Encryption using alternate authentication key

• US 8,713,311 B1
• Filed: 11/07/2012
• Issued: 04/29/2014
• Est. Priority Date: 11/07/2012
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Roskind, James
• Primary Examiner(s): ABYANEH, ALI S
• Application Number:
  US13/671,508
• Time in Patent Office: 538 Days
• Field of Search: 713/161, 713/171, 726/2, 726/5, 380/255, 380/277
• US Class Current: 713/161
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/123 received data contents, e.g. message integrity

Abstract

Methods for changing authentication keys when transmitting data are provided. In one aspect, a method includes receiving a first data packet including a first sender-generated authentication value generated using a first authentication key, and a first message encrypted using a first encryption key, and receiving an indication that subsequent packets will include authentication values generated using a second authentication key. The method also includes receiving a second packet includes a second sender-generated authentication value and an encrypted second message, and applying the second authentication key to the second packet to generate a recipient-generated authentication value. The encrypted second message is decrypted if these two authentication values match. Otherwise, the first authentication key is applied to the second packet to generate another recipient-generated authentication value. If these two authentication values match, the encrypted message is decrypted using the first encryption key. Systems and machine-readable media are also provided.

Claims

1. A computer-implemented method for changing authentication keys when transmitting data, the method comprising:

receiving a first data packet comprising a first sender-generated authentication value generated using a first authentication key, and a first message encrypted using a first encryption key;

receiving an indication that subsequent data packets will include authentication values generated using a second authentication key;

receiving a second data packet comprising a second sender-generated authentication value and an encrypted second message;

applying the second authentication key to the second data packet to generate a recipient-generated authentication value;

when the recipient-generated authentication value that is generated using the second authentication key matches the second sender-generated authentication value, decrypting the encrypted second message; and

when the recipient-generated authentication value that is generated using the second authentication key does not match the second sender-generated authentication value;

applying the first authentication key to the second data packet to generate another recipient-generated authentication value; and

when the recipient-generated authentication value that is generated using the first authentication key matches the second sender-generated authentication value, decrypting the encrypted message using the first encryption key,

wherein the first authentication key and the second authentication key comprise Message Authentication Code (MAC) keys, and

wherein the first authentication key and the first encryption key are included in a first cipher specification.

2. The computer-implemented method of claim 1, wherein the indication that subsequent data packets will include authentication values generated using the second authentication key is received over an encrypted channel.

3. The computer-implemented method of claim 1, wherein the method further comprises transmitting an acknowledgement that the indication that subsequent data packets will include authentication values generated using the second authentication key has been received prior to applying the second authentication key to the second data packet to generate the recipient-generated authentication value.

4. The computer-implemented method of claim 1, wherein the first authentication key comprises a public authentication key and the second authentication key comprises a private authentication key.

5. The computer-implemented method of claim 1, wherein the first cipher specification comprises an Authenticated Encryption with Associated Data (AEAD) block cipher mode.

6. The computer-implemented method of claim 1, wherein receiving the indication that subsequent data packets will include authentication values generated using the second authentication key comprises receiving an indication that subsequent data packets will be generated according to a second cipher specification comprising the second authentication key and a second encryption key, and wherein decrypting the encrypted second message comprises decrypting the encrypted second message using the second encryption key.

7. The computer-implemented method of claim 1, wherein receiving the indication that subsequent data packets will include authentication values generated using the second authentication key comprises receiving a cipher specification notification.

8. The computer-implemented method of claim 1, wherein the first data packet comprises a first packet number, and the second data packet comprises a second packet number that succeeds the first packet number.

9. The computer-implemented method of claim 8, wherein when the recipient-generated authentication value that is generated using the second authentication key matches the second sender-generated authentication value, applying the second authentication key to each data packet comprising a packet number successive to the first packet number.

10. A system for changing authentication keys when transmitting data, the system comprising:

a memory comprising instructions; and

a processor configured to execute the instructions to;

receive a first data packet comprising a first sender-generated authentication value generated using a first authentication key, and a first message encrypted using a first encryption key;

receive a cipher specification notification indicating that subsequent data packets will include authentication values generated using a second authentication key;

receive a second data packet comprising a second sender-generated authentication value and an encrypted second message;

apply the second authentication key to the second data packet to generate a recipient-generated authentication value;

when the recipient-generated authentication value that is generated using the second authentication key matches the second sender-generated authentication value, decrypt the encrypted second message; and

when the recipient-generated authentication value that is generated using the second authentication key does not match the second sender-generated authentication value;

apply the first authentication key to the second data packet to generate another recipient-generated authentication value; and

when the recipient-generated authentication value that is generated using the first authentication key matches the second sender-generated authentication value, decrypt the encrypted message using the first encryption key,

wherein the first authentication key and the second authentication key comprise Message Authentication Code (MAC) keys, and

wherein the first authentication key and the first encryption key are included in a first cipher specification.

11. The system of claim 10, wherein the indication that subsequent data packets will include authentication values generated using the second authentication key is received over an encrypted channel.

12. The system of claim 10, wherein the processor is further configured to transmit an acknowledgement that the indication that subsequent data packets will include authentication values generated using the second authentication key has been received prior to applying the second authentication key to the second data packet to generate the recipient-generated authentication value.

13. The system of claim 10, wherein the first authentication key comprises a public authentication key and the second authentication key comprises a private authentication key.

14. The system of claim 10, wherein the first cipher specification comprises an Authenticated Encryption with Associated Data (AEAD) block cipher mode.

15. The system of claim 10, wherein the processor being configured to receive the indication that subsequent data packets will include authentication values generated using the second authentication key comprises the processor being configured to receive an indication that subsequent data packets will be generated according to a second cipher specification comprising the second authentication key and a second encryption key, and wherein the processor being configured to decrypt the encrypted second message comprises the processor being configured to decrypt the encrypted second message using the second encryption key.

16. The system of claim 10, wherein the first data packet comprises a first packet number, and the second data packet comprises a second packet number that succeeds the first packet number.

17. The system of claim 16, wherein when the recipient-generated authentication value that is generated using the second authentication key matches the second sender-generated authentication value, applying the second authentication key to each data packet comprising a packet number successive to the first packet number.

18. A non-transitory machine-readable storage medium comprising machine-readable instructions for causing a processor to execute a method for changing authentication keys when transmitting data, the method comprising:

receiving a first data packet comprising a first sender-generated authentication value generated using a first Message Authentication Code (MAC) authentication key, and a first message encrypted using a first encryption key;

receiving a cipher specification notification message over an encrypted channel that subsequent data packets will be generated according to a second cipher specification comprising a second MAC authentication key and a second encryption key;

transmitting an acknowledgement that the second cipher specification notification has been received;

receiving a second data packet comprising a second sender-generated authentication value and an encrypted second message;

applying the second authentication key to the second data packet to generate a recipient-generated authentication value;

when the recipient-generated authentication value that is generated using the second authentication key matches the second sender-generated authentication value, decrypting the encrypted second message using the second MAC encryption key; and

when the recipient-generated authentication value that is generated using the second authentication key does not match the second sender-generated authentication value;

applying the first authentication key to the second data packet to generate another recipient-generated authentication value; and

when the recipient-generated authentication value that is generated using the first authentication key matches the second sender-generated authentication value, decrypting the encrypted message using the first encryption key,

wherein the first MAC authentication key and the first encryption key are included in a first cipher specification.