ENCRYPTION AND DECRYPTION METHOD AND DEVICE

An encryption method and device and a decryption method and device are provided, to resolve a problem that unconditional security of encrypted service data cannot be ensured in an existing service data encryption process and encryption processing of highly confidential service data cannot be implemented. The encryption device in the present invention obtains a quantum key and to-be-encrypted service data; encrypts the to-be-encrypted service data by using the quantum key, to generate a ciphertext; inserts the ciphertext into a specified byte in an OTN overhead byte, and performs encapsulation to obtain an OTN frame including the ciphertext; and converts the OTN frame from an electrical signal to an optical signal, and transmits the optical signal to a second OTN device. The service data is encrypted by using the quantum key, and therefore unconditional security of service data transmission can be ensured. In addition, the ciphertext is inserted into the specified byte in the OTN overhead byte, and therefore encryption processing of a highly confidential service can be implemented.