Lifetime of Authentication Using Encrypted Tags When the Encryption Key is Partially Known
(English)Manuscript (preprint) (Other academic)
Quantum cryptography is an unconditionally secure key growing technique provided that an unconditionally secure authentication protocol is combined with it. This paper is about the study of the lifetime of a message authentication scheme, where a message to be authenticated is first hashed by a secret–but fixed–Strongly Universal hash function then the output is encrypted with a one-time-pad key to generate a tag for the message. If the onetime-pad is completely secret, then the lifetime is exponential in the tag length. If, however, the one-time-pad key is partially known in each authentication round, as is the case in practical quantum key distribution protocols, then the picture is different; because the adversary’s partial knowledge of the one-time-pad key in each authentication round contributes to his/her ability to identify the secret hash function. We estimate the lifetime of this type of authentication. Here the parameters are the length of the key identifying the secret hash function and the amount of knowledge that Eve has on the one-time-pad. A theoretical estimate is presented, along with experimental results that support it.
Quantum cryptography, quantum key distribution, authentication, strongly universal hash functions, lifetime
IdentifiersURN: urn:nbn:se:liu:diva-57289OAI: oai:DiVA.org:liu-57289DiVA: diva2:324698