private key

A cryptographic key, used with a public key cryptographic algorithm, that is uniquely associated with an entity and is not made public. In an asymmetric (public) cryptosystem, the private key is associated with a public key. Depending on the algorithm, the private key may be used, for example, to: 1) Compute the corresponding public key, 2) Compute a digital signature that may be verified by the corresponding public key, 3) Decrypt keys that were encrypted by the corresponding public key, or 4) Compute a shared secret during a key-agreement transaction.