Definitions[]
A symmetric key is an
| “ | [e]ncryption methodology in which the encryptor and decryptor use the same key, which must be kept secret.[1] | ” |
| “ | [a] cryptographic key that is used to perform both the cryptographic operation and its inverse, for example to encrypt plaintext and decrypt ciphertext, or create a message authentication code and to verify the code.[2] | ” |
Overview[]
Both the sending and receiving parties must know the secret key that they will use to communicate. Secret-key algorithms can encrypt and decrypt relatively quickly, but systems that use only secret keys can be difficult to manage because they require a courier, registered mail, or other secure means for distributing keys.