md5_hash.cpp

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// Code by: B-Con (http://b-con.us)
// Released under the GNU GPL
// MD5 Hash Digest implementation (little endian byte order)
 
 
#include <cstring>
#include <cstdio>
 
#include <md5_hash.h>
 
// DBL_INT_ADD treats two unsigned ints a and b as one 64-bit integer and adds c to it
#define DBL_INT_ADD(a,b,c) if (a > 0xffffffff - c) ++b; a += c;
#define ROTLEFT(a,b) ((a << b) | (a >> (32-b)))
 
#define F(x,y,z) ((x & y) | (~x & z))
#define G(x,y,z) ((x & z) | (y & ~z))
#define H(x,y,z) (x ^ y ^ z)
#define I(x,y,z) (y ^ (x | ~z))
 
#define FF(a,b,c,d,m,s,t) { a += F(b,c,d) + m + t; \
 a = b + ROTLEFT(a,s); }
#define GG(a,b,c,d,m,s,t) { a += G(b,c,d) + m + t; \
 a = b + ROTLEFT(a,s); }
#define HH(a,b,c,d,m,s,t) { a += H(b,c,d) + m + t; \
 a = b + ROTLEFT(a,s); }
#define II(a,b,c,d,m,s,t) { a += I(b,c,d) + m + t; \
 a = b + ROTLEFT(a,s); }
 
 
MD5_HASH::MD5_HASH()
{
 Init();
}
 
 
MD5_HASH::MD5_HASH( const MD5_HASH& aOther )
{
 m_valid = aOther.m_valid;
 m_ctx = aOther.m_ctx;
 memcpy( m_hash, aOther.m_hash, 16 );
}
 
 
MD5_HASH::~MD5_HASH()
{
}
 
MD5_HASH& MD5_HASH::operator=( const MD5_HASH& aOther )
{
 m_valid = aOther.m_valid;
 m_ctx = aOther.m_ctx;
 memcpy( m_hash, aOther.m_hash, 16 );
 
 return *this;
}
 
 
void MD5_HASH::Init()
{
 m_valid = false;
 md5_init( &m_ctx );
 memset( m_hash, 0, 16 );
}
 
 
void MD5_HASH::Hash( uint8_t *data, uint32_t length )
{
 md5_update( &m_ctx, data, length );
}
 
 
void MD5_HASH::Hash( int value )
{
 md5_update( &m_ctx, (uint8_t*) &value, sizeof(int) );
}
 
 
void MD5_HASH::Finalize()
{
 md5_final( &m_ctx, m_hash );
 m_valid = true;
}
 
 
bool MD5_HASH::operator==( const MD5_HASH& aOther ) const
{
 return ( memcmp( m_hash, aOther.m_hash, 16 ) == 0 );
}
 
 
bool MD5_HASH::operator!=( const MD5_HASH& aOther ) const
{
 return ( memcmp( m_hash, aOther.m_hash, 16 ) != 0 );
}
 
 
std::string MD5_HASH::Format( bool aCompactForm )
{
 std::string data;
 
 // Build a hexadecimal string from the 16 bytes of MD5_HASH:
 for( int ii = 0; ii < 16; ++ii )
 {
 char lsb = ( m_hash[ii] & 0x0F ) + '0';
 
 if( lsb > '9' )
 lsb += 'A'-'9';
 
 char msb = ( ( m_hash[ii] >> 4 ) & 0x0F ) + '0';
 
 if( msb > '9' )
 msb += 'A'-'9';
 
 data += msb;
 data += lsb;
 
 if( !aCompactForm )
 data += ' ';
 }
 
 return data;
}
 
 
void MD5_HASH::md5_transform( MD5_CTX* ctx, uint8_t data[] )
{
 uint32_t a,b,c,d,m[16],i,j;
 
 // MD5 specifies big endian byte order, but this implementation assumes a little
 // endian byte order CPU. Reverse all the bytes upon input, and re-reverse them
 // on output (in md5_final()).
 for( i=0, j=0; i < 16; ++i, j += 4 )
 m[i] = (data[j]) + (data[j+1] << 8) + (data[j+2] << 16) + (data[j+3] << 24);
 
 a = ctx->state[0];
 b = ctx->state[1];
 c = ctx->state[2];
 d = ctx->state[3];
 
 FF(a,b,c,d,m[0], 7,0xd76aa478);
 FF(d,a,b,c,m[1], 12,0xe8c7b756);
 FF(c,d,a,b,m[2], 17,0x242070db);
 FF(b,c,d,a,m[3], 22,0xc1bdceee);
 FF(a,b,c,d,m[4], 7,0xf57c0faf);
 FF(d,a,b,c,m[5], 12,0x4787c62a);
 FF(c,d,a,b,m[6], 17,0xa8304613);
 FF(b,c,d,a,m[7], 22,0xfd469501);
 FF(a,b,c,d,m[8], 7,0x698098d8);
 FF(d,a,b,c,m[9], 12,0x8b44f7af);
 FF(c,d,a,b,m[10],17,0xffff5bb1);
 FF(b,c,d,a,m[11],22,0x895cd7be);
 FF(a,b,c,d,m[12], 7,0x6b901122);
 FF(d,a,b,c,m[13],12,0xfd987193);
 FF(c,d,a,b,m[14],17,0xa679438e);
 FF(b,c,d,a,m[15],22,0x49b40821);
 
 GG(a,b,c,d,m[1], 5,0xf61e2562);
 GG(d,a,b,c,m[6], 9,0xc040b340);
 GG(c,d,a,b,m[11],14,0x265e5a51);
 GG(b,c,d,a,m[0], 20,0xe9b6c7aa);
 GG(a,b,c,d,m[5], 5,0xd62f105d);
 GG(d,a,b,c,m[10], 9,0x02441453);
 GG(c,d,a,b,m[15],14,0xd8a1e681);
 GG(b,c,d,a,m[4], 20,0xe7d3fbc8);
 GG(a,b,c,d,m[9], 5,0x21e1cde6);
 GG(d,a,b,c,m[14], 9,0xc33707d6);
 GG(c,d,a,b,m[3], 14,0xf4d50d87);
 GG(b,c,d,a,m[8], 20,0x455a14ed);
 GG(a,b,c,d,m[13], 5,0xa9e3e905);
 GG(d,a,b,c,m[2], 9,0xfcefa3f8);
 GG(c,d,a,b,m[7], 14,0x676f02d9);
 GG(b,c,d,a,m[12],20,0x8d2a4c8a);
 
 HH(a,b,c,d,m[5], 4,0xfffa3942);
 HH(d,a,b,c,m[8], 11,0x8771f681);
 HH(c,d,a,b,m[11],16,0x6d9d6122);
 HH(b,c,d,a,m[14],23,0xfde5380c);
 HH(a,b,c,d,m[1], 4,0xa4beea44);
 HH(d,a,b,c,m[4], 11,0x4bdecfa9);
 HH(c,d,a,b,m[7], 16,0xf6bb4b60);
 HH(b,c,d,a,m[10],23,0xbebfbc70);
 HH(a,b,c,d,m[13], 4,0x289b7ec6);
 HH(d,a,b,c,m[0], 11,0xeaa127fa);
 HH(c,d,a,b,m[3], 16,0xd4ef3085);
 HH(b,c,d,a,m[6], 23,0x04881d05);
 HH(a,b,c,d,m[9], 4,0xd9d4d039);
 HH(d,a,b,c,m[12],11,0xe6db99e5);
 HH(c,d,a,b,m[15],16,0x1fa27cf8);
 HH(b,c,d,a,m[2], 23,0xc4ac5665);
 
 II(a,b,c,d,m[0], 6,0xf4292244);
 II(d,a,b,c,m[7], 10,0x432aff97);
 II(c,d,a,b,m[14],15,0xab9423a7);
 II(b,c,d,a,m[5], 21,0xfc93a039);
 II(a,b,c,d,m[12], 6,0x655b59c3);
 II(d,a,b,c,m[3], 10,0x8f0ccc92);
 II(c,d,a,b,m[10],15,0xffeff47d);
 II(b,c,d,a,m[1], 21,0x85845dd1);
 II(a,b,c,d,m[8], 6,0x6fa87e4f);
 II(d,a,b,c,m[15],10,0xfe2ce6e0);
 II(c,d,a,b,m[6], 15,0xa3014314);
 II(b,c,d,a,m[13],21,0x4e0811a1);
 II(a,b,c,d,m[4], 6,0xf7537e82);
 II(d,a,b,c,m[11],10,0xbd3af235);
 II(c,d,a,b,m[2], 15,0x2ad7d2bb);
 II(b,c,d,a,m[9], 21,0xeb86d391);
 
 ctx->state[0] += a;
 ctx->state[1] += b;
 ctx->state[2] += c;
 ctx->state[3] += d;
}
 
 
void MD5_HASH::md5_init( MD5_CTX* ctx )
{
 memset( ctx->data, 0, 64 );
 ctx->datalen = 0;
 ctx->bitlen[0] = 0;
 ctx->bitlen[1] = 0;
 ctx->state[0] = 0x67452301;
 ctx->state[1] = 0xEFCDAB89;
 ctx->state[2] = 0x98BADCFE;
 ctx->state[3] = 0x10325476;
}
 
 
void MD5_HASH::md5_update( MD5_CTX* ctx, uint8_t data[], uint32_t len )
{
 for( uint32_t i = 0; i < len; ++i )
 {
 ctx->data[ctx->datalen] = data[i];
 ctx->datalen++;
 
 if( ctx->datalen == 64 )
 {
 md5_transform( ctx,ctx->data );
 DBL_INT_ADD( ctx->bitlen[0], ctx->bitlen[1], 512 );
 ctx->datalen = 0;
 }
 }
}
 
 
void MD5_HASH::md5_final( MD5_CTX *ctx, uint8_t hash[] )
{
 uint32_t i = ctx->datalen;
 
 // Pad whatever data is left in the buffer.
 if( ctx->datalen < 56 )
 {
 ctx->data[i++] = 0x80;
 
 while( i < 56 )
 ctx->data[i++] = 0x00;
 }
 else if (ctx->datalen >= 56)
 {
 ctx->data[i++] = 0x80;
 
 while( i < 64 )
 ctx->data[i++] = 0x00;
 
 md5_transform( ctx, ctx->data );
 memset( ctx->data, 0, 56 );
 }
 
 // Append to the padding the total message's length in bits and transform.
 DBL_INT_ADD(ctx->bitlen[0],ctx->bitlen[1],8 * ctx->datalen);
 ctx->data[56] = static_cast<uint8_t>( ctx->bitlen[0] );
 ctx->data[57] = static_cast<uint8_t>(ctx->bitlen[0] >> 8 );
 ctx->data[58] = static_cast<uint8_t>(ctx->bitlen[0] >> 16 );
 ctx->data[59] = static_cast<uint8_t>(ctx->bitlen[0] >> 24 );
 ctx->data[60] = static_cast<uint8_t>(ctx->bitlen[1] );
 ctx->data[61] = static_cast<uint8_t>(ctx->bitlen[1] >> 8 );
 ctx->data[62] = static_cast<uint8_t>(ctx->bitlen[1] >> 16 );
 ctx->data[63] = static_cast<uint8_t>(ctx->bitlen[1] >> 24 );
 md5_transform(ctx,ctx->data);
 
 // Since this implementation uses little endian byte ordering and MD uses big endian,
 // reverse all the bytes when copying the final state to the output hash.
 for( i=0; i < 4; ++i )
 {
 hash[i] = (ctx->state[0] >> (i*8)) & 0x000000ff;
 hash[i+4] = (ctx->state[1] >> (i*8)) & 0x000000ff;
 hash[i+8] = (ctx->state[2] >> (i*8)) & 0x000000ff;
 hash[i+12] = (ctx->state[3] >> (i*8)) & 0x000000ff;
 }
}