Spread spectrum signal generation method, spread spectrum signal generator, stream encryption method, and stream enciphered codes communication method

A spread spectrum signal generator comprising:

• a program storage unit for storing a program for execution of operations depending on expressions (1) to (3),
• Logistic mapping:
• x(t+1)=4x(t){1−x(t)} (1),
• Feedback:
• x(t)=x(t+1) (2), and
• Isomorphic transform and quantization:
• y(t)=[{2/π·arc sin {square root over ( )}x(t)}·2n] (3)
• where, t is a discrete time, x(t) is an internal state of a chaos given as a real number with double-precision normalized between ‘0’ and ‘1’, and [ ] is an arithmetic operator representing a round-off operation of a decimal fraction of a value in the [ ],
• a database for storing a quantization resolution n=1 and an initial value x(0);
• and
• an arithmetic processing unit for starting an operation by substituting to the expression (1) the initial value x(0) stored in the database, having a resultant value based on the expression (2) again as an input to the expression (1), determining a time series x(t)−t by repeating such operations, substituting to the expression (3) the quantization resolution n=1 stored in the database, determining an isomorphic transform and quantization based on the expression (3) in correspondence to the time series x(t)−t, determining a time series y(t)−t from the determined isomorphic transform and quantization, generating a spread spectrum signal having, as a period thereof, a binary code sequence y(t) arbitrarily cut out of the time series y(t)−t.