System and method for distributed tokenization using several substitution steps

• US 20110213807A1
• Filed: 03/01/2010
• Published: 09/01/2011
• Est. Priority Date: 03/01/2010
• Status: Active Grant

• Current Assignee: Protegrity USA, Inc. (Xcelera Inc.)
• Original Assignee: Protegrity USA, Inc. (Xcelera Inc.)
• Inventors: Mattsson, Ulf
• Granted Patent: US 8,745,094 B2
• Time in Patent Office: Days
• US Class Current: 707/802
• 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 for distributed tokenization of sensitive strings of characters in a local server, said method comprising the steps:

receiving from a central server at least one static token lookup table;

receiving a sensitive string of characters;

substituting a first substring of characters with a corresponding first token from said at least one token lookup table to form a first tokenized string of characters, said first substring of characters being a substring of said sensitive string of characters; and

substituting a second substring of characters with a corresponding second token from said at least one token lookup table to form a second tokenized string of characters, said second substring of characters being a substring of said first tokenized string of characters.

2. The method of claim 1, wherein said second tokenized string of characters comprises characters which have not been replaced by tokens, said characters thus being identical to the corresponding characters of said sensitive string of characters.

3. The method of claim 1, wherein at least two static token lookup tables are received from said central server, said at least two lookup tables being used to replace different substrings of characters.

4. The method of claim 3, wherein a first of the at least two lookup tables is used to replace the first substring of characters and a second of said at least two lookup tables is used to replace the second substring of characters.

5. The method of claim 1, wherein the second substring includes at least one character having been replaced by said first token.

6. The method of claim 5, wherein the second substring further includes at least one character not having been replaced by said first token.

7. The method of claim 1, further comprising the step of substituting a third substring of characters with a corresponding third token from said at least one token lookup table to form a third tokenized string of characters, said third part of characters being a substring of said second tokenized string of characters

8. The method of claim 1, wherein at least said first substrings of characters comprises only numerical characters, and wherein at least one of said tokens comprises alphanumerical characters.

9. The method of claim 8, wherein at least one substring of characters being replaced by a token comprising alphanumerical characters comprises more characters than the corresponding token.

10. The method of claim 9, further comprising the step of adding additional characters containing metadata to the tokenized string of characters.

11. The method of claim 1, further comprising the steps of:

transferring at least one of said sensitive string of characters and said tokenized string(s) of characters to the central server; and

canceling said sensitive string of characters from said local server within a limited time from said transferring, while maintaining at least one tokenized string of characters in a local database connected to said local server.

12. The method of claim 1, wherein the sensitive string of characters comprises at least one substrings of characters generated in a random fashion, wherein in said step of substituting said part to be replaced is contained within said substring of random characters, the sensitive string of characters preferably comprising at least 16 characters and said substring to be replaced by a token preferably comprising at least 6 characters.

13. The method of claim 1, wherein the at least one token lookup table is a list mapping at least one token value to each possible character combination of the part of said sensitive string of characters to be replaced.

14. The method of claim 1, further comprising the step of at least before one of the steps of substituting a substring of characters with a corresponding token, modifying, in a predetermined way, the substrings to be tokenized.

15. The method of claim 14, wherein the modification of the substring to be tokenized is made with an initialization vector.

16. The method of claim 15, wherein the initialization vector is formed by characters or digits in the sensitive string of characters which are not to be replaced by tokens.

17. A local server for distributed tokenization of sensitive strings of characters comprising:

means for receiving from a central server at least one static token lookup table;

means for receiving a sensitive string of characters;

means for substituting a first substring of characters with a corresponding first token from said at least one token lookup table to form a first tokenized string of characters, said first substring of characters being a substring of said sensitive string of characters; and

means for substituting a second substring of characters with a corresponding second token from said at least one token lookup table to form a second tokenized string of characters, said second substring of characters being a substring of said first tokenized string of characters.

18. A system for distributed tokenization of sensitive strings of characters comprising:

a central server capable of generating static token lookup table; and

at least one local server;

wherein the at least one local server comprises;

means for receiving from the central server at least one static token lookup table;

means for receiving a sensitive string of characters;

means for substituting a first substring of characters with a corresponding first token from said at least one token lookup table to form a first tokenized string of characters, said first substring of characters being a substring of said sensitive string of characters; and

means for substituting a second substring of characters with a corresponding second token from said at least one token lookup table to form a second tokenized string of characters, said second substring of characters being a substring of said first tokenized string of characters.