Methods and systems for encrypting and decrypting data are described. An exemplary system includes an optical transceiver that includes at least one of an encryption block and a decryption block. The optical transceiver also has at least one encryption and decryption key stored at the transceiver. The encryption block receives unencrypted data and performs encryption operations on the data using the encryption and decryption key. The decryption block receives encrypted data and performs a decryption operation using the encryption and decryption key.