Practical Approaches to Attaining Security against Adaptively Chosen Ciphertext Attacks

摘要: This paper presents three methods for strengthening public key cryptosystems in such a way that they become secure against adaptively chosen ciphertext attacks. In an attack, attacker can query the deciphering algorithm with any ciphertexts, except exact object to be cryptanalyzed. The first method is based on use of one-way hash functions, second universal functions and third digital signature schemes. Each illustrated by example cryptosystem intractability computing discrete logarithms finite fields. Two other issues, namely applications intractable problems enhancement information authentication capability cryptosystems, are also discussed.