Editing GOST (block cipher) (section)

{{short description|Soviet/Russian national standard block cipher}}
{{Infobox encryption method
|name           = GOST 28147-89 (Magma)
|image          = [[File:GOSTDiagram.png|240px|center]]
|caption        = Diagram of GOST
|designers      = [[USSR]], [[KGB]], 8th Department
|publish date   = 1994-05-23 (declassified)
|series         = 
|derived from   = 
|derived to     = [[GOST (hash function)|GOST hash function]], [[Kuznyechik]]
|related to     = 
|certification  = [[GOST|GOST standard]]
|key size       = 256 bits
|security claim = 
|block size     = 64 bits
|structure      = [[Feistel network]]
|rounds         = 32
|cryptanalysis  = In 2011 several authors discovered more significant flaws in GOST, being able to attack the full 32-round GOST with arbitrary keys for the first time. It has even been called "a deeply flawed cipher" by [[Nicolas Courtois]].<ref>
{{cite journal
 |last=Courtois
 |first=Nicolas T.
 |title=Security Evaluation of GOST 28147-89 In View Of International Standardisation
 |url=http://eprint.iacr.org/2011/211
 |journal=Cryptology ePrint Archive
 |publisher=[[International Association for Cryptologic Research|IACR]]
 |date=9 May 2011
 |quote=Until 2011 researchers unanimously agreed that GOST could or should be very secure, which was summarised in 2010 in these words: despite considerable cryptanalytic efforts spent in the past 20 years, GOST is still not broken". Unhappily, it was recently discovered that GOST can be broken and is a deeply flawed cipher}}
</ref>
}}

The '''GOST block cipher''' ('''Magma'''), defined in the standard '''GOST 28147-89''' (RFC 5830), is a Soviet and Russian government standard [[symmetric key]] [[block cipher]] with a block size of 64 bits. The original standard, published in 1989, did not give the cipher any name, but the most recent revision of the standard, '''GOST R 34.12-2015''' (RFC 7801, RFC 8891), specifies that it may be referred to as Magma.<ref name="std2015"/> The [[GOST (hash function)|GOST hash function]] is based on this cipher. The new standard also specifies a new 128-bit block cipher called [[Kuznyechik]]. 

Developed in the 1970s, the standard had been marked "Top Secret" and then downgraded to "Secret" in 1990. Shortly after the dissolution of the [[USSR]], it was declassified and it was released to the public in 1994. GOST 28147 was a Soviet alternative to the [[United States]] standard algorithm, [[Data Encryption Standard|DES]].<ref name=fleischmann2009>
{{cite journal
 |last=Fleischmann
 |first=Ewan
 |author2=Gorski, Michael |author3=Hühne, Jan-Hendrik |author4= Lucks, Stefan
 |title=Key Recovery Attack on Full GOST Block Cipher with Zero Time and Memory
 |journal=Published as ISO/IEC JTC
 |year=2009
 |volume=1}}
</ref> Thus, the two are very similar in structure.