Abstract: The invention is directed to a symmetric encoding and decoding architecture for a communication system that may be implemented using multiple encoding levels. By changing the number of levels used, the system may be adapted to the user's speed and security requirements. Cryptoanalysis techniques attacking the encoding process may yield multiple meaningful messages, without the ability of the attacker to determine which message is the correct one. The encrypted messages may also be compressed according to an algorithm that is effective even for small message sizes, and an exclusive-OR (XOR) function may be applied to the result to thwart an attack by a party that knows the compression algorithm.