing the first substring with the first token value, wherein the first token value comprises a token value mapped to a value of the modified first sub string by the first token table, and modifying the second substring before replacing the second substring with the second token value, wherein the second token value comprises a token value mapped to a value of the modified second substring by the second token table.

18. The non-transitory computer-readable storage medium of claim 17, wherein one or more of the first substring or the second substring is modified based at least in part on an initialization vector.

19. The non-transitory computer-readable storage medium of claim 16, wherein the second substring comprises fewer characters than the first substring.

20. The non-transitory computer-readable storage medium of claim 16, wherein the second substring comprises at least one character not replaced by the first token.