The Shannon Cipher System With a Guessing Wiretapper: General Sources
The Shannon cipher system is studied in the context of general sources using a notion of computational secrecy introduced by Merhav and Arikan. Bounds are derived on limiting exponents of guessing moments for general sources. The bounds are shown to be tight for i.i.d., Markov, and unifilar sources, thus recovering some known results. A close relationship between error exponents and correct decoding exponents for fixed rate source compression on the one hand and exponents for guessing moments on the other hand is established.
cipher systems secrecy error exponent correct decoding exponent fixed-rate source coding information spectrum key rate large deviations length function sources with memory