/*
* Copyright(C) 2006 Cameron Rich
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**
* SHA1 implementation - as defined in FIPS PUB 180-1 published April 17, 1995.
* This code was originally taken from RFC3174
*/
#include <string.h>
#include "crypto.h"
/*
* Define the SHA1 circular left shift macro
*/
#define SHA1CircularShift(bits,word) \
(((word) << (bits)) | ((word) >> (32-(bits))))
/* ----- static functions ----- */
static void SHA1PadMessage(SHA1_CTX *ctx);
static void SHA1ProcessMessageBlock(SHA1_CTX *ctx);
/**
* Initialize the SHA1 context
*/
void SHA1Init(SHA1_CTX *ctx)
{
ctx->Length_Low = 0;
ctx->Length_High = 0;
ctx->Message_Block_Index = 0;
ctx->Intermediate_Hash[0] = 0x67452301;
ctx->Intermediate_Hash[1] = 0xEFCDAB89;
ctx->Intermediate_Hash[2] = 0x98BADCFE;
ctx->Intermediate_Hash[3] = 0x10325476;
ctx->Intermediate_Hash[4] = 0xC3D2E1F0;
}
/**
* Accepts an array of octets as the next portion of the message.
*/
void SHA1Update(SHA1_CTX *ctx, const uint8_t *msg, int len)
{
while (len--)
{
ctx->Message_Block[ctx->Message_Block_Index++] = (*msg & 0xFF);
ctx->Length_Low += 8;
if (ctx->Length_Low == 0)
{
ctx->Length_High++;
}
if (ctx->Message_Block_Index == 64)
{
SHA1ProcessMessageBlock(ctx);
}
msg++;
}
}
/**
* Return the 160-bit message digest into the user's array
*/
void SHA1Final(SHA1_CTX *ctx, uint8_t *digest)
{
int i;
SHA1PadMessage(ctx);
memset(ctx->Message_Block, 0, 64);
ctx->Length_Low = 0; /* and clear length */
ctx->Length_High = 0;
for (i = 0; i < SHA1_SIZE; i++)
{
digest[i] = ctx->Intermediate_Hash[i>>2] >> 8 * ( 3 - ( i & 0x03 ) );
}
}
/**
* Process the next 512 bits of the message stored in the array.
*/
static void SHA1ProcessMessageBlock(SHA1_CTX *ctx)
{
const uint32_t K[] = { /* Constants defined in SHA-1 */
0x5A827999,
0x6ED9EBA1,
0x8F1BBCDC,
0xCA62C1D6
};
int t; /* Loop counter */
uint32_t temp; /* Temporary word value */
uint32_t W[80]; /* Word sequence */
uint32_t A, B, C, D, E; /* Word buffers */
/*
* Initialize the first 16 words in the array W
*/
for (t = 0; t < 16; t++)
{
W[t] = ctx->Message_Block[t * 4] << 24;
W[t] |= ctx->Message_Block[t * 4 + 1] << 16;
W[t] |= ctx->Message_Block[t * 4 + 2] << 8;
W[t] |= ctx->Message_Block[t * 4 + 3];
}
for (t = 16; t < 80; t++)
{
W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
}
A = ctx->Intermediate_Hash[0];
B = ctx->Intermediate_Hash[1];
C = ctx->Intermediate_Hash[2];
D = ctx->Intermediate_Hash[3];
E = ctx->Intermediate_Hash[4];
for (t = 0; t < 20; t++)
{
temp = SHA1CircularShift(5,A) +
((B & C) | ((~B) & D)) + E + W[t] + K[0];
E = D;
D = C;
C = SHA1CircularShift(30,B);
B = A;
A = temp;
}
for (t = 20; t < 40; t++)
{
temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1];
E = D;
D = C;
C = SHA1CircularShift(30,B);
B = A;
A = temp;
}
for (t = 40; t < 60; t++)
{
temp = SHA1CircularShift(5,A) +
((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
E = D;
D = C;
C = SHA1CircularShift(30,B);
B = A;
A = temp;
}
for (t = 60; t < 80; t++)
{
temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3];
E = D;
D = C;
C = SHA1CircularShift(30,B);
B = A;
A = temp;
}
ctx->Intermediate_Hash[0] += A;
ctx->Intermediate_Hash[1] += B;
ctx->Intermediate_Hash[2] += C;
ctx->Intermediate_Hash[3] += D;
ctx->Intermediate_Hash[4] += E;
ctx->Message_Block_Index = 0;
}
/*
* According to the standard, the message must be padded to an even
* 512 bits. The first padding bit must be a '1'. The last 64
* bits represent the length of the original message. All bits in
* between should be 0. This function will pad the message
* according to those rules by filling the Message_Block array
* accordingly. It will also call the ProcessMessageBlock function
* provided appropriately. When it returns, it can be assumed that
* the message digest has been computed.
*
* @param ctx [in, out] The SHA1 context
*/
static void SHA1PadMessage(SHA1_CTX *ctx)
{
/*
* Check to see if the current message block is too small to hold
* the initial padding bits and length. If so, we will pad the
* block, process it, and then continue padding into a second
* block.
*/
if (ctx->Message_Block_Index > 55)
{
ctx->Message_Block[ctx->Message_Block_Index++] = 0x80;
while(ctx->Message_Block_Index < 64)
{
ctx->Message_Block[ctx->Message_Block_Index++] = 0;
}
SHA1ProcessMessageBlock(ctx);
while (ctx->Message_Block_Index < 56)
{
ctx->Message_Block[ctx->Message_Block_Index++] = 0;
}
}
else
{
ctx->Message_Block[ctx->Message_Block_Index++] = 0x80;
while(ctx->Message_Block_Index < 56)
{
ctx->Message_Block[ctx->Message_Block_Index++] = 0;
}
}
/*
* Store the message length as the last 8 octets
*/
ctx->Message_Block[56] = ctx->Length_High >> 24;
ctx->Message_Block[57] = ctx->Length_High >> 16;
ctx->Message_Block[58] = ctx->Length_High >> 8;
ctx->Message_Block[59] = ctx->Length_High;
ctx->Message_Block[60] = ctx->Length_Low >> 24;
ctx->Message_Block[61] = ctx->Length_Low >> 16;
ctx->Message_Block[62] = ctx->Length_Low >> 8;
ctx->Message_Block[63] = ctx->Length_Low;
SHA1ProcessMessageBlock(ctx);
}
