SECURING COMMUNICATIONS SENT BY A FIRST USER TO A SECOND USER

• US 20100235627A1
• Filed: 03/11/2010
• Published: 09/16/2010
• Est. Priority Date: 03/13/2009
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Kerschbaum, Florian, Sorniotti, Alessandro
• Granted Patent: US 8,688,973 B2
• Time in Patent Office: Days
• US Class Current: 713/156
• CPC Class Codes: G06F 21/445 by mutual authentication, e.g. between devices or programs
• CPC Class Codes: H04L 9/002 Countermeasures against attacks on cryptographic mechanisms network architectures or network communication protocols for protection against malicious traffic H04L63/1441
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04L 9/3073 involving pairings, e.g. identity based encryption [IBE], bilinear mappings or bilinear pairings, e.g. Weil or Tate pairing
• CPC Class Codes: H04L 9/321 involving a third party or a trusted authority
• CPC Class Codes: H04L 9/3271 using challenge-response

Abstract

A computer-implemented method of securing communications sent by a first user to a second user may include receiving, by a first user from a trusted third party, at least one public cryptographic value corresponding to the first user and at least one private cryptographic value corresponding to the first user, providing, by the first user to a second user, a plurality of values corresponding to an identification device identified by an identifier, deriving, by the first user, a shared key, using the at least one private cryptographic value of the first user, and at least one of the plurality of values corresponding to the identification device identified by the identifier and protecting communications sent by the first user to the second user with the shared key.

Claims

1. A computer-implemented method of securing communications sent by a first user to a second user, the method comprising:

receiving, by a first user from a trusted third party, at least one public cryptographic value corresponding to the first user and at least one private cryptographic value corresponding to the first user;

providing, by the first user to a second user, a plurality of values corresponding to an identification device identified by an identifier;

deriving, by the first user, a shared key, using the at least one private cryptographic value of the first user, and at least one of the plurality of values corresponding to the identification device identified by the identifier; and

protecting communications sent by the first user to the second user with the shared key.

2. The computer-implemented method of claim 1 wherein providing the plurality of values comprises providing a first value which is a function of a cryptographic identifier of the identification device.

3. The computer-implemented method of claim 2 wherein providing the plurality of values comprises providing a second value which is a function of at least one private cryptographic value of the second user.

4. The computer-implemented method of claim 3 wherein providing the plurality of values comprises storing, by the first user, the plurality of values on the identification device identified by the identifier.

5. The computer-implemented method of claim 4 wherein storing the plurality of values comprises updating the stored plurality of values by replacing at least one value of the stored plurality of values with a re-encrypted value.

6. The computer-implemented method of claim 4 further comprising:

receiving, by the first user from the trusted third party, a value which is a function of a secret cryptographic value of the second user;

computing a value which is a function of a private cryptographic value of the second user using the value that is a function of the secret cryptographic value of the second user;

updating the stored plurality of values by replacing the second value of the stored plurality of values with the computed value; and

storing the updated plurality of values on the identification device identified by the identifier.

7. The computer-implemented method of claim 5 wherein updating the stored plurality of values comprises:

sending, by the first user, the second value of the stored plurality of values to the trusted third party; and

receiving, by the first user from the trusted third party, the re-encrypted value, where the re-encrypted value is derived from the second value of the stored plurality of values.

8. The computer-implemented method of claim 1 wherein providing the plurality of values comprises providing a first value which is a function of the at least one private cryptographic value of the second user.

9. The computer-implemented method of claim 1 further comprising performing mutual authentication to verify that the first user and the second user have accessed the identification device identified by the identifier.

10. The computer-implemented method of claim 9 wherein deriving the shared key comprises performing mutual authentication, and wherein performing mutual authentication comprises:

sending, by the first user to the second user, a random challenge; and

receiving, by the first user from the second user, a value which is a function of the random challenge and at least one private cryptographic value of the second user.

11. The computer-implemented method of claim 9 further comprising comparing, by the first user, a function of the second value of the stored plurality of values with a function of at least one public cryptographic value of the second user.

12. The computer-implemented method of claim 9 wherein performing mutual authentication comprises comparing the shared key derived by the first user with the shared key of the second user.

13. The computer-implemented method of claim 11 wherein the comparing operation is performed by providing values as inputs to an efficiently computable, non-degenerate, bilinear map for which the Computational Diffie-Hellman Problem cannot be computed efficiently.

14. A computer system for providing secure communications among a plurality of users, the system comprising:

an identification device, wherein the identification device is identified by an identifier and the identification device comprises a memory;

a first computing device that is arranged and configured to process instructions to store a plurality of values on the identification device identified by the identifier;

a second computing device; and

a third computing device that is arranged and configured to;

provide at least one public cryptographic value to the first computing device and the second computing device, and

provide at least one private cryptographic value to the first computing device and the second computing device;

wherein the first computing device is operable to derive a shared key from the at least one private cryptographic value provided to the first computing device and at least one of the plurality of values stored on the identification device identified by the identifier, and

wherein the second computing device is operable to derive the shared key from the at least one private cryptographic value provided to the second computing device and at least one of another plurality of values stored on the identification device identified by the identifier.

15. The computer system of claim 14 wherein the identification device comprises a Radio Frequency Identification (RFID) tag.

16. A recordable storage medium having recorded and stored thereon instructions that, when executed, perform the actions of:

receiving, by a first user from a trusted third party, at least one public cryptographic value corresponding to the first user and at least one private cryptographic value corresponding to the first user;

providing, by the first user to a second user, a plurality of values corresponding to an identification device identified by an identifier;

deriving, by the first user, a shared key, using the at least one private cryptographic value of the first user, and at least one of the plurality of values corresponding to the identification device identified by the identifier; and

protecting communications sent by the first user to the second user with the shared key.

17. The recordable storage medium of claim 16 wherein instructions that, when executed, perform the action of providing the plurality of values comprise instructions that, when executed, perform the action of providing a first value which is a function of a cryptographic identifier of the identification device.

18. The recordable storage medium of claim 17 wherein instructions that, when executed, perform the action of providing the plurality of values comprise instructions that, when executed, perform the action of providing a second value which is a function of at least one private cryptographic value of the second user.

19. The recordable storage medium of claim 18 wherein instructions that, when executed, perform the action of providing the plurality of values comprise instructions that, when executed, perform the action of storing, by the first user, the plurality of values on the identification device identified by the identifier.

20. The recordable storage medium of claim 19 further comprising instructions that, when executed, perform the actions of:

receiving, by the first user from the trusted third party, a value which is a function of a secret cryptographic value of the second user;

computing a value which is a function of a private cryptographic value of the second user using the value that is a function of the secret cryptographic value of the second user;

updating the stored plurality of values by replacing the second value of the stored plurality of values with the computed value; and

storing the updated plurality of values on the identification device identified by the identifier.