The two most frequently used encryption methods are asymmetrical encryption, also known as public key encryption, and symmetrical encryption.

Symmetrical and asymmetrical encryption are often used in combination. The source text is encrypted using a symmetrical cypher with a randomly generated symmetrical key. This symmetrical key is then encrypted using a public key of an asymmetrical cypher and delivered, together with the encrypted data, to the specified recipient. The data can only be deciphered by the holder of the private key to the asymmetrical cypher used.