# Re: Rand generator (MD5)

This is the reply you want to look at.

JLC

Jean-Luc Cooke <jlcooke@xxxxxxxxxx> wrote:
// add two 64bit numbers using arrays of 2 32bit ints
unsigned int a[] = {0x01234567, 0x89abcdef},
b[] = {0xfedcba98, 0x76543210};
printf("{%.8x %.8x} += {%.8x %.8x}\n", a[0], a[1], b[0], b[1]);
add64(a,b); // a += b;
printf("{%.8x %.8x} += {%.8x %.8x}\n", a[0], a[1], b[0], b[1]);

void add64(unsigned int dest[], unsigned int arg[]) {
unsigned int t = dest[0];
if ((dest[0] += arg[0]) < t) {
dest[1]++;
}
dest[1] += arg[1];
}

Ravi <raviuday@xxxxxxxxx> wrote:
Hi,
Actually MD5 algo (RFC 1321) works good for me !!
But the catch is it uses 'unsigned long' and passes '64' for computing
16 byte hash value.
My micro cannot handle anything more than 32 bits !
So i typecasted 'unsigned long' as 'unsigned int' !! Is this fair
enough ????'
The result does look unique but i find many zeroes at the end !!

Can anything be changed to the MD5 code so that we can make it 32 bits
?
I am ok to get a 8 byte hash too !! But it should be unique :)

Thanks
Ravi

JiXian Yang wrote:
Ravi wrote:
Hi Group,

Is there a MD5 C-code that i could use, which does not use stdio.h /
string.h or any standard
libraries ? Coz, i do not have stdio on my 8051 micro. Need a simple
plain C-program.
Basically i need a random key gen. (MD5 preferable)
Please let me know if there is a way to work this out.

Thanks
- RK

http://www.ping.de/~flori/flott/exe/session/source/projects/c/dyncc/md5.c?tokens=C&back_url=/~flori/flott/exe//session/project/c/dyncc

Main Oneliners Ruby Perl C Scheme 17:04:05 projects/c/dyncc/md5.c
/*
* This code implements the MD5 message-digest algorithm.
* The algorithm is due to Ron Rivest. This code was
* written by Colin Plumb in 1993, no copyright is claimed.
* This code is in the public domain; do with it what you wish.
*
* Equivalent code is available from RSA Data Security, Inc.
* This code has been tested against that, and is equivalent,
* except that you don't need to include two pages of legalese
* with every copy.
*
* To compute the message digest of a chunk of bytes, declare an
* MD5Context structure, pass it to MD5Init, call MD5Update as
* needed on buffers full of bytes, and then call MD5Final, which
* will fill a supplied 16-byte array with the digest.
*/
#include <string.h> /* for memcpy() */
#include "md5.h"

#ifndef HIGHFIRST
#define byteReverse(buf, len) /* Nothing */
#else
void byteReverse(unsigned char *buf, unsigned longs);

#ifndef ASM_MD5
/*
* Note: this code is harmless on little-endian machines.
*/
void byteReverse(unsigned char *buf, unsigned longs)
{
uint32 t;
do {
t = (uint32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
((unsigned) buf[1] << 8 | buf[0]);
*(uint32 *) buf = t;
buf += 4;
} while (--longs);
}
#endif
#endif

/*
* Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
* initialization constants.
*/
void MD5Init(struct MD5Context *ctx)
{
ctx->buf[0] = 0x67452301;
ctx->buf[1] = 0xefcdab89;
ctx->buf[3] = 0x10325476;

ctx->bits[0] = 0;
ctx->bits[1] = 0;
}

/*
* Update context to reflect the concatenation of another buffer full
* of bytes.
*/
void MD5Update(struct MD5Context *ctx, unsigned char const *buf,
unsigned len)
{
uint32 t;

/* Update bitcount */

t = ctx->bits[0];
if ((ctx->bits[0] = t + ((uint32) len << 3)) < t)
ctx->bits[1]++; /* Carry from low to high */
ctx->bits[1] += len >> 29;

t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */

/* Handle any leading odd-sized chunks */

if (t) {
unsigned char *p = (unsigned char *) ctx->in + t;

t = 64 - t;
if (len < t) {
memcpy(p, buf, len);
return;
}
memcpy(p, buf, t);
byteReverse(ctx->in, 16);
MD5Transform(ctx->buf, (uint32 *) ctx->in);
buf += t;
len -= t;
}
/* Process data in 64-byte chunks */

while (len >= 64) {
memcpy(ctx->in, buf, 64);
byteReverse(ctx->in, 16);
MD5Transform(ctx->buf, (uint32 *) ctx->in);
buf += 64;
len -= 64;
}

/* Handle any remaining bytes of data. */

memcpy(ctx->in, buf, len);
}

/*
* Final wrapup - pad to 64-byte boundary with the bit pattern
* 1 0* (64-bit count of bits processed, MSB-first)
*/
void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
{
unsigned count;
unsigned char *p;

/* Compute number of bytes mod 64 */
count = (ctx->bits[0] >> 3) & 0x3F;

/* Set the first char of padding to 0x80. This is safe since there
is
always at least one byte free */
p = ctx->in + count;
*p++ = 0x80;

/* Bytes of padding needed to make 64 bytes */
count = 64 - 1 - count;

/* Pad out to 56 mod 64 */
if (count < 8) {
/* Two lots of padding: Pad the first block to 64 bytes */
memset(p, 0, count);
byteReverse(ctx->in, 16);
MD5Transform(ctx->buf, (uint32 *) ctx->in);

/* Now fill the next block with 56 bytes */
memset(ctx->in, 0, 56);
} else {
/* Pad block to 56 bytes */
memset(p, 0, count - 8);
}
byteReverse(ctx->in, 14);

/* Append length in bits and transform */
((uint32 *) ctx->in)[14] = ctx->bits[0];
((uint32 *) ctx->in)[15] = ctx->bits[1];

MD5Transform(ctx->buf, (uint32 *) ctx->in);
byteReverse((unsigned char *) ctx->buf, 4);
memcpy(digest, ctx->buf, 16);
memset(ctx, 0, sizeof(ctx)); /* In case it's sensitive */
}

#ifndef ASM_MD5

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#ifdef __PUREC__
#define MD5STEP(f, w, x, y, z, data, s) \
( w += f /*(x, y, z)*/ + data, w = w<<s | w>>(32-s), w += x )
#else
#define MD5STEP(f, w, x, y, z, data, s) \
( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
#endif

/*
* The core of the MD5 algorithm, this alters an existing MD5 hash to
* reflect the addition of 16 longwords of new data. MD5Update blocks
* the data and converts bytes into longwords for this routine.
*/
void MD5Transform(uint32 buf[4], uint32 const in[16])
{
register uint32 a, b, c, d;

a = buf[0];
b = buf[1];
c = buf[2];
d = buf[3];

#ifdef __PUREC__ /* PureC Weirdness... (GG) */
MD5STEP(F1(b,c,d), a, b, c, d, in[0] + 0xd76aa478L, 7);
MD5STEP(F1(a,b,c), d, a, b, c, in[1] + 0xe8c7b756L, 12);
MD5STEP(F1(d,a,b), c, d, a, b, in[2] + 0x242070dbL, 17);
MD5STEP(F1(c,d,a), b, c, d, a, in[3] + 0xc1bdceeeL, 22);
MD5STEP(F1(b,c,d), a, b, c, d, in[4] + 0xf57c0fafL, 7);
MD5STEP(F1(a,b,c), d, a, b, c, in[5] + 0x4787c62aL, 12);
MD5STEP(F1(d,a,b), c, d, a, b, in[6] + 0xa8304613L, 17);
MD5STEP(F1(c,d,a), b, c, d, a, in[7] + 0xfd469501L, 22);
MD5STEP(F1(b,c,d), a, b, c, d, in[8] + 0x698098d8L, 7);
MD5STEP(F1(a,b,c), d, a, b, c, in[9] + 0x8b44f7afL, 12);
MD5STEP(F1(d,a,b), c, d, a, b, in[10] + 0xffff5bb1L, 17);
MD5STEP(F1(c,d,a), b, c, d, a, in[11] + 0x895cd7beL, 22);
MD5STEP(F1(b,c,d), a, b, c, d, in[12] + 0x6b901122L, 7);
MD5STEP(F1(a,b,c), d, a, b, c, in[13] + 0xfd987193L, 12);
MD5STEP(F1(d,a,b), c, d, a, b, in[14] + 0xa679438eL, 17);
MD5STEP(F1(c,d,a), b, c, d, a, in[15] + 0x49b40821L, 22);

MD5STEP(F2(b,c,d), a, b, c, d, in[1] + 0xf61e2562L, 5);
MD5STEP(F2(a,b,c), d, a, b, c, in[6] + 0xc040b340L, 9);
MD5STEP(F2(d,a,b), c, d, a, b, in[11] + 0x265e5a51L, 14);
MD5STEP(F2(c,d,a), b, c, d, a, in[0] + 0xe9b6c7aaL, 20);
MD5STEP(F2(b,c,d), a, b, c, d, in[5] + 0xd62f105dL, 5);
MD5STEP(F2(a,b,c), d, a, b, c, in[10] + 0x02441453L, 9);
MD5STEP(F2(d,a,b), c, d, a, b, in[15] + 0xd8a1e681L, 14);
MD5STEP(F2(c,d,a), b, c, d, a, in[4] + 0xe7d3fbc8L, 20);
MD5STEP(F2(b,c,d), a, b, c, d, in[9] + 0x21e1cde6L, 5);
MD5STEP(F2(a,b,c), d, a, b, c, in[14] + 0xc33707d6L, 9);
MD5STEP(F2(d,a,b), c, d, a, b, in[3] + 0xf4d50d87L, 14);
MD5STEP(F2(c,d,a), b, c, d, a, in[8] + 0x455a14edL, 20);
MD5STEP(F2(b,c,d), a, b, c, d, in[13] + 0xa9e3e905L, 5);
MD5STEP(F2(a,b,c), d, a, b, c, in[2] + 0xfcefa3f8L, 9);
MD5STEP(F2(d,a,b), c, d, a, b, in[7] + 0x676f02d9L, 14);
MD5STEP(F2(c,d,a), b, c, d, a, in[12] + 0x8d2a4c8aL, 20);

MD5STEP(F3(b,c,d), a, b, c, d, in[5] + 0xfffa3942L, 4);
MD5STEP(F3(a,b,c), d, a, b, c, in[8] + 0x8771f681L, 11);
MD5STEP(F3(d,a,b), c, d, a, b, in[11] + 0x6d9d6122L, 16);
MD5STEP(F3(c,d,a), b, c, d, a, in[14] + 0xfde5380cL, 23);
MD5STEP(F3(b,c,d), a, b, c, d, in[1] + 0xa4beea44L, 4);
MD5STEP(F3(a,b,c), d, a, b, c, in[4] + 0x4bdecfa9L, 11);
MD5STEP(F3(d,a,b), c, d, a, b, in[7] + 0xf6bb4b60L, 16);
MD5STEP(F3(c,d,a), b, c, d, a, in[10] + 0xbebfbc70L, 23);
MD5STEP(F3(b,c,d), a, b, c, d, in[13] + 0x289b7ec6L, 4);
MD5STEP(F3(a,b,c), d, a, b, c, in[0] + 0xeaa127faL, 11);
MD5STEP(F3(d,a,b), c, d, a, b, in[3] + 0xd4ef3085L, 16);
MD5STEP(F3(c,d,a), b, c, d, a, in[6] + 0x04881d05L, 23);
MD5STEP(F3(b,c,d), a, b, c, d, in[9] + 0xd9d4d039L, 4);
MD5STEP(F3(a,b,c), d, a, b, c, in[12] + 0xe6db99e5L, 11);
MD5STEP(F3(d,a,b), c, d, a, b, in[15] + 0x1fa27cf8L, 16);
MD5STEP(F3(c,d,a), b, c, d, a, in[2] + 0xc4ac5665L, 23);

MD5STEP(F4(b,c,d), a, b, c, d, in[0] + 0xf4292244L, 6);
MD5STEP(F4(a,b,c), d, a, b, c, in[7] + 0x432aff97L, 10);
MD5STEP(F4(d,a,b), c, d, a, b, in[14] + 0xab9423a7L, 15);
MD5STEP(F4(c,d,a), b, c, d, a, in[5] + 0xfc93a039L, 21);
MD5STEP(F4(b,c,d), a, b, c, d, in[12] + 0x655b59c3L, 6);
MD5STEP(F4(a,b,c), d, a, b, c, in[3] + 0x8f0ccc92L, 10);
MD5STEP(F4(d,a,b), c, d, a, b, in[10] + 0xffeff47dL, 15);
MD5STEP(F4(c,d,a), b, c, d, a, in[1] + 0x85845dd1L, 21);
MD5STEP(F4(b,c,d), a, b, c, d, in[8] + 0x6fa87e4fL, 6);
MD5STEP(F4(a,b,c), d, a, b, c, in[15] + 0xfe2ce6e0L, 10);
MD5STEP(F4(d,a,b), c, d, a, b, in[6] + 0xa3014314L, 15);
MD5STEP(F4(c,d,a), b, c, d, a, in[13] + 0x4e0811a1L, 21);
MD5STEP(F4(b,c,d), a, b, c, d, in[4] + 0xf7537e82L, 6);
MD5STEP(F4(a,b,c), d, a, b, c, in[11] + 0xbd3af235L, 10);
MD5STEP(F4(d,a,b), c, d, a, b, in[2] + 0x2ad7d2bbL, 15);
MD5STEP(F4(c,d,a), b, c, d, a, in[9] + 0xeb86d391L, 21);
#else
MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
#endif

buf[0] += a;
buf[1] += b;
buf[2] += c;
buf[3] += d;
}

#endif

--------------------------------------------------------------------------------

Last changed at 2005-06-28 02:59:39 ? ? Florian Frank <flori@xxxxxxx>

memcpy() :

void memcpy(void *dest, const void *src, unsigned int n)
{
unsigned int i;
char *tod = (char *)dest;
char *frs = (char *)src;
if (n == 0) return;
for (i=0; i<n; i++)
tod[i]=frs[i];
}

--

--
.

## Relevant Pages

• Re: Rand generator (MD5)
... YOu do not have MD5. ... It does not sound to me like your hash implimentation is very ... void byteReverse(unsigned char *buf, unsigned longs); ...
(sci.crypt)
• Re: Rand generator (MD5)
... Is there a MD5 C-code that i could use, which does not use stdio.h / ... void byteReverse(unsigned char *buf, unsigned longs); ...
(sci.crypt)
• Re: Rand generator (MD5)
... Can anything be changed to the MD5 code so that we can make it 32 bits ... void byteReverse(unsigned char *buf, unsigned longs); ...
(sci.crypt)
• Re: Rand generator (MD5)
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(sci.crypt)
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