On The Efficiency Of Public Key Cryptosystem

Security problem and efficiency problem are among the most important factors of public-key cryptosystem. The security of public key cryptosystem is based on an NP problem,such as the discrete logarithm problem. While the working speed depends on the design of the scheme. In this thesis, we give an analysis of a knapsack cryptosystem. We also analyze the efficiency of an elliptic curve digital signature Scheme. Finally we provide an improved elliptic curve digital signature scheme, which avoids the possibility of invalid signature and improves the working speed of the elliptic curve digital signature scheme.