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mpv/libvo/md5sum.c
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/* ========================================================================== **
*
* MD5.c
*
* Copyright:
* Copyright (C) 2003, 2004 by Christopher R. Hertel
*
* Email: crh@ubiqx.mn.org
*
* Modified for use with MPlayer, detailed CVS changelog at
* http://www.mplayerhq.hu/cgi-bin/cvsweb.cgi/main/
* $Id$
*
* -------------------------------------------------------------------------- **
*
* Description:
* Implements the MD5 hash algorithm, as described in RFC 1321.
*
* -------------------------------------------------------------------------- **
*
* License:
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* -------------------------------------------------------------------------- **
*
* Notes:
*
* None of this will make any sense unless you're studying RFC 1321 as you
* read the code.
*
* MD5 is described in RFC 1321.
* The MD*4* algorithm is described in RFC 1320 (that's 1321 - 1).
* MD5 is very similar to MD4, but not quite similar enough to justify
* putting the two into a single module. Besides, I wanted to add a few
* extra functions to this one to expand its usability.
*
* There are three primary motivations for this particular implementation.
* 1) Programmer's pride. I wanted to be able to say I'd done it, and I
* wanted to learn from the experience.
* 2) Portability. I wanted an implementation that I knew to be portable
* to a reasonable number platforms. In particular, the algorithm is
* designed with little-endian platforms in mind, but I wanted an
* endian-agnostic implementation.
* 3) Compactness. While not an overriding goal, I thought it worth-while
* to see if I could reduce the overall size of the result. This is in
* keeping with my hopes that this library will be suitable for use in
* some embedded environments.
* Beyond that, cleanliness and clarity are always worth pursuing.
*
* As mentioned above, the code really only makes sense if you are familiar
* with the MD5 algorithm or are using RFC 1321 as a guide. This code is
* quirky, however, so you'll want to be reading carefully.
*
* Yeah...most of the comments are cut-and-paste from my MD4 implementation.
*
* -------------------------------------------------------------------------- **
*
* References:
* IETF RFC 1321: The MD5 Message-Digest Algorithm
* Ron Rivest. IETF, April, 1992
*
* ========================================================================== **
*/
/* #include "MD5.h" Line of original code */
#include "md5sum.h" /* Added this line */
/* -------------------------------------------------------------------------- **
* Static Constants:
*
* K[][] - In round one, the values of k (which are used to index
* particular four-byte sequences in the input) are simply
* sequential. In later rounds, however, they are a bit more
* varied. Rather than calculate the values of k (which may
* or may not be possible--I haven't though about it) the
* values are stored in this array.
*
* S[][] - In each round there is a left rotate operation performed as
* part of the 16 permutations. The number of bits varies in
* a repeating patter. This array keeps track of the patterns
* used in each round.
*
* T[][] - There are four rounds of 16 permutations for a total of 64.
* In each of these 64 permutation operations, a different
* constant value is added to the mix. The constants are
* based on the sine function...read RFC 1321 for more detail.
* In any case, the correct constants are stored in the T[][]
* array. They're divided up into four groups of 16.
*/
static const uint8_t K[3][16] =
{
/* Round 1: skipped (since it is simply sequential). */
{ 1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12 }, /* R2 */
{ 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2 }, /* R3 */
{ 0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9 } /* R4 */
};
static const uint8_t S[4][4] =
{
{ 7, 12, 17, 22 }, /* Round 1 */
{ 5, 9, 14, 20 }, /* Round 2 */
{ 4, 11, 16, 23 }, /* Round 3 */
{ 6, 10, 15, 21 } /* Round 4 */
};
static const uint32_t T[4][16] =
{
{ 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, /* Round 1 */
0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821 },
{ 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, /* Round 2 */
0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a },
{ 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, /* Round 3 */
0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05,
0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665 },
{ 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, /* Round 4 */
0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 },
};
/* -------------------------------------------------------------------------- **
* Macros:
* md5F(), md5G(), md5H(), and md5I() are described in RFC 1321.
* All of these operations are bitwise, and so not impacted by endian-ness.
*
* GetLongByte()
* Extract one byte from a (32-bit) longword. A value of 0 for <idx>
* indicates the lowest order byte, while 3 indicates the highest order
* byte.
*
*/
#define md5F( X, Y, Z ) ( ((X) & (Y)) | ((~(X)) & (Z)) )
#define md5G( X, Y, Z ) ( ((X) & (Z)) | ((Y) & (~(Z))) )
#define md5H( X, Y, Z ) ( (X) ^ (Y) ^ (Z) )
#define md5I( X, Y, Z ) ( (Y) ^ ((X) | (~(Z))) )
#define GetLongByte( L, idx ) ((uchar)(( L >> (((idx) & 0x03) << 3) ) & 0xFF))
/* -------------------------------------------------------------------------- **
* Static Functions:
*/
static void Permute( uint32_t ABCD[4], const uchar block[64] )
/* ------------------------------------------------------------------------ **
* Permute the ABCD "registers" using the 64-byte <block> as a driver.
*
* Input: ABCD - Pointer to an array of four unsigned longwords.
* block - An array of bytes, 64 bytes in size.
*
* Output: none.
*
* Notes: The MD5 algorithm operates on a set of four longwords stored
* (conceptually) in four "registers". It is easy to imagine a
* simple MD4/5 chip that would operate this way. In any case,
* the mangling of the contents of those registers is driven by
* the input message. The message is chopped and finally padded
* into 64-byte chunks and each chunk is used to manipulate the
* contents of the registers.
*
* The MD5 Algorithm calls for padding the input to ensure that
* it is a multiple of 64 bytes in length. The last 16 bytes
* of the padding space are used to store the message length
* (the length of the original message, before padding, expressed
* in terms of bits). If there is not enough room for 16 bytes
* worth of bitcount (eg., if the original message was 122 bytes
* long) then the block is padded to the end with zeros and
* passed to this function. Then *another* block is filled with
* zeros except for the last 16 bytes which contain the length.
*
* Oh... and the algorithm requires that there be at least one
* padding byte. The first padding byte has a value of 0x80,
* and any others are 0x00.
*
* ------------------------------------------------------------------------ **
*/
{
int round;
int i, j;
uint8_t s;
uint32_t a, b, c, d;
uint32_t KeepABCD[4];
uint32_t X[16];
/* Store the current ABCD values for later re-use.
*/
for( i = 0; i < 4; i++ )
KeepABCD[i] = ABCD[i];
/* Convert the input block into an array of unsigned longs, taking care
* to read the block in Little Endian order (the algorithm assumes this).
* The uint32_t values are then handled in host order.
*/
for( i = 0, j = 0; i < 16; i++ )
{
X[i] = (uint32_t)block[j++];
X[i] |= ((uint32_t)block[j++] << 8);
X[i] |= ((uint32_t)block[j++] << 16);
X[i] |= ((uint32_t)block[j++] << 24);
}
/* This loop performs the four rounds of permutations.
* The rounds are each very similar. The differences are in three areas:
* - The function (F, G, H, or I) used to perform bitwise permutations
* on the registers,
* - The order in which values from X[] are chosen.
* - Changes to the number of bits by which the registers are rotated.
* This implementation uses a switch statement to deal with some of the
* differences between rounds. Other differences are handled by storing
* values in arrays and using the round number to select the correct set
* of values.
*
* (My implementation appears to be a poor compromise between speed, size,
* and clarity. Ugh. [crh])
*/
for( round = 0; round < 4; round++ )
{
for( i = 0; i < 16; i++ )
{
j = (4 - (i % 4)) & 0x3; /* <j> handles the rotation of ABCD. */
s = S[round][i%4]; /* <s> is the bit shift for this iteration. */
b = ABCD[(j+1) & 0x3]; /* Copy the b,c,d values per ABCD rotation. */
c = ABCD[(j+2) & 0x3]; /* This isn't really necessary, it just looks */
d = ABCD[(j+3) & 0x3]; /* clean & will hopefully be optimized away. */
/* The actual perumation function.
* This is broken out to minimize the code within the switch().
*/
switch( round )
{
case 0:
/* round 1 */
a = md5F( b, c, d ) + X[i];
break;
case 1:
/* round 2 */
a = md5G( b, c, d ) + X[ K[0][i] ];
break;
case 2:
/* round 3 */
a = md5H( b, c, d ) + X[ K[1][i] ];
break;
default:
/* round 4 */
a = md5I( b, c, d ) + X[ K[2][i] ];
break;
}
a = 0xFFFFFFFF & ( ABCD[j] + a + T[round][i] );
ABCD[j] = b + (0xFFFFFFFF & (( a << s ) | ( a >> (32 - s) )));
}
}
/* Use the stored original A, B, C, D values to perform
* one last convolution.
*/
for( i = 0; i < 4; i++ )
ABCD[i] = 0xFFFFFFFF & ( ABCD[i] + KeepABCD[i] );
} /* Permute */
/* -------------------------------------------------------------------------- **
* Functions:
*/
auth_md5Ctx *auth_md5InitCtx( auth_md5Ctx *ctx )
/* ------------------------------------------------------------------------ **
* Initialize an MD5 context.
*
* Input: ctx - A pointer to the MD5 context structure to be initialized.
* Contexts are typically created thusly:
* ctx = (auth_md5Ctx *)malloc( sizeof(auth_md5Ctx) );
*
* Output: A pointer to the initialized context (same as <ctx>).
*
* Notes: The purpose of the context is to make it possible to generate
* an MD5 Message Digest in stages, rather than having to pass a
* single large block to a single MD5 function. The context
* structure keeps track of various bits of state information.
*
* Once the context is initialized, the blocks of message data
* are passed to the <auth_md5SumCtx()> function. Once the
* final bit of data has been handed to <auth_md5SumCtx()> the
* context can be closed out by calling <auth_md5CloseCtx()>,
* which also calculates the final MD5 result.
*
* Don't forget to free an allocated context structure when
* you've finished using it.
*
* See Also: <auth_md5SumCtx()>, <auth_md5CloseCtx()>
*
* ------------------------------------------------------------------------ **
*/
{
ctx->len = 0;
ctx->b_used = 0;
ctx->ABCD[0] = 0x67452301; /* The array ABCD[] contains the four 4-byte */
ctx->ABCD[1] = 0xefcdab89; /* "registers" that are manipulated to */
ctx->ABCD[2] = 0x98badcfe; /* produce the MD5 digest. The input acts */
ctx->ABCD[3] = 0x10325476; /* upon the registers, not the other way */
/* 'round. The initial values are those */
/* given in RFC 1321 (pg. 4). Note, however, that RFC 1321 */
/* provides these values as bytes, not as longwords, and the */
/* bytes are arranged in little-endian order as if they were */
/* the bytes of (little endian) 32-bit ints. That's */
/* confusing as all getout (to me, anyway). The values given */
/* here are provided as 32-bit values in C language format, */
/* so they are endian-agnostic. */
return( ctx );
} /* auth_md5InitCtx */
auth_md5Ctx *auth_md5SumCtx( auth_md5Ctx *ctx,
const uchar *src,
const int len )
/* ------------------------------------------------------------------------ **
* Build an MD5 Message Digest within the given context.
*
* Input: ctx - Pointer to the context in which the MD5 sum is being
* built.
* src - A chunk of source data. This will be used to drive
* the MD5 algorithm.
* len - The number of bytes in <src>.
*
* Output: A pointer to the updated context (same as <ctx>).
*
* See Also: <auth_md5InitCtx()>, <auth_md5CloseCtx()>, <auth_md5Sum()>
*
* ------------------------------------------------------------------------ **
*/
{
int i;
/* Add the new block's length to the total length.
*/
ctx->len += (uint32_t)len;
/* Copy the new block's data into the context block.
* Call the Permute() function whenever the context block is full.
*/
for( i = 0; i < len; i++ )
{
ctx->block[ ctx->b_used ] = src[i];
(ctx->b_used)++;
if( 64 == ctx->b_used )
{
Permute( ctx->ABCD, ctx->block );
ctx->b_used = 0;
}
}
/* Return the updated context.
*/
return( ctx );
} /* auth_md5SumCtx */
auth_md5Ctx *auth_md5CloseCtx( auth_md5Ctx *ctx, uchar *dst )
/* ------------------------------------------------------------------------ **
* Close an MD5 Message Digest context and generate the final MD5 sum.
*
* Input: ctx - Pointer to the context in which the MD5 sum is being
* built.
* dst - A pointer to at least 16 bytes of memory, which will
* receive the finished MD5 sum.
*
* Output: A pointer to the closed context (same as <ctx>).
* You might use this to free a malloc'd context structure. :)
*
* Notes: The context (<ctx>) is returned in an undefined state.
* It must be re-initialized before re-use.
*
* See Also: <auth_md5InitCtx()>, <auth_md5SumCtx()>
*
* ------------------------------------------------------------------------ **
*/
{
int i;
uint32_t l;
/* Add the required 0x80 padding initiator byte.
* The auth_md5SumCtx() function always permutes and resets the context
* block when it gets full, so we know that there must be at least one
* free byte in the context block.
*/
ctx->block[ctx->b_used] = 0x80;
(ctx->b_used)++;
/* Zero out any remaining free bytes in the context block.
*/
for( i = ctx->b_used; i < 64; i++ )
ctx->block[i] = 0;
/* We need 8 bytes to store the length field.
* If we don't have 8, call Permute() and reset the context block.
*/
if( 56 < ctx->b_used )
{
Permute( ctx->ABCD, ctx->block );
for( i = 0; i < 64; i++ )
ctx->block[i] = 0;
}
/* Add the total length and perform the final perumation.
* Note: The 60'th byte is read from the *original* <ctx->len> value
* and shifted to the correct position. This neatly avoids
* any MAXINT numeric overflow issues.
*/
l = ctx->len << 3;
for( i = 0; i < 4; i++ )
ctx->block[56+i] |= GetLongByte( l, i );
ctx->block[60] = ((GetLongByte( ctx->len, 3 ) & 0xE0) >> 5); /* See Above! */
Permute( ctx->ABCD, ctx->block );
/* Now copy the result into the output buffer and we're done.
*/
for( i = 0; i < 4; i++ )
{
dst[ 0+i] = GetLongByte( ctx->ABCD[0], i );
dst[ 4+i] = GetLongByte( ctx->ABCD[1], i );
dst[ 8+i] = GetLongByte( ctx->ABCD[2], i );
dst[12+i] = GetLongByte( ctx->ABCD[3], i );
}
/* Return the context.
* This is done for compatibility with the other auth_md5*Ctx() functions.
*/
return( ctx );
} /* auth_md5CloseCtx */
uchar *auth_md5Sum( uchar *dst, const uchar *src, const int len )
/* ------------------------------------------------------------------------ **
* Compute an MD5 message digest.
*
* Input: dst - Destination buffer into which the result will be written.
* Must be 16 bytes, minimum.
* src - Source data block to be MD5'd.
* len - The length, in bytes, of the source block.
* (Note that the length is given in bytes, not bits.)
*
* Output: A pointer to <dst>, which will contain the calculated 16-byte
* MD5 message digest.
*
* Notes: This function is a shortcut. It takes a single input block.
* For more drawn-out operations, see <auth_md5InitCtx()>.
*
* This function is interface-compatible with the
* <auth_md4Sum()> function in the MD4 module.
*
* The MD5 algorithm is designed to work on data with an
* arbitrary *bit* length. Most implementations, this one
* included, handle the input data in byte-sized chunks.
*
* The MD5 algorithm does much of its work using four-byte
* words, and so can be tuned for speed based on the endian-ness
* of the host. This implementation is intended to be
* endian-neutral, which may make it a teeny bit slower than
* others. ...maybe.
*
* See Also: <auth_md5InitCtx()>
*
* ------------------------------------------------------------------------ **
*/
{
auth_md5Ctx ctx[1];
(void)auth_md5InitCtx( ctx ); /* Open a context. */
(void)auth_md5SumCtx( ctx, src, len ); /* Pass only one block. */
(void)auth_md5CloseCtx( ctx, dst ); /* Close the context. */
return( dst ); /* Makes life easy. */
} /* auth_md5Sum */
/* ========================================================================== */
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