A communication system includes encoding and decoding devices. The encoding device includes an encrypting module adapted for encrypting an original signal into an encrypted signal, and an error correction encoding module coupled to the encrypting module for receiving the encrypted signal therefrom, and generating an output signal by performing error correction encoding on the encrypted signal. The decoding device includes an error correction decoding module for receiving an input signal via a transmission channel, and a decrypting module. The input signal is a result of the output signal combined with noise. The error correction decoding module generates a recovery signal from the input signal by performing error correction decoding on the input signal. The decrypting module is coupled to the error correction decoding module for receiving the recovery signal therefrom, and generates a decrypted signal that corresponds to the original signal by decrypting a portion of the recovery signal.