MD5 implementation in C

md5

MD5 implementation in C

main.c

//
//  main.c
//  md5
//
//  Created by qingpei on 28/12/2016.
//  Copyright © 2016 sansi. All rights reserved.
//

#include "md5.h"
#include <stdio.h>
#include <stdlib.h>

int main(int argc, const char *argv[]) {
  FILE *f;
  int i, j;
  md5_context ctx;
  unsigned char buf[1000];
  unsigned char md5sum[16];

  if (argc < 2) {
    printf("Usage: md5 filename");
  } else {
    if (!(f = fopen(argv[1], "rb"))) {
      perror("fopen");
      return (1);
    }

    md5_starts(&ctx);

    while ((i = fread(buf, 1, sizeof(buf), f)) > 0) {
      md5_update(&ctx, buf, i);
    }

    md5_finish(&ctx, md5sum);

    for (j = 0; j < 16; j++) {
      printf("%02x", md5sum[j]);
    }

    printf("  %s\n", argv[1]);
  }

  return (0);
}

Makefile

CC=gcc
CFLAGS=-I. -g -Wall -O3
DEPS = md5.h
OBJ = md5.o main.o

TARGET = md5
TESTFILE = Makefile

%.o: %.c $(DEPS)
	$(CC) -c -o $@ $< $(CFLAGS)

$(TARGET): $(OBJ)
	gcc -o $@ $^ $(CFLAGS)
	
clean:
	rm -f *.o *~ $(TARGET)
	
test:
	# generate md5 for the test file
	$(TARGET) $(TESTFILE)

md5.c

/*
 *  RFC 1321 compliant MD5 implementation
 *
 *  Copyright (C) 2001-2003  Christophe Devine
 *
 *  This program 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <string.h>

#include "md5.h"

#define GET_UINT32(n, b, i)                                                    \
  {                                                                            \
    (n) = ((uint32)(b)[(i)]) | ((uint32)(b)[(i) + 1] << 8) |                   \
          ((uint32)(b)[(i) + 2] << 16) | ((uint32)(b)[(i) + 3] << 24);         \
  }

#define PUT_UINT32(n, b, i)                                                    \
  {                                                                            \
    (b)[(i)] = (uint8)((n));                                                   \
    (b)[(i) + 1] = (uint8)((n) >> 8);                                          \
    (b)[(i) + 2] = (uint8)((n) >> 16);                                         \
    (b)[(i) + 3] = (uint8)((n) >> 24);                                         \
  }

void md5_starts(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;
}

void md5_process(md5_context *ctx, uint8 data[64]) {
  uint32 X[16], A, B, C, D;

  GET_UINT32(X[0], data, 0);
  GET_UINT32(X[1], data, 4);
  GET_UINT32(X[2], data, 8);
  GET_UINT32(X[3], data, 12);
  GET_UINT32(X[4], data, 16);
  GET_UINT32(X[5], data, 20);
  GET_UINT32(X[6], data, 24);
  GET_UINT32(X[7], data, 28);
  GET_UINT32(X[8], data, 32);
  GET_UINT32(X[9], data, 36);
  GET_UINT32(X[10], data, 40);
  GET_UINT32(X[11], data, 44);
  GET_UINT32(X[12], data, 48);
  GET_UINT32(X[13], data, 52);
  GET_UINT32(X[14], data, 56);
  GET_UINT32(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;
}

void md5_update(md5_context *ctx, uint8 *input, uint32 length) {
  uint32 left, fill;

  if (!length)
    return;

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

  ctx->total[0] += length;
  ctx->total[0] &= 0xFFFFFFFF;

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

  if (left && length >= fill) {
    memcpy((void *)(ctx->buffer + left), (void *)input, fill);
    md5_process(ctx, ctx->buffer);
    length -= fill;
    input += fill;
    left = 0;
  }

  while (length >= 64) {
    md5_process(ctx, input);
    length -= 64;
    input += 64;
  }

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

static uint8 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};

void md5_finish(md5_context *ctx, uint8 digest[16]) {
  uint32 last, padn;
  uint32 high, low;
  uint8 msglen[8];

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

  PUT_UINT32(low, msglen, 0);
  PUT_UINT32(high, msglen, 4);

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

  md5_update(ctx, md5_padding, padn);
  md5_update(ctx, msglen, 8);

  PUT_UINT32(ctx->state[0], digest, 0);
  PUT_UINT32(ctx->state[1], digest, 4);
  PUT_UINT32(ctx->state[2], digest, 8);
  PUT_UINT32(ctx->state[3], digest, 12);
}

#ifdef TEST

#endif

md5.h

#ifndef __md5_h__
#define __md5_h__

#ifndef uint8
#define uint8 unsigned char
#endif

#ifndef uint32
#define uint32 unsigned long int
#endif

typedef struct {
  uint32 total[2];
  uint32 state[4];
  uint8 buffer[64];
} md5_context;

void md5_starts(md5_context *ctx);
void md5_update(md5_context *ctx, uint8 *input, uint32 length);
void md5_finish(md5_context *ctx, uint8 digest[16]);

#endif // __md5_h__

$ diff main.orig.c main.rv.c
34c34
< md5_update(&ctx, buf, i);

  md5_update(&ctx, buf, i-1);

$ cat YMCABNK.txt
YMCABNK

$ ./md5.orig YMCABNK.txt
306957a67dea9a3b1f21c20f4196ee93 YMCABNK.txt

$ ./md5rv YMCABNK.txt
11c77a82e87cc87e18c4b3e0063775f8 YMCABNK.txt

Your original doesn't match the results of
https://hashtoolkit.com/generate-hash/?text=YMCABNK
but revised main.rv.c matched.
So, please check my results and revise your "main.c" of MD5 implementation in C.