A large random number that is used in a two-part cryptographic system such as RSA. The private key is used to create its public key counterpart, and although the private key is kept hidden, the public key can be published anywhere (website, email, etc.).
Private Key vs. Secret Key
Sometimes the terms private key and secret key are used synonymously because the private key is kept in secret. However, secret key cryptography is a different system that uses the same key at both ends (see
secret key cryptography). See
public key cryptography and
RSA.
Encrypt Decrypt
Public Key Private key Public key
Cryptography Public key Private key
Secret Key
Cryptography Private key Private key