Secure multiparty computation (SMC) has become research focus in the international cryptographic community in recent years.Privately determining equality of data is a basic problem in SMC.It is widely applied to fingerprint matching

keyword searching and so on.Studying privately determining equality of data has important theoretical and practical significance.Protocol I which is based on the Paillier cryptosystem can privately determine equality of two rational numbers.Protocol Ⅱ which is based on elliptic curve cryptosytem can privately determine equality of multiple rational numbers.Finally this paper gives the protocol for privately determining equality of rational numbers in the malicious model.