Secret-key Agreement with Channel State Information at the Transmitter

We study the capacity of secret-key agreement over a wiretap channel with state parameters. The transmitter communicates to the legitimate receiver and the eavesdropper over a discrete memoryless wiretap channel with a memoryless state sequence. The transmitter and the legitimate receiver generate a common key that must be concealed from the eavesdropper. We assume that the state sequence is known non-causally to the transmitter and no public discussion channel is available. We derive lower and upper bounds on the secret-key capacity. The lower bound involves constructing a common reconstruction sequence at the legitimate terminals and binning the set of reconstruction sequences to obtain the secret-key. For the special case of Gaussian channels with additive interference (secret-keys from dirty paper channel) our bounds differ by 0.5 bit/symbol and coincide in the high signal-to-noise-ratio and high interferenceto-noise-ratio regimes. For the case when the legitimate receiver is also ...

• Type: Journal
• Year: 2010
• Where: CORR
• Authors: Ashish Khisti, Suhas N. Diggavi, Gregory W. Wornell
• Keywords: CORR 2010, Education, Legitimate Receiver, State Sequence, Transmitter