RESILIENT CRYPTOGRAPHIC SCHEME

• US 20100284540A1
• Filed: 07/20/2010
• Published: 11/11/2010
• Est. Priority Date: 01/20/1999
• Status: Active Grant

• Current Assignee: Blackberry Limited
• Original Assignee: Certicom Corporation (Blackberry Limited)
• Inventors: Vanstone, Scott Alexander, Johnson, Donald B.
• Granted Patent: US 8,233,617 B2
• Time in Patent Office: Days
• US Class Current: 380/283
• CPC Class Codes: H04L 9/3242 involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC
• CPC Class Codes: H04L 9/3249 using RSA or related signature schemes, e.g. Rabin scheme

Abstract

A system and method are provided for enabling a symmetric key to be derived, the method comprising: obtaining a plurality of key parts, wherein the plurality of key parts when combined equal the symmetric key; encrypting a first of the key parts using a first cryptographic algorithm to generate a first encrypted value; encrypting one or more remaining key parts of the plurality of key parts using respective cryptographic algorithms to generate one or more additional encrypted values, wherein each key part encrypted is encrypted using a different cryptographic algorithm; and providing the first encrypted value and the one or more additional encrypted values to an other entity to enable the other entity to derive the symmetric key.

Claims

1. A method of enabling a symmetric key to be derived, the method comprising:

obtaining a plurality of key parts, wherein the plurality of key parts when combined equal the symmetric key;

encrypting a first of the key parts using a first cryptographic algorithm to generate a first encrypted value;

encrypting one or more remaining key parts of the plurality of key parts using respective cryptographic algorithms to generate one or more additional encrypted values, wherein each key part encrypted is encrypted using a different cryptographic algorithm; and

providing the first encrypted value and the one or more additional encrypted values to an other entity to enable the other entity to derive the symmetric key.

2. The method according to claim 1, wherein the obtaining comprises obtaining the symmetric key and dividing the symmetric key into the plurality of key parts.

3. The method according to claim 1, wherein applying a symmetric key derivation function to the plurality of key parts derives the symmetric key.

4. The method according to claim 1, wherein the different cryptographic algorithms are chosen from the group comprising:

an elliptic curve (EC) algorithm, a Rivest-Shamir-Adleman (RSA) algorithm, and a discrete logarithm (DL) algorithm.

5. The method according to claim 4, wherein the different cryptographic algorithms correspond to different ones in the group.

6. The method according to claim 1, wherein XORing the plurality of key parts derives the symmetric key.

7. A computer readable medium comprising computer executable instructions that when executed by a computing device, operate the computing device to:

obtain a plurality of key parts, wherein the plurality of key parts when combined equal a symmetric key;

encrypt a first of the key parts using a first cryptographic algorithm to generate a first encrypted value;

encrypt one or more remaining key parts of the plurality of key parts using respective cryptographic algorithms to generate one or more additional encrypted values, wherein each key part encrypted is encrypted using a different cryptographic algorithm; and

provide the first encrypted value and the one or more additional encrypted values to another entity to enable the other entity to derive the symmetric key.

8. A cryptographic unit comprising:

a processor operable to;

obtain a plurality of key parts, wherein the plurality of key parts when combined equal a symmetric key;

encrypt a first of the key parts using a first cryptographic algorithm to generate a first encrypted value;

encrypt one or more remaining key parts of the plurality of key parts using respective cryptographic algorithms to generate one or more additional encrypted values, wherein each key part encrypted is encrypted using a different cryptographic algorithm; and

provide the first encrypted value and the one or more additional encrypted values to another entity to enable the other entity to derive the symmetric key.

9. The cryptographic unit according to claim 8, wherein the plurality of key parts are obtained by obtaining the symmetric key and dividing the symmetric key into the plurality of key parts.

10. The cryptographic unit according to claim 8, wherein applying a symmetric key derivation function to the plurality of key parts derives the symmetric key.

11. The cryptographic unit according to claim 8, wherein the different cryptographic algorithms are chosen from the group comprising:

an elliptic curve (EC) algorithm, a Rivest-Shamir-Adleman (RSA) algorithm, and a discrete logarithm (DL) algorithm.

12. The cryptographic unit according to claim 11, wherein the different cryptographic algorithms correspond to different ones in the group.

13. The cryptographic unit according to claim 8, wherein XORing the plurality of key parts derives the symmetric key.

14. A method of deriving a symmetric key, the method comprising:

obtaining a first encrypted value and one or more additional encrypted values;

decrypting the first encrypted value and the one or more additional encrypted values to obtain a plurality of key parts, wherein each key part decrypted is decrypted from a respective encrypted value using a different cryptographic algorithm; and

combining the plurality of key parts in deriving the symmetric key.

15. The method according to claim 14, wherein the plurality of key parts correspond to respective shared secrets, and wherein applying a symmetric key derivation function to the plurality of key parts derives the symmetric key.

16. The method according to claim 14, wherein the different cryptographic algorithms are chosen from the group comprising:

an elliptic curve (EC) algorithm, a Rivest-Shamir-Adleman (RSA) algorithm, and a discrete logarithm (DL) algorithm.

17. The method according to claim 16, wherein the different cryptographic algorithms correspond to different ones in the group.

18. The method according to claim 14, wherein XORing the plurality of key parts derives the symmetric key.

19. A computer readable medium comprising computer executable instructions that when executed by a computing device, operate the computing device to:

obtain a first encrypted value and one or more additional encrypted values;

decrypt the first encrypted value and the one or more additional encrypted values to obtain a plurality of key parts, wherein each key part decrypted is decrypted from a respective encrypted value using a different cryptographic algorithm; and

combine the plurality of key parts in deriving the symmetric key.

20. A cryptographic unit comprising:

a processor operable to;

obtain a first encrypted value and one or more additional encrypted values;

decrypt the first encrypted value and the one or more additional encrypted values to obtain a plurality of key parts, wherein each key part decrypted is decrypted from a respective encrypted value using a different cryptographic algorithm; and

combine the plurality of key parts in deriving the symmetric key.

21. The cryptographic unit according to claim 20, wherein the plurality of key parts correspond to respective shared secrets, and wherein applying a symmetric key derivation function to the plurality of key parts derives the symmetric key.

22. The cryptographic unit according to claim 20, wherein the different cryptographic algorithms are chosen from the group comprising:

an elliptic curve (EC) algorithm, a Rivest-Shamir-Adleman (RSA) algorithm, and a discrete logarithm (DL) algorithm.

23. The cryptographic unit according to claim 22, wherein the different cryptographic algorithms correspond to different ones in the group.

24. The cryptographic unit according to claim 20, wherein XORing the plurality of key parts derives the symmetric key.