Key (cryptography)

In cryptography, a key is some set data which, in combination with a cryptographic algorithm, introduces or removes the concealment applied to plaintext or taken to ciphertext. This discussion deals with the nature of keys (e.g., binary strings of length $N$, text phrases), the basis of generating good and bad keys, the types of keys (e.g., session key, key distribution key, public key, key generating key)

Key management is a related but separate discipline of secure distribution of keys and entering them into cryptosystem, as well as technical administration practices such as authentication#authenticating keys, revoking keys, and parameterizing session-level key changes.