Method and device for transmitting information with verification of unintentional and intentional transmission errors
View Patent ↗For the transmission of information with verification of transmission errors, a useful information message (M) is transmitted in a determined frame while being associated with a determined number p of transmission error verification bits (CRC,S) also transmitted in the frame. In order to have an element allowing the verification of intentional errors, determined number p1 of the transmission error verification bits form a seal (S) obtained from a determined sealing function, where p1 is a number less than p. Application to radiocommunications equipment requiring the verification of the integrity and the authentication of the messages transmitted.
1. A method of transmitting information with verification of transmission errors, comprising the steps of:
transmitting, through a radio sender, in a determined frame a useful information message associated with a determined number p of transmission error verification bits also transmitted in said determined frame,
obtaining a seal from the useful information message using a determined sealing function through a seal calculation module, the seal forming a determined number p1 of said p transmission error verification bits where p1 is a number less than p, and
calculating a cyclic redundancy code from the useful information message formed using the p−p1 remaining transmission error verification bits through a channel coder.
2. The method according to claim 1 wherein the p1 transmission error verification bits are calculated at the Medium Access Control (MAC) protocol layer, and are then delivered to a channel coder at the physical layer.
3. The method according to claim 1 , wherein the seal is obtained by truncating to p1 the result of the sealing function which is obtained on a number of bits greater than p1.
4. The method according to claim 3 , wherein the sealing function is of Hash Message Authentication Code or Hash-MAC type with key, with a Hash function selected from the group comprising a Message-Digest Algorithm 5 (MD5) function, a Secure Hash Algorithm 1 (SHA-1) function, a Secure Hash Algorithm 256 (SHA-256) function and sealing functions designed on the basis of a block encryption algorithm.
5. The method according to claim 1 , wherein the results of the sealing function is obtained directly on p1 bits.
6. The method according to claim 5 , wherein the sealing function comprises a combination of a pseudorandom generation function and of a non-linear coding function.
7. A device for transmitting information with verification of transmission errors, comprising:
means for transmitting in a determined frame a useful information message associated with a determined number p of transmission error verification bits also transmitted in said determined frame, and
means for obtaining a seal from the useful information message using a determined sealing function, which seal forms a determined number p1 of said p transmission error verification bits, where p1 is a number less than p, the p−p1 remaining bits forming a cyclic redundancy code calculated from the useful information message.
8. The device according to claim 7 , comprising means for calculating the p1 transmission error verification bits at the MAC Medium Access Control (MAC) protocol layer, as well as a channel coder to which said p1 bits are delivered at the physical layer.
9. The device according to claim 7 , comprising means for obtaining the seal by truncating to p1 the result of the sealing function which is obtained on a number of bits greater than p1.
10. The device according to claim 9 , wherein the sealing function is of Hash-MAC type with key, with a Hash function selected from the group comprising a MD5 function, a SHA-1 function, a SHA-256 function and sealing functions designed on the basis of a block encryption algorithm.
11. The device according to claim 7 , comprising means for obtaining the result of the sealing function directly on p1 bits.
12. The device according to claim 11 , wherein the sealing function comprises a combination of a pseudorandom generation function and of a non-linear coding function.
13. Radiocommunications equipment comprising a device according to claim 7 .