Space-time transmissions for wireless secret-key agreement with information-theoretic secrecy

An important building block of the cross-layer network security design is the physical-layer security which addresses problems such as whether the physical-layer can have build-in security and whether physical-layer techniques can assist the upper-layer encryption-based security techniques. This paper provides a positive answer by realizing information-theoretic secrecy with space-time transmissions. While most existing results on information-theoretic secrecy rely on some impractical assumptions, we propose a more practical approach that uses the redundancy of space-time transmissions to create intentional ambiguity to the adversary. Secrecy can be guaranteed even if the adversary has extremely high receiving signal-to-noise ratio. This approach is presented as a new way for secret-key agreement. Simulations in terms of receiving error rate and secret channel capacity are presented.