Secure two-party comparing protocol based on evaluation of encrypted functions
Liang Chen, Yong Xu · Jisuanji yingyong yanjiu · 2010
Secure two-party comparing is a special case and a basic module of secure computations,and is applied in mobile code and e-commerce security etc.But known solutions have some disadvantages:expensive costs of computing and communicating,limited ranges of compared numbers.Based on a modified ElGamal algorithm,this paper presented and proved multiplicative,mixed-multiplicative,additive and subtractive homomorphic cryptosystem.Constructed an encrypted function unknown by two-party using the homomorphic cryptosystem.Based on the homomorphic cryptosystem and evaluation of encrypted functions,designed secure two-party comparing protocol under semi-honest model.Proof,example and comparing with other protocols show the proposed protocol has the merits of security,fairness,lower costs of communication and computational complexity,and comparing integers.