| 摘要 |
<p>The invention concerns a method and a system for authenticating with symmetrical algorithm essentially characterised in that, for each mutual authentication of two parties, a cryptographic computation with a variable key, referred to as K', is carried out. The main steps of said method are as follows: a) party A, possessing the secret key K, sends a random number R2 to party B, the latter also possessing the same secret key K; b) party B selects a random number R2, and computes the number K', which is also a secret key, from the following formula: K' = R2 xor K, xor being the equivalent of the exclusive or mathematical operation; c) then, B, using a symmetrical encryption algorithm ALG, computes a result r derived from the formula: r = ALG[K'](R1); d) said party B then sends r and R2 to said party A; e) said party A, using the same symmetrical encryption algorithm ALG, computes K' and r' from the following formulae: K' = R2 xor K and r' = ALG[k'](R1); f) if r is equal to r', then said party B is authenticated by said party A.</p> |
