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In cryptography, SXAL (Substitution Xor ALgorithm, sometimes called SXAL8) is a block cipher designed in 1993 by Yokohama-based Laurel Intelligent Systems. It is normally used in a special mode of operation called MBAL (Multi Block ALgorithm). SXAL/MBAL has been used for encryption in a number of Japanese PC cards and smart cards. SXAL is an 8-round substitution-permutation network with block size and key size of 64 bits each. All operations are byte-oriented. The algorithm uses a single 8×8-bit S-box ''K'', designed so that both K(X) and X XOR K(X) are injective functions. In each round, the bytes of the block are first permuted. Then each byte is XORed with a key byte and an earlier ciphertext byte, processed through the S-box, and XORed with the previous plaintext byte. The key schedule is rather complex, processing the key with SXAL itself, beginning with a null key and using permuted intermediate results as later keys. ==MBAL== MBAL is an encryption algorithm built using SXAL that can be applied to messages any number of bytes in length (at least 8). It uses two 64-bit extended keys for key whitening on the first 64 bits. The algorithm consists of 9 steps: # Pre-whitening # Fm: An expanded version of SXAL applied to the entire message # SXAL the block consisting of the first 4 and last 4 bytes # Reverse the byte order of the entire message # Fm # Reverse # SXAL the ends # Fm # Post-whitening MBAL has been shown to be susceptible to both differential cryptanalysis and linear cryptanalysis.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「SXAL/MBAL」の詳細全文を読む スポンサード リンク
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