Patent ID: 9641333
Date: 2017-05-02
CPC Classifications: G06F,H04L

Claim:
1. A method of authenticating a client computing device to a server, the method including the steps of: (i) the authentication approach using a pairing based cryptographic approach, using type-3 pairing defined by a mapping e: G1×G2→GT, in which G1, G2 and GT are all cyclic groups of the same prime order q and in which the groups G1 and G2 are distinct, and in which Q is a fixed point in G2, the client computing device receiving an encrypted identifier (s-ε)A from a trusted authority, the trusted authority having used its master key s and a secret ε to encrypt the encrypted identifier (s-ε)A associated with the client computing device, where A=H1(ID), where H1 is a hash function which hashes its input to a point on G1, and ID is an identifier of the client computing device; (ii) the server receiving from the trusted authority a secret sQ encrypted by the trusted authority using the master key s; (iii) the client computing device generating a random x<q, and calculating A=H1(ID) and U=xA; (iv) the client computing device calculating y=H(U|T), where H is a hash function which hashes its input to an element in Fq, and T is a time stamp; (v) the client computing device calculating V=−(x+y)(s-ε)A; (vi) the client computing device sending ID, U, T and V to the server in an authentication request; (vii) the server rejecting the authentication request if T is not current, the server otherwise proceeding to step (viii); (viii) the server calculating A=H1(ID) and y=H(U|T); (ix) the server calculating g=e(V,Q)·e(U+yA,sQ)=e(U,Q)^(ε), and solving for ε; (x) the server recording that the client computing device with the identifier ID has supplied the secret ε in an encrypted form, and (xi) the server authenticating the client computer.