Security of optical communication systems is important to government and commercial users. If an eavesdropper can receive and decrypt an encrypted message, they can access and steal confidential information. Stream cipher-based cryptographic systems encrypt and decrypt messages using keys; however, they are vulnerable to attack if a key is used more than once. An adversary with sufficient computing power can analyze encryption traffic to break the cipher. The Inventors have developed a cryptographic scheme proven to be much more secure for applications in optical networks, making it impossible for an illegitimate receiver to break the cipher without sifting through a practically impossible amount of traffic.