Patent ID: 7747865

Claim:
A method of exchange between two parties interconnected by a device or network, said method comprising: a recipient party (verifier) computer choosing a secret value x for computing a value X=F1(x), where F1 comprises a first predetermined function having at least one argument, said value x being one of said at least one argument of F1; a signing party (signer) computer choosing a secret value y for computing a value Y=F2(y), where F2 comprises a second predetermined function having at least one argument, said value y being one of said at least one argument of F2; said signer obtaining said value X, said signer having a private key b and a public key B; and said signer computing a value s=F3(y,b,X), where F3 comprises a third predetermined function having at least three arguments, said value y, said private key b, and said value X being three arguments of said at least three arguments of F3, wherein a fourth predetermined function F4(x,Y,B) exists to calculate a value s′, F4 having at least three arguments, said value x, said value Y, and said public key B being three arguments of said at least three arguments of F4 but a value s not being an argument of F4, there exists no secret shared between said verifier and said signer that serves as a basis for any argument in any of said F1, F2, F3, and F4, and said verifier considers said values s and s′ as valid authenticators when value s′ is determined to be related in a predetermined manner to value s, wherein: said public key B=g b , g being a generator of a finite group of order q, said private key b being an integer such that 0≦b≦q−1; said value x=g x , x being an integer such that 0≦x≦q−1, and said value Y=g y , y being an integer such that 0≦y≦q−1; and said signer calculates said value s=f 1 (X) f 2 (m,Y,y,b) , f 1 comprises a first mathematical function, and f 2 comprises a second mathematical function, and argument m comprises a message, q is prime, f 1 consists of an identity function, f 2 comprises a hash function such that said at least one argument of f 2 is hashed, said message m comprises an identity of a party in a computer or system or network, f 2 (m,Y,y,b)=y+H(Y,m)b mod q, where H comprises a cryptographic function being one of a one-way function, an encryption function, and a cryptographic hash function, and x is chosen by said verifier at random and y is chosen by said signer at random.