libcruft-util/hash/md5.cpp

293 lines
7.3 KiB
C++

/*
* This file is part of libgim.
*
* libgim is free software: you can redistribute it and/or modify it under the
* terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* libgim 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 General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with libgim. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright 2013 Danny Robson <danny@nerdcruft.net>
*/
#include "md5.hpp"
#include "bitwise.hpp"
#include <cstring>
using util::hash::MD5;
// Per-round mixing functions
static inline uint32_t
F (uint32_t x, uint32_t y, uint32_t z)
//{ return (x & y) | (~x & z); }
{ return z ^ (x & (y ^ z)); }
static inline uint32_t
G (uint32_t x, uint32_t y, uint32_t z)
//{ return (x & z) | (y & ~z); }
{ return F (z, x, y); }
static inline uint32_t
H (uint32_t x, uint32_t y, uint32_t z)
{ return x ^ y ^ z; }
static inline uint32_t
I (uint32_t x, uint32_t y, uint32_t z)
{ return y ^ (x | ~z); }
// Mixing constants for all rounds. They are defined as 'abs(sin(i)) * max_uint32', but we use the
// literals to avoid any stupid maths issues during compilation.
const std::array<uint32_t, 65> T = { {
0x00000000,
// Round 1
0xd76aa478u, 0xe8c7b756u, 0x242070dbu, 0xc1bdceeeu,
0xf57c0fafu, 0x4787c62au, 0xa8304613u, 0xfd469501u,
0x698098d8u, 0x8b44f7afu, 0xffff5bb1u, 0x895cd7beu,
0x6b901122u, 0xfd987193u, 0xa679438eu, 0x49b40821u,
// Round 2
0xf61e2562u, 0xc040b340u, 0x265e5a51u, 0xe9b6c7aau,
0xd62f105du, 0x02441453u, 0xd8a1e681u, 0xe7d3fbc8u,
0x21e1cde6u, 0xc33707d6u, 0xf4d50d87u, 0x455a14edu,
0xa9e3e905u, 0xfcefa3f8u, 0x676f02d9u, 0x8d2a4c8au,
// Round 3
0xfffa3942u, 0x8771f681u, 0x6d9d6122u, 0xfde5380cu,
0xa4beea44u, 0x4bdecfa9u, 0xf6bb4b60u, 0xbebfbc70u,
0x289b7ec6u, 0xeaa127fau, 0xd4ef3085u, 0x04881d05u,
0xd9d4d039u, 0xe6db99e5u, 0x1fa27cf8u, 0xc4ac5665u,
// Round 4
0xf4292244u, 0x432aff97u, 0xab9423a7u, 0xfc93a039u,
0x655b59c3u, 0x8f0ccc92u, 0xffeff47du, 0x85845dd1u,
0x6fa87e4fu, 0xfe2ce6e0u, 0xa3014314u, 0x4e0811a1u,
0xf7537e82u, 0xbd3af235u, 0x2ad7d2bbu, 0xeb86d391u
} };
static const uint32_t DEFAULT_A = 0x67452301;
static const uint32_t DEFAULT_B = 0xefcdab89;
static const uint32_t DEFAULT_C = 0x98badcfe;
static const uint32_t DEFAULT_D = 0x10325476;
MD5::MD5()
{
reset ();
}
void
MD5::reset (void) {
m_total = 0;
ABCD[0] = DEFAULT_A;
ABCD[1] = DEFAULT_B;
ABCD[2] = DEFAULT_C;
ABCD[3] = DEFAULT_D;
}
void
MD5::update (const void *data, size_t len)
{ MD5::update (static_cast<const uint8_t*> (data), len); }
void
MD5::update (const uint8_t *data, size_t size) {
size_t offset = m_total % sizeof (Xb);
size_t remain = sizeof (Xb) - offset;
if (size > remain) {
memcpy (Xb + offset, data, remain);
transform ();
m_total += remain;
size -= remain;
data += remain;
while (size >= sizeof (Xb)) {
memcpy (Xb, data, sizeof (Xb));
transform ();
m_total += sizeof (Xb);
size -= sizeof (Xb);
data += sizeof (Xb);
}
offset = 0;
}
memcpy (Xb + offset, data, size);
m_total += size;
}
MD5::digest_t
MD5::digest (void) {
finish ();
static_assert (sizeof (ABCD) == sizeof (digest_t),
"Hash state must be the same size as the final digest");
digest_t d;
memcpy (d.data (), ABCD.data (), sizeof (ABCD));
return d;
}
void
MD5::finish (void) {
uint64_t bits = m_total * 8;
{
// Pad with the mandatory 1 bit
size_t offset = m_total % sizeof (Xb);
Xb[offset] = 0x80;
}
{
// Pad the remainder with 0's, until 56 bytes
size_t offset = (m_total + 1) % sizeof (Xb);
size_t remain = (56 - offset % sizeof (Xb)) % sizeof (Xb);
if (offset > 56) {
memset (Xb + offset, 0, sizeof (Xb) - offset);
transform ();
remain -= sizeof (Xb) - offset;
offset = 0;
}
memset (Xb + offset, 0, remain);
// Put in the length (in bits) least significant first
for (size_t i = 0; i < sizeof (bits); ++i) {
Xb[56 + i] = bits & 0xFF;
bits >>= 8;
}
transform ();
}
}
void
MD5::transform (void) {
uint32_t A = ABCD[0],
B = ABCD[1],
C = ABCD[2],
D = ABCD[3];
#define ROUNDx(a,b,c,d,k,s,i,f) do { \
(a) += (f)((b), (c), (d)) + X[k] + T[i]; \
(a) = rotatel ((a), (s)); \
(a) += (b); \
} while (0)
// Round 1
ROUNDx(A,B,C,D, 0, 7, 1, F);
ROUNDx(D,A,B,C, 1, 12, 2, F);
ROUNDx(C,D,A,B, 2, 17, 3, F);
ROUNDx(B,C,D,A, 3, 22, 4, F);
ROUNDx(A,B,C,D, 4, 7, 5, F);
ROUNDx(D,A,B,C, 5, 12, 6, F);
ROUNDx(C,D,A,B, 6, 17, 7, F);
ROUNDx(B,C,D,A, 7, 22, 8, F);
ROUNDx(A,B,C,D, 8, 7, 9, F);
ROUNDx(D,A,B,C, 9, 12, 10, F);
ROUNDx(C,D,A,B, 10, 17, 11, F);
ROUNDx(B,C,D,A, 11, 22, 12, F);
ROUNDx(A,B,C,D, 12, 7, 13, F);
ROUNDx(D,A,B,C, 13, 12, 14, F);
ROUNDx(C,D,A,B, 14, 17, 15, F);
ROUNDx(B,C,D,A, 15, 22, 16, F);
// Round 2
ROUNDx(A,B,C,D, 1, 5, 17, G);
ROUNDx(D,A,B,C, 6, 9, 18, G);
ROUNDx(C,D,A,B, 11, 14, 19, G);
ROUNDx(B,C,D,A, 0, 20, 20, G);
ROUNDx(A,B,C,D, 5, 5, 21, G);
ROUNDx(D,A,B,C, 10, 9, 22, G);
ROUNDx(C,D,A,B, 15, 14, 23, G);
ROUNDx(B,C,D,A, 4, 20, 24, G);
ROUNDx(A,B,C,D, 9, 5, 25, G);
ROUNDx(D,A,B,C, 14, 9, 26, G);
ROUNDx(C,D,A,B, 3, 14, 27, G);
ROUNDx(B,C,D,A, 8, 20, 28, G);
ROUNDx(A,B,C,D, 13, 5, 29, G);
ROUNDx(D,A,B,C, 2, 9, 30, G);
ROUNDx(C,D,A,B, 7, 14, 31, G);
ROUNDx(B,C,D,A, 12, 20, 32, G);
// Round 3
ROUNDx(A,B,C,D, 5, 4, 33, H);
ROUNDx(D,A,B,C, 8, 11, 34, H);
ROUNDx(C,D,A,B, 11, 16, 35, H);
ROUNDx(B,C,D,A, 14, 23, 36, H);
ROUNDx(A,B,C,D, 1, 4, 37, H);
ROUNDx(D,A,B,C, 4, 11, 38, H);
ROUNDx(C,D,A,B, 7, 16, 39, H);
ROUNDx(B,C,D,A, 10, 23, 40, H);
ROUNDx(A,B,C,D, 13, 4, 41, H);
ROUNDx(D,A,B,C, 0, 11, 42, H);
ROUNDx(C,D,A,B, 3, 16, 43, H);
ROUNDx(B,C,D,A, 6, 23, 44, H);
ROUNDx(A,B,C,D, 9, 4, 45, H);
ROUNDx(D,A,B,C, 12, 11, 46, H);
ROUNDx(C,D,A,B, 15, 16, 47, H);
ROUNDx(B,C,D,A, 2, 23, 48, H);
// Round 4
ROUNDx(A,B,C,D, 0, 6, 49, I);
ROUNDx(D,A,B,C, 7, 10, 50, I);
ROUNDx(C,D,A,B, 14, 15, 51, I);
ROUNDx(B,C,D,A, 5, 21, 52, I);
ROUNDx(A,B,C,D, 12, 6, 53, I);
ROUNDx(D,A,B,C, 3, 10, 54, I);
ROUNDx(C,D,A,B, 10, 15, 55, I);
ROUNDx(B,C,D,A, 1, 21, 56, I);
ROUNDx(A,B,C,D, 8, 6, 57, I);
ROUNDx(D,A,B,C, 15, 10, 58, I);
ROUNDx(C,D,A,B, 6, 15, 59, I);
ROUNDx(B,C,D,A, 13, 21, 60, I);
ROUNDx(A,B,C,D, 4, 6, 61, I);
ROUNDx(D,A,B,C, 11, 10, 62, I);
ROUNDx(C,D,A,B, 2, 15, 63, I);
ROUNDx(B,C,D,A, 9, 21, 64, I);
ABCD[0] += A;
ABCD[1] += B;
ABCD[2] += C;
ABCD[3] += D;
}