Patent ID: 7471790

Claim:
An encryption method comprising the steps of: modulating one-bit input data into a coded signal by associating said one-bit input data with a discrete value of at least two bits determined by a pseudo random number and a physical random number and for generating said discrete value as said coded signal based on a three-variable function for modulation; and channel-coding said coded signal and outputting said coded data channel-coded as encrypted data, wherein: the three-variable function, in which each combination includes a value of an input data selected as the one-bit input data from an input data stream, a value of the pseudo random number, and a value of the physical random number, and associated with one of plurality of discrete values serving as the coded signal, is previously determined by: 1) said coded signal is operable to be demodulated into said input data by said pseudo random number irrespective of the physical random number; 2) a number of cases where each of the plurality of discrete values is associated with a value of the input data being 1 is equal to a number of cases where each discrete value is associated with the value of the input data being 0; and 3) an equal number of different pseudo random numbers are associated with each pair of the value of the input data and discrete value.