and the Twofish Known Answer Tests (files ecb_iv.txt, ecb_tbl.txt, ecb_vk.txt and ecb_vt.txt).   Cipher details   top RC4 , AES , Serpent , Twofish , Caesar and Swap are symmetric ciphers. The encryption key and the decryption key are the same. The RC4a cipher modifies the RC4 cipher to circumvent its