Explanation: Modern encryption uses many of these methods in combination and in conjunction with algorithms that use a series of programmed calculations and transformations to derive strong keys. Modern encryption is classified as Symmetric or Asymmetric. Symmetric encryption allows the use of the same key (a single key) to encrypt and to decrypt the data/message; Asymmetric encryption allows the use of a split (two-part) key to encrypt and to decrypt the data/message. Using asymmetric encryption algorithms, the owner of the key gives out a 'public' key that may be used by anyone to encrypt a message; the second half of the key (private key) is only know to the owner of the key and is used by asymmetric encryption algorithms to decrypt the message. Using two-part (public and private) keys provides a greater degree of flexibility, while maintaining a high degree of security, since anyone may use the public key and only the owner of the private key may read the message.