Modiied Maurer-yacobi's Scheme and Its Applications

In Eurocrypt'91, Maurer and Yacobi developed a method for building a trapdoor into the one-way function of exponentiation modulo a composite number which enables an identity-based non-interactive key distribution system. In this paper, we provide some improvements of their scheme and then present a modiied trapdoor one-way function by combining Maurer-Yacobi's scheme and RSA scheme. We demonstrate that a lot of applications can be constructed based on this modiied scheme which are impossible in the original scheme. As examples, we present several protocols based on it, such as identiications, key distributions and signature schemes. We have implemented the Pohlig-Hellman and Pollard's-methods for computing discrete logarithms modulo a composite number , which shows that average running time for computing logarithms is too large to be realizable in practice. Therefore, considering current algorithms and technology, we maintain that it is more eecient and practical to take a certiicate-based scheme on which all protocols presented in this paper can be based as well.