On Secrecy Above Secrecy Capacity
Information theoretic security is being widely studied in recent times. It provides fundamental limits of secret communication. Unlike in cryptography, the information theoretic techniques are not based on complexity of computational hardness of certain problems. Information theoretic security can also be used in a system in addition to cryptographic techniques to add additional layers of protection to the information transmission or to achieve key agreement and/or distribution. Information theoretic formulations for 'Reliable communication' and 'Secrecy' were provided in classic papers of Shannon. A secret communication system model considers reliable transmission of information from the transmitter to the intended receiver and this information should not be decoded by the eavesdropper.