AN AUTHENTICATED ENCRYPTION SCHEME WITH （t,n） SHARED VERIFICATION AND ITS SECURITY

An authenticated encryption scheme with （t, n） shared verification is a method allowing n verifiers to share the responsibility for message recovery in such a way that any t or more of them can cooperatively reconstruct the message, while any t-1 or less of them can not. In 1998, Hsu and Wu proposed an authenticated encryption scheme with （t, n） shared verification,which can not resist the cheating attack. An improvement of the Hsu-Wu’s scheme is presented, the security of which is based on the factoring and discrete logarithm problem. This improved scheme against multiform cheating achieves higher security level and requires fewer transmitted messages than the existing scheme.