Shannon unicity distance, ε-secrecy criterion and Holevo information in quantum cryptography

Abstract

Abstract In this paper, we consider the relationship between C Shannon’s unicity distance, which is determined by the number of symbols of the encrypted message required to uniquely find the encryption key of the cryptosystem in information-theoretical sense, ε-secrecy criterion in quantum cryptography and Holevo information. A lower bound for the unicity distance for ε-secret keys in quantum cryptography is obtained. The relationship between unicity distance, ε-secrecy criterion in quantum cryptography and Holevo information is demonstrated.