GOST in 417 bytes of PERL
© Vipul Ved Prakash, 1997-98. All Rights Reserved.
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#!/usr/bin/perl -s
sub F{$u=0;grep$u|=$S[$_][$_[0]>>$_*4&15]<<$_*4,reverse 0..7;$u<<11|$u>>21}sub R
{int$_[0]*rand}sub N{vec$_[0],$_[1]/4,32}$e=join'',<>;@b=@t=0..15;for(;$i<length
$p;$i+=4){srand($s^=N$p,$i)}while($c<8){grep{push@b,splice@b,R(9),5}@t;$R[$c]=R(
2**32);@{$S[$c++]}=@b}@h=0..7;@o=reverse@h;while($a<length$e){$v=N$e,$a;$w=N$e,(
$a+=8)-4;grep$q++%2?$v^=F$w+$K[$_]:($w^=F$v+$K[$_]) ,$d?(@h,(@o)x3):((@h)x3,@o);
$_.=pack N2,$w,$v}print
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SPECS USAGE
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Cipher GOST (28147-89). gostcrypt -e -p=password <plain.txt>
Mode Simple Substitution Mode. gostcrypt -d -p=password <crypt.txt>
Key Length 610 bits.
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Obfuscated version of the code, earned a 'dishonorable mention' in the 3rd
Obfuscated Perl Contest. You can admire the "leaping dolphin"
here. :-)
Soviet Encryption Algorithm
(GOST 28147-89)
GOST is a 64-bit symmetric cipher from the
former Soviet Union. It uses a 256 bit key
and some additional secret information in
form of SBOX permutations.
The details of the
algorithm were published in 1990 as the Soviet Standard - GOST 28147-89.
The algorithm provides flexible security (bad SBOXes can compromise the
plain text) and can be implemented in both hardware and software.
Papers
Original GOST Specs translated in English by Josef Pieprzyk
and Leonid Tombak
GOST Algorithm specs, GOST in Simple
Substitution Mode, Stream Mode, Stream Mode with feedback and
Authentication Mode.
Further Comments on GOST : Mathematical analysis
Description of GOST, General Properties of GOST, Avalanche Characterstic
of GOST adder, Cyclic shifts in GOST and Selection of SBOXes.
English Translation of GOST Specs by Aleksandr Malchik Algorithm Structure,
Electronic Codebook Mode, Output Feedback Mode, Cipher Feedback Mode,
Authentication Mode, Flowcharts.
GOST Hash Function
English translation of the GOST Hash function standard (GOST R 34.11-94)
by Michael Roe of Cambridge University. Incomplete.
Software
Gostcrypt - GOST in 417 bytes of PERL
Simple Substitution Mode. The KSU (256 bit Key Unit) and
SBOX permutations are generated from the pass phrase. Vipul Ved Prakash, 1997.
Gost.pm
A PERL 5 Module based on gostcrypt. Still undocumented. Vipul Ved Prakash, 1997.
Gost.c.
C Implementation.
GOST for Windows
GOST implementation for Windows 3.x, Divya Mahajan and Vipul Ved Prakash, 1995.
GOST for DOS
GOST implementation for MS-DOS. Vipul Ved Prakash, 1995.
Web design and architecture, Vipul Ved Prakash.
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