7. Glossary

Encryption

In cryptography, encryption is the process of transforming information so that, ideally, only authorized parties can decrypt it (the reverse operation). This process converts the original representation of the information, known as plaintext, into an alternative form called ciphertext, using an encryption algorithm and a secret key. When the parties involved in the communication share the same key, the encryption is said to be symmetric.

Stream cipher

Stream cipher is a symmetric-key encryption method in which plaintext characters are combined with a pseudorandom sequence (called a keystream). Each character of the plaintext is encrypted one by one with the corresponding character of the key sequence to produce a ciphertext sequence. In practice, the base character is typically a bit, and the combination...