FEAL - Fast Data Encipherment Algorithm

This paper discusses the design of the fast data encipherment algorithm (FEAL). FEAL is a conventional encipherment algorithm using the same key for enciphering and deciphering. It is a block cipher algorithm which produces 64 bit ciphertext from 64 plaintext, using a 64-bit key. The main feature of the cipher processing in FEAL is that it is based on 8-bit data manipulations such as addition with modulo 256, and data cycle and data transfer commands for 1-byte. The program performance of FEAL is improved greatly compared with that of DES. The security of FEAL is based on the characteristic value representing the trace of the plaintext and ciphering key remaining in the ciphertext, as well as on the algorithm structure.