SXAL/MBAL

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:

1. Pre-whitening
2. F_m: An expanded version of SXAL applied to the entire message
3. SXAL the block consisting of the first 4 and last 4 bytes
4. Reverse the byte order of the entire message
5. F_m
6. Reverse
7. SXAL the ends
8. F_m
9. Post-whitening

MBAL has been shown to be susceptible to both differential cryptanalysis and linear cryptanalysis.^[1]

References

1. 1 2 Schneier, Bruce (1996). Applied Cryptography (2nd ed.). John Wiley & Sons. p. 344. ISBN 0-471-11709-9. 

External links

• ISO/IEC9979-0012 Register Entry (PDF), registered 23 October 1995
• U.S. Patent 6,038,321, a patent on a communications system using SXAL/MBAL for encryption. Includes a description of SXAL/MBAL.
• Kobayashi, Kunio; Kazumaro Aoki (April 1999). "On linear cryptanalysis of MBAL ciphers (abstract)". Electronics and Communications in Japan (Part III: Fundamental Electronic Science) (Wiley Interscience) 82 (10): 1–8. ISSN 1520-6440. Retrieved 4 November 2009. 

Block ciphers (security summary) Common algorithms AES Blowfish DES (Internal Mechanics, Triple DES) Serpent Twofish Less common algorithms Camellia CAST-128 IDEA RC2 RC5 SEED ARIA Skipjack TEA XTEA Other algorithms 3-Way Akelarre Anubis BaseKing BassOmatic BATON BEAR and LION CAST-256 Chiasmus CIKS-1 CIPHERUNICORN-A CIPHERUNICORN-E CLEFIA CMEA Cobra COCONUT98 Crab Cryptomeria/C2 CRYPTON CS-Cipher DEAL DES-X DFC E2 FEAL FEA-M FROG G-DES GOST Grand Cru Hasty Pudding cipher Hierocrypt ICE IDEA NXT Intel Cascade Cipher Iraqi KASUMI KeeLoq KHAZAD Khufu and Khafre KN-Cipher Ladder-DES Libelle LOKI (97, 89/91) Lucifer M6 M8 MacGuffin Madryga MAGENTA MARS Mercy MESH MISTY1 MMB MULTI2 MultiSwap New Data Seal NewDES Nimbus NOEKEON NUSH PRESENT Q RC6 REDOC Red Pike S-1 SAFER SAVILLE SC2000 SHACAL SHARK Simon SMS4 Speck Spectr-H64 Square SXAL/MBAL Threefish Treyfer UES Xenon xmx XXTEA Zodiac Design Feistel network Key schedule Lai-Massey scheme Product cipher S-box P-box SPN Avalanche effect Block size Key size Key whitening (Whitening transformation) Attack (cryptanalysis) Brute-force (EFF DES cracker) MITM (Biclique attack, 3-subset MITM attack) Linear (Piling-up lemma) Differential (Impossible Truncated Higher-order) Differential-linear Distinguishing (Known-key) Integral/Square Boomerang Mod n Related-key Slide Rotational Timing XSL Interpolation Partitioning Davies' Rebound Weak key Tau Chi-square Time/memory/data tradeoff Standardization AES process CRYPTREC NESSIE Utilization Initialization vector Mode of operation Padding Cryptography History of cryptography Cryptanalysis Outline of cryptography Symmetric-key algorithm Block cipher Stream cipher Public-key cryptography Cryptographic hash function Message authentication code Random numbers Steganography Portal