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GOST hash of a Little Endian stream

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orignal 2017-04-07 11:17:40 -04:00
parent 4e1fcbb706
commit 987688f196
2 changed files with 96 additions and 0 deletions
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87
Gost.cpp
View File

@ -438,5 +438,92 @@ namespace crypto
memset (iv, 0, 64);
H (iv, buf, len, digest);
}
// reverse order
struct GOSTR3411_2012_CTX
{
GOST3411Block h, N, s, m;
size_t len;
bool is512;
};
GOSTR3411_2012_CTX * GOSTR3411_2012_CTX_new ()
{
return new GOSTR3411_2012_CTX;
}
void GOSTR3411_2012_CTX_free (GOSTR3411_2012_CTX * ctx)
{
delete ctx;
}
void GOSTR3411_2012_CTX_Init (GOSTR3411_2012_CTX * ctx, bool is512)
{
uint8_t iv[64];
memset (iv, is512 ? 0 : 1, 64);
memcpy (ctx->h.buf, iv, 64);
memset (ctx->N.buf, 0, 64);
memset (ctx->s.buf, 0, 64);
ctx->len = 0;
ctx->is512 = is512;
}
void GOSTR3411_2012_CTX_Update (const uint8_t * buf, size_t len, GOSTR3411_2012_CTX * ctx)
{
if (!len) return;
if (ctx->len > 0) // something left from buffer
{
size_t l = 64 - ctx->len;
if (len < l) l = len;
for (size_t i = 0; i < l; i++)
ctx->m.buf[ctx->len + i] = buf[l-i-1]; // invert
ctx->len += l; len -= l; buf += l;
ctx->h = gN (ctx->N, ctx->h, ctx->m);
ctx->N.Add (512);
ctx->s = ctx->m + ctx->s;
}
while (len >= 64)
{
for (size_t i = 0; i < 64; i++)
ctx->m.buf[i] = buf[63-i]; // invert
len -= 64; buf += 64;
ctx->h = gN (ctx->N, ctx->h, ctx->m);
ctx->N.Add (512);
ctx->s = ctx->m + ctx->s;
}
if (len > 0) // carry remaining
{
for (size_t i = 0; i < len; i++)
ctx->m.buf[i] = buf[len-i-1]; // invert
}
ctx->len = len;
}
void GOSTR3411_2012_CTX_Finish (uint8_t * digest, GOSTR3411_2012_CTX * ctx)
{
GOST3411Block m;
size_t padding = 64 - ctx->len;
if (padding)
{
memset (m.buf, 0, padding - 1);
m.buf[padding - 1] = 1;
}
memcpy (m.buf + padding, ctx->m.buf, ctx->len);
ctx->h = gN (ctx->N, ctx->h, m);
ctx->N.Add (ctx->len*8);
ctx->s = m + ctx->s;
GOST3411Block N0;
memset (N0.buf, 0, 64);
ctx->h = gN (N0, ctx->h, ctx->N);
ctx->h = gN (N0, ctx->h, ctx->s);
size_t sz = ctx->is512 ? 64 : 32;
for (size_t i = 0; i < sz; i++)
digest[i] = ctx->h.buf[sz - i - 1];
}
}
}

9
Gost.h
View File

@ -45,8 +45,17 @@ namespace crypto
std::unique_ptr<GOSTR3410Curve>& GetGOSTR3410Curve (GOSTR3410ParamSet paramSet);
// Big Endian
void GOSTR3411_2012_256 (const uint8_t * buf, size_t len, uint8_t * digest);
void GOSTR3411_2012_512 (const uint8_t * buf, size_t len, uint8_t * digest);
// Little Endian
struct GOSTR3411_2012_CTX;
GOSTR3411_2012_CTX * GOSTR3411_2012_CTX_new ();
void GOSTR3411_2012_CTX_Init (GOSTR3411_2012_CTX * ctx, bool is512 = true);
void GOSTR3411_2012_CTX_Update (const uint8_t * buf, size_t len, GOSTR3411_2012_CTX * ctx);
void GOSTR3411_2012_CTX_Finish (uint8_t * digest, GOSTR3411_2012_CTX * ctx);
void GOSTR3411_2012_CTX_free (GOSTR3411_2012_CTX * ctx);
}
}