It is necessary to authenticate the messages over an insecure and non-authentic public channel in information-theoretic secret-key agreement. For a scenario where all three parties receive the output of a binary symmetric source over independent binary symmetric channels as their initial information, an authentication scheme is proposed based on coding theory, which uses the correlated strings between the two communicants to authenticate the messages over the public channel. How to select coding parameters to meet the safety requirements of the authentication scheme is described. This paper also illustrates with an example that when the adversary's channel is noisier than the communicants' channels during the initialization phase, such an authentication scheme always exists, and the lower bound of the length of authenticators is closely related to the safety parameters, code rate of the authentication scheme and bit error probabilities of independent noise channels in the initialization phase.
展开▼
