- PROVABLY SECURE PUBLIC KEY ENCRYPTION SCHEME BASED ON COMPUTATIONAL DIFFIE-HELLMAN ASSUMPTION

摘要

PURPOSE: An encryption method using a public key based on a computational Diffie-Hellman assumption is provided to offer a secure coding on an ACCA(Adaptive Chosen Ciphertext Attack) and shorter coding statement than a conventional one based on a computational Diffie-Hellman assumption, not a deterministic Diffie-Hellman assumption. CONSTITUTION: An encryption method using a public key based on a computational Diffie-Hellman assumption comprises steps of selecting variables p, q and g as public key parameters in a decoder where p is a large prime number with a length of k, and q is also a prime number which can divide p-1(500), selecting and opening a first hash function assuring a security on the ACCA and a second hash function assuring a security under the computational Diffie-Hellman assumption(510), selecting x as a private key based on the public key parameters p, q and g, generating a public key corresponding to the private key x, and opening the public key parameters and public key p, q, g, and X(520), generating coding statements by using the public key X(530), checking an effectivity on the transmitted coding statements(540), and decoding the coded statements by using the private key x(550).