openssl/engines/ccgost/gosthash.c
2012-08-13 16:39:42 +00:00

255 lines
6 KiB
C

/**********************************************************************
* gosthash.c *
* Copyright (c) 2005-2006 Cryptocom LTD *
* This file is distributed under the same license as OpenSSL *
* *
* Implementation of GOST R 34.11-94 hash function *
* uses on gost89.c and gost89.h Doesn't need OpenSSL *
**********************************************************************/
#include <string.h>
#include "gost89.h"
#include "gosthash.h"
/* Use OPENSSL_malloc for memory allocation if compiled with
* -DOPENSSL_BUILD, and libc malloc otherwise
*/
#ifndef MYALLOC
# ifdef OPENSSL_BUILD
# include <openssl/crypto.h>
# define MYALLOC(size) OPENSSL_malloc(size)
# define MYFREE(ptr) OPENSSL_free(ptr)
# else
# define MYALLOC(size) malloc(size)
# define MYFREE(ptr) free(ptr)
# endif
#endif
/* Following functions are various bit meshing routines used in
* GOST R 34.11-94 algorithms */
static void swap_bytes (byte *w, byte *k)
{
int i,j;
for (i=0;i<4;i++)
for (j=0;j<8;j++)
k[i+4*j]=w[8*i+j];
}
/* was A_A */
static void circle_xor8 (const byte *w, byte *k)
{
byte buf[8];
int i;
memcpy(buf,w,8);
memmove(k,w+8,24);
for(i=0;i<8;i++)
k[i+24]=buf[i]^k[i];
}
/* was R_R */
static void transform_3 (byte *data)
{
unsigned short int acc;
acc=(data[0]^data[2]^data[4]^data[6]^data[24]^data[30])|
((data[1]^data[3]^data[5]^data[7]^data[25]^data[31])<<8);
memmove(data,data+2,30);
data[30]=acc&0xff;
data[31]=acc>>8;
}
/* Adds blocks of N bytes modulo 2**(8*n). Returns carry*/
static int add_blocks(int n,byte *left, const byte *right)
{
int i;
int carry=0;
int sum;
for (i=0;i<n;i++)
{
sum=(int)left[i]+(int)right[i]+carry;
left[i]=sum & 0xff;
carry=sum>>8;
}
return carry;
}
/* Xor two sequences of bytes */
static void xor_blocks (byte *result,const byte *a,const byte *b,size_t len)
{
size_t i;
for (i=0;i<len;i++) result[i]=a[i]^b[i];
}
/*
* Calculate H(i+1) = Hash(Hi,Mi)
* Where H and M are 32 bytes long
*/
static int hash_step(gost_ctx *c,byte *H,const byte *M)
{
byte U[32],W[32],V[32],S[32],Key[32];
int i;
/* Compute first key */
xor_blocks(W,H,M,32);
swap_bytes(W,Key);
/* Encrypt first 8 bytes of H with first key*/
gost_enc_with_key(c,Key,H,S);
/* Compute second key*/
circle_xor8(H,U);
circle_xor8(M,V);
circle_xor8(V,V);
xor_blocks(W,U,V,32);
swap_bytes(W,Key);
/* encrypt second 8 bytes of H with second key*/
gost_enc_with_key(c,Key,H+8,S+8);
/* compute third key */
circle_xor8(U,U);
U[31]=~U[31]; U[29]=~U[29]; U[28]=~U[28]; U[24]=~U[24];
U[23]=~U[23]; U[20]=~U[20]; U[18]=~U[18]; U[17]=~U[17];
U[14]=~U[14]; U[12]=~U[12]; U[10]=~U[10]; U[ 8]=~U[ 8];
U[ 7]=~U[ 7]; U[ 5]=~U[ 5]; U[ 3]=~U[ 3]; U[ 1]=~U[ 1];
circle_xor8(V,V);
circle_xor8(V,V);
xor_blocks(W,U,V,32);
swap_bytes(W,Key);
/* encrypt third 8 bytes of H with third key*/
gost_enc_with_key(c,Key,H+16,S+16);
/* Compute fourth key */
circle_xor8(U,U);
circle_xor8(V,V);
circle_xor8(V,V);
xor_blocks(W,U,V,32);
swap_bytes(W,Key);
/* Encrypt last 8 bytes with fourth key */
gost_enc_with_key(c,Key,H+24,S+24);
for (i=0;i<12;i++)
transform_3(S);
xor_blocks(S,S,M,32);
transform_3(S);
xor_blocks(S,S,H,32);
for (i=0;i<61;i++)
transform_3(S);
memcpy(H,S,32);
return 1;
}
/* Initialize gost_hash ctx - cleans up temporary structures and
* set up substitution blocks
*/
int init_gost_hash_ctx(gost_hash_ctx *ctx, const gost_subst_block *subst_block)
{
memset(ctx,0,sizeof(gost_hash_ctx));
ctx->cipher_ctx = (gost_ctx *)MYALLOC(sizeof(gost_ctx));
if (!ctx->cipher_ctx)
{
return 0;
}
gost_init(ctx->cipher_ctx,subst_block);
return 1;
}
/*
* Free cipher CTX if it is dynamically allocated. Do not use
* if cipher ctx is statically allocated as in OpenSSL implementation of
* GOST hash algroritm
*
*/
void done_gost_hash_ctx(gost_hash_ctx *ctx)
{
/* No need to use gost_destroy, because cipher keys are not really
* secret when hashing */
MYFREE(ctx->cipher_ctx);
}
/*
* reset state of hash context to begin hashing new message
*/
int start_hash(gost_hash_ctx *ctx)
{
if (!ctx->cipher_ctx) return 0;
memset(&(ctx->H),0,32);
memset(&(ctx->S),0,32);
ctx->len = 0L;
ctx->left=0;
return 1;
}
/*
* Hash block of arbitrary length
*
*
*/
int hash_block(gost_hash_ctx *ctx,const byte *block, size_t length)
{
const byte *curptr=block;
const byte *barrier=block+(length-32);/* Last byte we can safely hash*/
if (ctx->left)
{
/*There are some bytes from previous step*/
unsigned int add_bytes = 32-ctx->left;
if (add_bytes>length)
{
add_bytes = length;
}
memcpy(&(ctx->remainder[ctx->left]),block,add_bytes);
ctx->left+=add_bytes;
if (ctx->left<32)
{
return 1;
}
curptr=block+add_bytes;
hash_step(ctx->cipher_ctx,ctx->H,ctx->remainder);
add_blocks(32,ctx->S,ctx->remainder);
ctx->len+=32;
ctx->left=0;
}
while (curptr<=barrier)
{
hash_step(ctx->cipher_ctx,ctx->H,curptr);
add_blocks(32,ctx->S,curptr);
ctx->len+=32;
curptr+=32;
}
if (curptr!=block+length)
{
ctx->left=block+length-curptr;
memcpy(ctx->remainder,curptr,ctx->left);
}
return 1;
}
/*
* Compute hash value from current state of ctx
* state of hash ctx becomes invalid and cannot be used for further
* hashing.
*/
int finish_hash(gost_hash_ctx *ctx,byte *hashval)
{
byte buf[32];
byte H[32];
byte S[32];
ghosthash_len fin_len=ctx->len;
byte *bptr;
memcpy(H,ctx->H,32);
memcpy(S,ctx->S,32);
if (ctx->left)
{
memset(buf,0,32);
memcpy(buf,ctx->remainder,ctx->left);
hash_step(ctx->cipher_ctx,H,buf);
add_blocks(32,S,buf);
fin_len+=ctx->left;
}
memset(buf,0,32);
bptr=buf;
fin_len<<=3; /* Hash length in BITS!!*/
while(fin_len>0)
{
*(bptr++)=(byte)(fin_len&0xFF);
fin_len>>=8;
};
hash_step(ctx->cipher_ctx,H,buf);
hash_step(ctx->cipher_ctx,H,S);
memcpy(hashval,H,32);
return 1;
}