Understanding symmetric encryption
Symmetric encryption is used for encrypting data with an encryption key. Note that an encryption key is not the same as a password, but an encryption key can be derived from a password. How to do so will be explained in a Chapter 5, Derivation of an Encryption Key from a Password.
Symmetric encryption is called symmetric because the same key is used both for encryption and decryption operations. There is also asymmetric encryption, where different keys (public and private) are used for encryption and decryption. Asymmetric encryption will be covered in Chapter 6, Asymmetric Encryption and Decryption.
In order to symmetrically encrypt something, you have to use a symmetric encryption algorithm. This kind of algorithm is also called a cipher. It is worth noting the term cipher has a broad meaning and can refer to any encryption or encryption-related algorithm, including algorithms for symmetric and asymmetric encryption, message digests, and even...
