SMASH (hash)

SMASH
General
Designers	Lars R. Knudsen
First published	2005
Detail
Digest sizes	256 or 512 bits
Best public cryptanalysis
Collision,^[1] Second Preimage^[2]

SMASH is a cryptographic hash function which was created by Lars R. Knudsen.^[3] SMASH comes in two versions: 256-bit and 512-bit. Each version was supposed to rival SHA-256 and SHA-512, respectively, however, shortly after the SMASH presentation at FSE 2005, an attack vector against SMASH was discovered which left the hash broken.

Specifications

The message length was limited to less than 2¹²⁸ for SMASH-256 and 2²⁵⁶ for SMASH-512.

Definition

Input: 256/512-bit message blocks $m_1, m_2, ... ,m_t$ and $\theta \in GF(2^n)$

$h_0 = f(iv) \oplus iv$
$h_i = h(h_{i-1},m_i) = f(h_{i_1}\oplus m_i) \oplus m_i \oplus \theta m_i$
$h_{t+1} = f(h_t) \oplus h_t$

The function f is a complex compression function consisting of H-Rounds and L-Rounds using S-boxes, linear diffusion and variable rotations, details can be found here ^[3]

Details

The S-boxes in SMASH are derived versions from the Serpent ones.

References

↑ Pramstaller, Norbert; Rechberger, Christian; Rijmen, Vincent (2006). "Breaking a New Hash Function Design Strategy Called SMASH". Lecture Notes in Computer Science 3897: 233–244. doi:10.1007/11693383_16.
↑ Lamberger, Mario; Pramstaller, Norbert; Rechberger, Christian; Rijmen, Vincent (2006). "Second Preimages for SMASH". Lecture Notes in Computer Science 4377: 101–111. doi:10.1007/11967668_7.
1 2 Knudsen, Lars R.: SMASH - A Cryptographic Hash Function, Accessed 23 November 2009

Hash functions & message authentication codes

Security summary

Common functions	MD5 SHA-1 SHA-2 SHA-3/Keccak

SHA-3 finalists	BLAKE Grøstl JH Skein Keccak (winner)

Other functions	FSB ECOH GOST HAS-160 HAVAL Kupyna LM hash MDC-2 MD2 MD4 MD5 MD6 N-Hash RadioGatún RIPEMD SipHash Snefru Streebog SWIFFT Tiger VSH WHIRLPOOL

MAC algorithms	DAA CBC-MAC HMAC OMAC/CMAC PMAC VMAC UMAC Poly1305

Authenticated encryption modes	CCM CWC EAX GCM IAPM OCB

Attacks	Collision attack Preimage attack Birthday attack Brute force attack Rainbow table Side-channel attack Length extension attack

Design	Avalanche effect Hash collision Merkle–Damgård construction

Standardization	CRYPTREC NESSIE NIST hash function competition

Utilization	Salt Key stretching Message authentication

Key derivation functions	bcrypt crypt(3) (DES) PBKDF2 scrypt Argon2

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

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