The secret key (SK) is the private, secret key in asymmetric encryption. It is known only to the owner and contains the combinations with which information can be encrypted and decrypted in the public key procedure.
In addition, the private key can also be used to generate the public key, the revocation certificate, and to sign e-mails.
In order for each communication partner to be able to encrypt and decrypt messages in symmetric encryption procedures, the communication partners share a secret key. Symmetric encryption, which uses only one secret key, is also known as Secret Key Encryption. Asymmetric encryption works with both keys, the private key and the public key.