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/* sha1.cpp
Copyright (c) 2005 Michael D. Leonhard
http://tamale.net/
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cassert>
#include "sha1.h"
// print out memory in hexadecimal
void SHA1::hexPrinter( unsigned char* c, int l )
{
assert( c );
assert( l > 0 );
while( l > 0 )
{
printf( " %02x", *c );
l--;
c++;
}
}
// circular left bit rotation. MSB wraps around to LSB
Uint32 SHA1::lrot( Uint32 x, int bits )
{
return (x<<bits) | (x>>(32 - bits));
};
// Save a 32-bit unsigned integer to memory, in big-endian order
void SHA1::storeBigEndianUint32( unsigned char* byte, Uint32 num )
{
assert( byte );
byte[0] = (unsigned char)(num>>24);
byte[1] = (unsigned char)(num>>16);
byte[2] = (unsigned char)(num>>8);
byte[3] = (unsigned char)num;
}
// Constructor *******************************************************
SHA1::SHA1()
{
// make sure that the data type is the right size
assert( sizeof( Uint32 ) * 5 == 20 );
}
// Destructor ********************************************************
SHA1::~SHA1()
{
// erase data
H0 = H1 = H2 = H3 = H4 = 0;
for( int c = 0; c < 64; c++ ) bytes[c] = 0;
unprocessedBytes = size = 0;
}
// process ***********************************************************
void SHA1::process()
{
assert( unprocessedBytes == 64 );
//printf( "process: " ); hexPrinter( bytes, 64 ); printf( "\n" );
int t;
Uint32 a, b, c, d, e, K, f, W[80];
// starting values
a = H0;
b = H1;
c = H2;
d = H3;
e = H4;
// copy and expand the message block
for( t = 0; t < 16; t++ ) W[t] = (bytes[t*4] << 24)
+(bytes[t*4 + 1] << 16)
+(bytes[t*4 + 2] << 8)
+ bytes[t*4 + 3];
for(; t< 80; t++ ) W[t] = lrot( W[t-3]^W[t-8]^W[t-14]^W[t-16], 1 );
/* main loop */
Uint32 temp;
for( t = 0; t < 80; t++ )
{
if( t < 20 ) {
K = 0x5a827999;
f = (b & c) | ((b ^ 0xFFFFFFFF) & d);//TODO: try using ~
} else if( t < 40 ) {
K = 0x6ed9eba1;
f = b ^ c ^ d;
} else if( t < 60 ) {
K = 0x8f1bbcdc;
f = (b & c) | (b & d) | (c & d);
} else {
K = 0xca62c1d6;
f = b ^ c ^ d;
}
temp = lrot(a,5) + f + e + W[t] + K;
e = d;
d = c;
c = lrot(b,30);
b = a;
a = temp;
//printf( "t=%d %08x %08x %08x %08x %08x\n",t,a,b,c,d,e );
}
/* add variables */
H0 += a;
H1 += b;
H2 += c;
H3 += d;
H4 += e;
//printf( "Current: %08x %08x %08x %08x %08x\n",H0,H1,H2,H3,H4 );
/* all bytes have been processed */
unprocessedBytes = 0;
}
// addBytes **********************************************************
void SHA1::addBytes( const char* data, int num )
{
assert( data );
assert( num >= 0 );
// add these bytes to the running total
size += num;
// repeat until all data is processed
while( num > 0 )
{
// number of bytes required to complete block
int needed = 64 - unprocessedBytes;
assert( needed > 0 );
// number of bytes to copy (use smaller of two)
int toCopy = (num < needed) ? num : needed;
// Copy the bytes
memcpy( bytes + unprocessedBytes, data, toCopy );
// Bytes have been copied
num -= toCopy;
data += toCopy;
unprocessedBytes += toCopy;
// there is a full block
if( unprocessedBytes == 64 ) process();
}
}
// digest ************************************************************
unsigned char* SHA1::getDigest()
{
// save the message size
Uint32 totalBitsL = size << 3;
Uint32 totalBitsH = size >> 29;
// add 0x80 to the message
addBytes( "\x80", 1 );
unsigned char footer[64] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
// block has no room for 8-byte filesize, so finish it
if( unprocessedBytes > 56 )
addBytes( (char*)footer, 64 - unprocessedBytes);
assert( unprocessedBytes <= 56 );
// how many zeros do we need
int neededZeros = 56 - unprocessedBytes;
// store file size (in bits) in big-endian format
storeBigEndianUint32( footer + neededZeros , totalBitsH );
storeBigEndianUint32( footer + neededZeros + 4, totalBitsL );
// finish the final block
addBytes( (char*)footer, neededZeros + 8 );
// allocate memory for the digest bytes
unsigned char* digest = (unsigned char*)malloc( 20 );
// copy the digest bytes
storeBigEndianUint32( digest, H0 );
storeBigEndianUint32( digest + 4, H1 );
storeBigEndianUint32( digest + 8, H2 );
storeBigEndianUint32( digest + 12, H3 );
storeBigEndianUint32( digest + 16, H4 );
// return the digest
return digest;
}
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