STUDY OF THE AUTHENTICATION IN THE UNCONDITIONALLY SECURE SECRET KEY AGREEMENT
Liu Sheng · Chinese Journal of Computers · 1999
An unconditionally secure secret key agreement protocol usually consists of three phases, Initialization phase, communication phase and decision phase. For a scenario where two communicants and an adversary 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. This paper illustrates with an example that when the adversary's channel is noisier than the communicants' channels during the initialization phase, a ( N,K,d ) linear code can always be found to implement the authentication scheme, ensuring that the receiver accepts the sender's legitimate messages with probability at least 1-1/s 2 while rejects Eve's fraudulent messages with probability at least 1- 1/s ′ 2, where s and s′ are secure parameters. At last, this paper shows that the lower bound of the required authenticator length is closely related to the secure parameters s,s′ , code rate of the authentication scheme K/(K+N) and bit error probabilities of independent noise channels in the initialization phase.