Transmission system

• US 6,766,451 B1
• Filed: 01/27/2000
• Issued: 07/20/2004
• Est. Priority Date: 01/28/1999
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Van Rijnsoever, Bartholomeus J.
• Primary Examiner(s): Peeso, Thomas R.
• Application Number:
  US09/491,651
• Time in Patent Office: 1,636 Days
• Field of Search: 713/160, 713/194, 713/200, 713/201
• US Class Current: 713/160
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/164 at the network layer
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/12 Transmitting and receiving encryption devices synchronised or initially set up in a particular manner

Abstract

The transmission system according to the invention comprises a transmitter (10) and a receiver (14). The transmitter can transmit data packets, e.g. IP packets, to the receiver. These data packets comprise a header (24), e.g. an ESP header, and an encrypted data field (26). The data fields (26) can be decrypted in the receiver (14) by means of a changing decryption key (48). The header (24) comprises information (32) indicating a change of the decryption key (48). This information (32) may be included in the SPI field of an ESP header. In this way the receiver (14) can determine exactly when to start using a new decryption key (48).

Claims

1. A transmission system for transmitting data packets from a transmitter to a receiver, said data packets comprising a header and an encrypted data field, said data fields being decryptable by means of a changing decryption key, wherein the header comprises a synchronization bit that toggles so as to indicate exactly when a change of the decryption key is to be used by the receiver.

2. A transmission system according to claim 1, wherein the data packets comprise IP packets.

3. A transmission system according to claim 2, wherein the header comprises an ESP header, said ESP header comprising the information indicating a change of the decryption key.

4. A transmission system according to claim 3, wherein the ESP header comprises a SPI field, said SPI field comprising the synchronization bit that indicates when a change of the decryption key has occurred.

5. A transmitter for transmitting data packets to a receiver, said data packets comprising a header and an encrypted data field, said data fields being decryptable by means of a changing decryption key, wherein the header comprises a synchronization bit that toggles so as to indicate exactly when a change of the decryption key occurs.

6. A transmitter according to claim 5, wherein the data packets comprise IP packets.

7. A transmitter according to claim 6, wherein the header comprises an ESP header, said ESP header comprising the synchronization bit that indicates a change of the decryption key has occurred.

8. A transmitter according to claim 7, wherein the ESP header comprises a SPI field, said SPI field comprising the synchronization bit that toggles so as to indicate exactly when a change of the decryption key has occurred.

9. A receiver for receiving data packets from a transmitter, said data packets comprising a header and an encrypted data field, said data fields being decryptable by means of a changing decryption key, said receiver being embodied so as to decrypt the encrypted data fields, wherein the header includes a synchronization bit that indicates exactly when a change of the decryption key is to be used by the receiver.

10. A receiver according to claim 9, wherein the data packets comprise IP packets.

11. A receiver according to claim 10, wherein the header comprises an ESP header, said ESP header comprising the synchronization bit that indicates a change of the decryption key.

12. A receiver according to claim 11, wherein the ESP header comprises a SPI field, said SPI field comprising the synchronization bit that indicates a change of the decryption key.

13. A method for transmitting data packets from a transmitter to a receiver, said data packets comprising a header and an encrypted data field, said data fields being decryptable by means of a changing decryption key, wherein the method comprises the indication of a change of the decryption key in the header.

14. A method according to claim 13, wherein the data packets comprise IP packets.

15. A method according to claim 14, wherein the header comprises an ESP header, said indication of a change of the decryption key being comprised in the ESP header.

16. A method according to claim 15, wherein the ESP header comprises a SPI field, said indication of a change of the decryption key being comprised in the SPI field.

17. A compound signal comprising data packets, said data packets comprising a header and an encrypted data field, said data fields being decryptable by means of a changing decryption key, wherein the header comprises a synchronization bit that indicates a change of the decryption key.

18. A compound signal according to claim 17, wherein the data packets comprise IP packets.

19. A compound signal according to claim 18, wherein the header comprises an ESP header, said ESP header comprising the synchronization bit that indicates a change of the decryption key.

20. A compound signal (12) according to claim 19, wherein the ESP header comprises a SPI field, said SPI field comprising the synchronization bit that indicates a change of the decryption key.