Special Edition Using Java™ 2 Enterprise Edition

Encryption Terminology

When you deal with encryption software, you'll probably encounter a few terms you might not have heard before. First of all, as you have already seen, a cipher is an encryption algorithm. The encrypted data is called ciphertext, whereas the unencrypted data is called plaintext. A key is a piece of information used to encrypt or decrypt the data but is not part of the data.

A stream cipher is a simple single-character-in, single-character-out cipher. That is, it performs the encryption one character at a time. Each time a stream cipher reads a character, it uses the key and accumulated data from the other characters it has processed to figure out how to scramble the next byte of data. Unlike some of the simple ciphers you ...