| 摘要 |
PROBLEM TO BE SOLVED: To provide a cryptographic method at a high security level that blocks an attack of inferring a secret key by differential fault analysis.SOLUTION: The method for securely exchanging messages M between at least two devices D1, D2 each storing a shared secret key K comprises the steps of: at each device, generating a random number R1, R2, then sending it to the other device; determining a first key K1 by a first operation on the basis of the secret key and each random number; determining a second key K2 on the basis of the first key and the random numbers; at a sending device D1, determining a pseudo message M' on the basis of the message M and the random numbers; calculating and sending a cryptogram C on the basis of the pseudo message M' and the second key K2; at the receiving device D2, decrypting the cryptogram C by means of the second key; and then retrieving the message M from the pseudo message M'. |
