Nimbus (cipher)

Nimbus
General
Designers	Alexis Machado
First published	2000
Cipher detail
Key sizes	128 bits
Block sizes	64 bits
Rounds	5
Best public cryptanalysis
Differential cryptanalysis can break Nimbus with 256 chosen plaintexts.

In cryptography, Nimbus is a block cipher invented by Alexis Machado in 2000. It was submitted to the NESSIE project, but was not selected.

The algorithm uses a 128-bit key. It operates on blocks of 64 bits and consists of 5 rounds of encryption. The round function is exceedingly simple. In each round the block is XORed with a subkey, the order of its bits is reversed, and then it is multiplied mod 2⁶⁴ by another subkey, which is forced to be odd.^[1]

Nimbus was broken by Vladimir Furman; he found a differential attack using only 256 chosen plaintexts.^[2]

References

^ Murphy, Sean; White, Juliette (2001-09-23). "Security Evaluation of NESSIE First Phase: 2.4.6 Nimbus" (PDF). p. 22. Retrieved 2018-09-13.
^ Eli Biham, Vladimir Furman (2000-11-29). "Differential Cryptanalysis of Nimbus". Fast Software Encryption. Lecture Notes in Computer Science. Vol. 2355. pp. 187–195. doi:10.1007/3-540-45473-X_16. ISBN 978-3-540-45473-1.

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Less common algorithms	ARIA Camellia CAST-128 GOST IDEA LEA RC5 RC6 SEED Skipjack TEA XTEA
Other algorithms	3-Way Adiantum Akelarre Anubis Ascon 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 Grand Cru Hasty Pudding cipher Hierocrypt ICE IDEA NXT Intel Cascade Cipher Iraqi Kalyna KASUMI KeeLoq KHAZAD Khufu and Khafre KN-Cipher Kuznyechik Ladder-DES 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 Prince Q RC2 REDOC Red Pike S-1 SAFER SAVILLE SC2000 SHACAL SHARK Simon Speck Spectr-H64 Square SXAL/MBAL Threefish Treyfer UES xmx XXTEA Zodiac
Design	Feistel network Key schedule Lai–Massey scheme Product cipher S-box P-box SPN Confusion and diffusion Round 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 Side-channel Timing Power-monitoring Electromagnetic Acoustic Differential-fault XSL Interpolation Partitioning Rubber-hose Black-bag Davies Rebound Weak key Tau Chi-square Time/memory/data tradeoff
Standardization	AES process CRYPTREC NESSIE NSA Suite B CNSA
Utilization	Initialization vector Mode of operation Padding

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Mathematics	Cryptographic hash function Block cipher Stream cipher Symmetric-key algorithm Authenticated encryption Public-key cryptography Quantum key distribution Quantum cryptography Post-quantum cryptography Message authentication code Random numbers Steganography
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