Abstract: “Networked computers are omnipresent, and are subject to attack, misuse, and abuse. One method to counteract the ever increasing cyber threat is to provide new symmetric algorithms satisfies the security requirements. In this paper we introduce new symmetric system based on Lucifer cryptosystem. The plaintext block is divided into basic sub-blocks each of thirty-two bits in length. The new Proposal can encrypt blocks of plaintext of length 256 bits into blocks of the same length. The key length is 512 bits. It uses new S-boxes implemented using Gold Exponent function one of APN (Almost Perfect Nonlinear) function. In this system, we try to get the minimum correlation between plaintext and ciphertext, highly avalanche effect and defeat the frequency analysis and most well-known attacks. The new algorithm is compared with Lucifer cryptosystem and gives excellent results from the viewpoint of the security characteristics and the statistics of the ciphertext. Also, we apply the randomness t”

Keywords: Lucifer cryptographic system, APN, Gold exponent, frequency analysis