PolarSSL is now part of ARM Official announcement and rebranded as mbed TLS.

MD5 source code

MD5

The source code for the MD5 algorithm. This source code is part of the mbed TLS library and represents the most current version in the trunk of the library.
Download mbed TLS

MD5 is a cryptographic hash function that is specified in RFC 1321 and produces a 128-bit hash value. The full algorithm of MD5 is further explained in MD5 algorithm (Wikipedia).

Warning: MD5 is not considered secure anymore. For secure software, please use SHA-256 or SHA-512 instead.

The code only has a single dependency on config.h in the md5.c source code file. You can remove this inclusion or just create a simple header file to define one or more of the configuration options that the MD5 source code has.

Full documentation on the MD5 source code can be found in the API documentation for the MD5 module.

You can also download it as part of the latest release of mbed TLS.

Header - md5.h

The md5.h header can also be found in the trunk on: md5.h.

/**
 * \file md5.h
 *
 * \brief MD5 message digest algorithm (hash function)
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
#ifndef MBEDTLS_MD5_H
#define MBEDTLS_MD5_H

#if !defined(MBEDTLS_CONFIG_FILE)
#include "config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#include <stddef.h>
#include <stdint.h>

#if !defined(MBEDTLS_MD5_ALT)
// Regular implementation
//

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief          MD5 context structure
 */
typedef struct
{
    uint32_t total[2];          /*!< number of bytes processed  */
    uint32_t state[4];          /*!< intermediate digest state  */
    unsigned char buffer[64];   /*!< data block being processed */
}
mbedtls_md5_context;

/**
 * \brief          Initialize MD5 context
 *
 * \param ctx      MD5 context to be initialized
 */
void mbedtls_md5_init( mbedtls_md5_context *ctx );

/**
 * \brief          Clear MD5 context
 *
 * \param ctx      MD5 context to be cleared
 */
void mbedtls_md5_free( mbedtls_md5_context *ctx );

/**
 * \brief          Clone (the state of) an MD5 context
 *
 * \param dst      The destination context
 * \param src      The context to be cloned
 */
void mbedtls_md5_clone( mbedtls_md5_context *dst,
                        const mbedtls_md5_context *src );

/**
 * \brief          MD5 context setup
 *
 * \param ctx      context to be initialized
 */
void mbedtls_md5_starts( mbedtls_md5_context *ctx );

/**
 * \brief          MD5 process buffer
 *
 * \param ctx      MD5 context
 * \param input    buffer holding the  data
 * \param ilen     length of the input data
 */
void mbedtls_md5_update( mbedtls_md5_context *ctx, const unsigned char *input, size_t ilen );

/**
 * \brief          MD5 final digest
 *
 * \param ctx      MD5 context
 * \param output   MD5 checksum result
 */
void mbedtls_md5_finish( mbedtls_md5_context *ctx, unsigned char output[16] );

/* Internal use */
void mbedtls_md5_process( mbedtls_md5_context *ctx, const unsigned char data[64] );

#ifdef __cplusplus
}
#endif

#else  /* MBEDTLS_MD5_ALT */
#include "md5_alt.h"
#endif /* MBEDTLS_MD5_ALT */

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief          Output = MD5( input buffer )
 *
 * \param input    buffer holding the  data
 * \param ilen     length of the input data
 * \param output   MD5 checksum result
 */
void mbedtls_md5( const unsigned char *input, size_t ilen, unsigned char output[16] );

/**
 * \brief          Checkup routine
 *
 * \return         0 if successful, or 1 if the test failed
 */
int mbedtls_md5_self_test( int verbose );

#ifdef __cplusplus
}
#endif

#endif /* mbedtls_md5.h */

Source - md5.c

The md5.c source code can also be found in the trunk on: md5.c.

/*
 *  RFC 1321 compliant MD5 implementation
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
/*
 *  The MD5 algorithm was designed by Ron Rivest in 1991.
 *
 *  http://www.ietf.org/rfc/rfc1321.txt
 */

#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_MD5_C)

#include "mbedtls/md5.h"

#include <string.h>

#if defined(MBEDTLS_SELF_TEST)
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#define mbedtls_printf printf
#endif /* MBEDTLS_PLATFORM_C */
#endif /* MBEDTLS_SELF_TEST */

#if !defined(MBEDTLS_MD5_ALT)

/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize( void *v, size_t n ) {
    volatile unsigned char *p = v; while( n-- ) *p++ = 0;
}

/*
 * 32-bit integer manipulation macros (little endian)
 */
#ifndef GET_UINT32_LE
#define GET_UINT32_LE(n,b,i)                            \
{                                                       \
    (n) = ( (uint32_t) (b)[(i)    ]       )             \
        | ( (uint32_t) (b)[(i) + 1] <<  8 )             \
        | ( (uint32_t) (b)[(i) + 2] << 16 )             \
        | ( (uint32_t) (b)[(i) + 3] << 24 );            \
}
#endif

#ifndef PUT_UINT32_LE
#define PUT_UINT32_LE(n,b,i)                                    \
{                                                               \
    (b)[(i)    ] = (unsigned char) ( ( (n)       ) & 0xFF );    \
    (b)[(i) + 1] = (unsigned char) ( ( (n) >>  8 ) & 0xFF );    \
    (b)[(i) + 2] = (unsigned char) ( ( (n) >> 16 ) & 0xFF );    \
    (b)[(i) + 3] = (unsigned char) ( ( (n) >> 24 ) & 0xFF );    \
}
#endif

void mbedtls_md5_init( mbedtls_md5_context *ctx )
{
    memset( ctx, 0, sizeof( mbedtls_md5_context ) );
}

void mbedtls_md5_free( mbedtls_md5_context *ctx )
{
    if( ctx == NULL )
        return;

    mbedtls_zeroize( ctx, sizeof( mbedtls_md5_context ) );
}

void mbedtls_md5_clone( mbedtls_md5_context *dst,
                        const mbedtls_md5_context *src )
{
    *dst = *src;
}

/*
 * MD5 context setup
 */
void mbedtls_md5_starts( mbedtls_md5_context *ctx )
{
    ctx->total[0] = 0;
    ctx->total[1] = 0;

    ctx->state[0] = 0x67452301;
    ctx->state[1] = 0xEFCDAB89;
    ctx->state[2] = 0x98BADCFE;
    ctx->state[3] = 0x10325476;
}

#if !defined(MBEDTLS_MD5_PROCESS_ALT)
void mbedtls_md5_process( mbedtls_md5_context *ctx, const unsigned char data[64] )
{
    uint32_t X[16], A, B, C, D;

    GET_UINT32_LE( X[ 0], data,  0 );
    GET_UINT32_LE( X[ 1], data,  4 );
    GET_UINT32_LE( X[ 2], data,  8 );
    GET_UINT32_LE( X[ 3], data, 12 );
    GET_UINT32_LE( X[ 4], data, 16 );
    GET_UINT32_LE( X[ 5], data, 20 );
    GET_UINT32_LE( X[ 6], data, 24 );
    GET_UINT32_LE( X[ 7], data, 28 );
    GET_UINT32_LE( X[ 8], data, 32 );
    GET_UINT32_LE( X[ 9], data, 36 );
    GET_UINT32_LE( X[10], data, 40 );
    GET_UINT32_LE( X[11], data, 44 );
    GET_UINT32_LE( X[12], data, 48 );
    GET_UINT32_LE( X[13], data, 52 );
    GET_UINT32_LE( X[14], data, 56 );
    GET_UINT32_LE( X[15], data, 60 );

#define S(x,n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))

#define P(a,b,c,d,k,s,t)                                \
{                                                       \
    a += F(b,c,d) + X[k] + t; a = S(a,s) + b;           \
}

    A = ctx->state[0];
    B = ctx->state[1];
    C = ctx->state[2];
    D = ctx->state[3];

#define F(x,y,z) (z ^ (x & (y ^ z)))

    P( A, B, C, D,  0,  7, 0xD76AA478 );
    P( D, A, B, C,  1, 12, 0xE8C7B756 );
    P( C, D, A, B,  2, 17, 0x242070DB );
    P( B, C, D, A,  3, 22, 0xC1BDCEEE );
    P( A, B, C, D,  4,  7, 0xF57C0FAF );
    P( D, A, B, C,  5, 12, 0x4787C62A );
    P( C, D, A, B,  6, 17, 0xA8304613 );
    P( B, C, D, A,  7, 22, 0xFD469501 );
    P( A, B, C, D,  8,  7, 0x698098D8 );
    P( D, A, B, C,  9, 12, 0x8B44F7AF );
    P( C, D, A, B, 10, 17, 0xFFFF5BB1 );
    P( B, C, D, A, 11, 22, 0x895CD7BE );
    P( A, B, C, D, 12,  7, 0x6B901122 );
    P( D, A, B, C, 13, 12, 0xFD987193 );
    P( C, D, A, B, 14, 17, 0xA679438E );
    P( B, C, D, A, 15, 22, 0x49B40821 );

#undef F

#define F(x,y,z) (y ^ (z & (x ^ y)))

    P( A, B, C, D,  1,  5, 0xF61E2562 );
    P( D, A, B, C,  6,  9, 0xC040B340 );
    P( C, D, A, B, 11, 14, 0x265E5A51 );
    P( B, C, D, A,  0, 20, 0xE9B6C7AA );
    P( A, B, C, D,  5,  5, 0xD62F105D );
    P( D, A, B, C, 10,  9, 0x02441453 );
    P( C, D, A, B, 15, 14, 0xD8A1E681 );
    P( B, C, D, A,  4, 20, 0xE7D3FBC8 );
    P( A, B, C, D,  9,  5, 0x21E1CDE6 );
    P( D, A, B, C, 14,  9, 0xC33707D6 );
    P( C, D, A, B,  3, 14, 0xF4D50D87 );
    P( B, C, D, A,  8, 20, 0x455A14ED );
    P( A, B, C, D, 13,  5, 0xA9E3E905 );
    P( D, A, B, C,  2,  9, 0xFCEFA3F8 );
    P( C, D, A, B,  7, 14, 0x676F02D9 );
    P( B, C, D, A, 12, 20, 0x8D2A4C8A );

#undef F

#define F(x,y,z) (x ^ y ^ z)

    P( A, B, C, D,  5,  4, 0xFFFA3942 );
    P( D, A, B, C,  8, 11, 0x8771F681 );
    P( C, D, A, B, 11, 16, 0x6D9D6122 );
    P( B, C, D, A, 14, 23, 0xFDE5380C );
    P( A, B, C, D,  1,  4, 0xA4BEEA44 );
    P( D, A, B, C,  4, 11, 0x4BDECFA9 );
    P( C, D, A, B,  7, 16, 0xF6BB4B60 );
    P( B, C, D, A, 10, 23, 0xBEBFBC70 );
    P( A, B, C, D, 13,  4, 0x289B7EC6 );
    P( D, A, B, C,  0, 11, 0xEAA127FA );
    P( C, D, A, B,  3, 16, 0xD4EF3085 );
    P( B, C, D, A,  6, 23, 0x04881D05 );
    P( A, B, C, D,  9,  4, 0xD9D4D039 );
    P( D, A, B, C, 12, 11, 0xE6DB99E5 );
    P( C, D, A, B, 15, 16, 0x1FA27CF8 );
    P( B, C, D, A,  2, 23, 0xC4AC5665 );

#undef F

#define F(x,y,z) (y ^ (x | ~z))

    P( A, B, C, D,  0,  6, 0xF4292244 );
    P( D, A, B, C,  7, 10, 0x432AFF97 );
    P( C, D, A, B, 14, 15, 0xAB9423A7 );
    P( B, C, D, A,  5, 21, 0xFC93A039 );
    P( A, B, C, D, 12,  6, 0x655B59C3 );
    P( D, A, B, C,  3, 10, 0x8F0CCC92 );
    P( C, D, A, B, 10, 15, 0xFFEFF47D );
    P( B, C, D, A,  1, 21, 0x85845DD1 );
    P( A, B, C, D,  8,  6, 0x6FA87E4F );
    P( D, A, B, C, 15, 10, 0xFE2CE6E0 );
    P( C, D, A, B,  6, 15, 0xA3014314 );
    P( B, C, D, A, 13, 21, 0x4E0811A1 );
    P( A, B, C, D,  4,  6, 0xF7537E82 );
    P( D, A, B, C, 11, 10, 0xBD3AF235 );
    P( C, D, A, B,  2, 15, 0x2AD7D2BB );
    P( B, C, D, A,  9, 21, 0xEB86D391 );

#undef F

    ctx->state[0] += A;
    ctx->state[1] += B;
    ctx->state[2] += C;
    ctx->state[3] += D;
}
#endif /* !MBEDTLS_MD5_PROCESS_ALT */

/*
 * MD5 process buffer
 */
void mbedtls_md5_update( mbedtls_md5_context *ctx, const unsigned char *input, size_t ilen )
{
    size_t fill;
    uint32_t left;

    if( ilen == 0 )
        return;

    left = ctx->total[0] & 0x3F;
    fill = 64 - left;

    ctx->total[0] += (uint32_t) ilen;
    ctx->total[0] &= 0xFFFFFFFF;

    if( ctx->total[0] < (uint32_t) ilen )
        ctx->total[1]++;

    if( left && ilen >= fill )
    {
        memcpy( (void *) (ctx->buffer + left), input, fill );
        mbedtls_md5_process( ctx, ctx->buffer );
        input += fill;
        ilen  -= fill;
        left = 0;
    }

    while( ilen >= 64 )
    {
        mbedtls_md5_process( ctx, input );
        input += 64;
        ilen  -= 64;
    }

    if( ilen > 0 )
    {
        memcpy( (void *) (ctx->buffer + left), input, ilen );
    }
}

static const unsigned char md5_padding[64] =
{
 0x80, 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
};

/*
 * MD5 final digest
 */
void mbedtls_md5_finish( mbedtls_md5_context *ctx, unsigned char output[16] )
{
    uint32_t last, padn;
    uint32_t high, low;
    unsigned char msglen[8];

    high = ( ctx->total[0] >> 29 )
         | ( ctx->total[1] <<  3 );
    low  = ( ctx->total[0] <<  3 );

    PUT_UINT32_LE( low,  msglen, 0 );
    PUT_UINT32_LE( high, msglen, 4 );

    last = ctx->total[0] & 0x3F;
    padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );

    mbedtls_md5_update( ctx, md5_padding, padn );
    mbedtls_md5_update( ctx, msglen, 8 );

    PUT_UINT32_LE( ctx->state[0], output,  0 );
    PUT_UINT32_LE( ctx->state[1], output,  4 );
    PUT_UINT32_LE( ctx->state[2], output,  8 );
    PUT_UINT32_LE( ctx->state[3], output, 12 );
}

#endif /* !MBEDTLS_MD5_ALT */

/*
 * output = MD5( input buffer )
 */
void mbedtls_md5( const unsigned char *input, size_t ilen, unsigned char output[16] )
{
    mbedtls_md5_context ctx;

    mbedtls_md5_init( &ctx );
    mbedtls_md5_starts( &ctx );
    mbedtls_md5_update( &ctx, input, ilen );
    mbedtls_md5_finish( &ctx, output );
    mbedtls_md5_free( &ctx );
}

#if defined(MBEDTLS_SELF_TEST)
/*
 * RFC 1321 test vectors
 */
static const unsigned char md5_test_buf[7][81] =
{
    { "" },
    { "a" },
    { "abc" },
    { "message digest" },
    { "abcdefghijklmnopqrstuvwxyz" },
    { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
    { "12345678901234567890123456789012345678901234567890123456789012" \
      "345678901234567890" }
};

static const int md5_test_buflen[7] =
{
    0, 1, 3, 14, 26, 62, 80
};

static const unsigned char md5_test_sum[7][16] =
{
    { 0xD4, 0x1D, 0x8C, 0xD9, 0x8F, 0x00, 0xB2, 0x04,
      0xE9, 0x80, 0x09, 0x98, 0xEC, 0xF8, 0x42, 0x7E },
    { 0x0C, 0xC1, 0x75, 0xB9, 0xC0, 0xF1, 0xB6, 0xA8,
      0x31, 0xC3, 0x99, 0xE2, 0x69, 0x77, 0x26, 0x61 },
    { 0x90, 0x01, 0x50, 0x98, 0x3C, 0xD2, 0x4F, 0xB0,
      0xD6, 0x96, 0x3F, 0x7D, 0x28, 0xE1, 0x7F, 0x72 },
    { 0xF9, 0x6B, 0x69, 0x7D, 0x7C, 0xB7, 0x93, 0x8D,
      0x52, 0x5A, 0x2F, 0x31, 0xAA, 0xF1, 0x61, 0xD0 },
    { 0xC3, 0xFC, 0xD3, 0xD7, 0x61, 0x92, 0xE4, 0x00,
      0x7D, 0xFB, 0x49, 0x6C, 0xCA, 0x67, 0xE1, 0x3B },
    { 0xD1, 0x74, 0xAB, 0x98, 0xD2, 0x77, 0xD9, 0xF5,
      0xA5, 0x61, 0x1C, 0x2C, 0x9F, 0x41, 0x9D, 0x9F },
    { 0x57, 0xED, 0xF4, 0xA2, 0x2B, 0xE3, 0xC9, 0x55,
      0xAC, 0x49, 0xDA, 0x2E, 0x21, 0x07, 0xB6, 0x7A }
};

/*
 * Checkup routine
 */
int mbedtls_md5_self_test( int verbose )
{
    int i;
    unsigned char md5sum[16];

    for( i = 0; i < 7; i++ )
    {
        if( verbose != 0 )
            mbedtls_printf( "  MD5 test #%d: ", i + 1 );

        mbedtls_md5( md5_test_buf[i], md5_test_buflen[i], md5sum );

        if( memcmp( md5sum, md5_test_sum[i], 16 ) != 0 )
        {
            if( verbose != 0 )
                mbedtls_printf( "failed\n" );

            return( 1 );
        }

        if( verbose != 0 )
            mbedtls_printf( "passed\n" );
    }

    if( verbose != 0 )
        mbedtls_printf( "\n" );

    return( 0 );
}

#endif /* MBEDTLS_SELF_TEST */

#endif /* MBEDTLS_MD5_C */