/*
** ********************************************************************
** md4.c -- Implementation of MD4 Message Digest Algorithm **
** Updated: 2/16/90 by Ronald L. Rivest **
** (C) 1990 RSA Data Security, Inc. **
** ********************************************************************
*/
/*
** To use MD4:
** -- Include md4.h in your program
** -- Declare an MDstruct MD to hold the state of the digest
** computation.
** -- Initialize MD using MDbegin(&MD)
** -- For each full block (64 bytes) X you wish to process, call
** MD4Update(&MD,X,512)
** (512 is the number of bits in a full block.)
** -- For the last block (less than 64 bytes) you wish to process,
** MD4Update(&MD,X,n)
** where n is the number of bits in the partial block. A partial
** block terminates the computation, so every MD computation
** should terminate by processing a partial block, even if it
** has n = 0.
** -- The message digest is available in MD.buffer[0] ...
** MD.buffer[3]. (Least-significant byte of each word
** should be output first.)
** -- You can print out the digest using MDprint(&MD)
*/
/* Implementation notes:
** This implementation assumes that ints are 32-bit quantities.
*/
#define TRUE 1
#define FALSE 0
/* Compile-time includes
*/
#include <stdio.h>
#include "md4.h"
#include "pppd.h"
/* Compile-time declarations of MD4 "magic constants".
*/
#define I0 0x67452301 /* Initial values for MD buffer */
#define I1 0xefcdab89
#define I2 0x98badcfe
#define I3 0x10325476
#define C2 013240474631 /* round 2 constant = sqrt(2) in octal */
#define C3 015666365641 /* round 3 constant = sqrt(3) in octal */
/* C2 and C3 are from Knuth, The Art of Programming, Volume 2
** (Seminumerical Algorithms), Second Edition (1981), Addison-Wesley.
** Table 2, page 660.
*/
#define fs1 3 /* round 1 shift amounts */
#define fs2 7
#define fs3 11
#define fs4 19
#define gs1 3 /* round 2 shift amounts */
#define gs2 5
#define gs3 9
#define gs4 13
#define hs1 3 /* round 3 shift amounts */
#define hs2 9
#define hs3 11
#define hs4 15
/* Compile-time macro declarations for MD4.
** Note: The "rot" operator uses the variable "tmp".
** It assumes tmp is declared as unsigned int, so that the >>
** operator will shift in zeros rather than extending the sign bit.
*/
#define f(X,Y,Z) ((X&Y) | ((~X)&Z))
#define g(X,Y,Z) ((X&Y) | (X&Z) | (Y&Z))
#define h(X,Y,Z) (X^Y^Z)
#define rot(X,S) (tmp=X,(tmp<<S) | (tmp>>(32-S)))
#define ff(A,B,C,D,i,s) A = rot((A + f(B,C,D) + X[i]),s)
#define gg(A,B,C,D,i,s) A = rot((A + g(B,C,D) + X[i] + C2),s)
#define hh(A,B,C,D,i,s) A = rot((A + h(B,C,D) + X[i] + C3),s)
/* MD4print(MDp)
** Print message digest buffer MDp as 32 hexadecimal digits.
** Order is from low-order byte of buffer[0] to high-order byte of
** buffer[3].
** Each byte is printed with high-order hexadecimal digit first.
** This is a user-callable routine.
*/
void
MD4Print(MDp)
MD4_CTX *MDp;
{
int i,j;
for (i=0;i<4;i++)
for (j=0;j<32;j=j+8)
printf("%02x",(MDp->buffer[i]>>j) & 0xFF);
}
/* MD4Init(MDp)
** Initialize message digest buffer MDp.
** This is a user-callable routine.
*/
void
MD4Init(MDp)
MD4_CTX *MDp;
{
int i;
MDp->buffer[0] = I0;
MDp->buffer[1] = I1;
MDp->buffer[2] = I2;
MDp->buffer[3] = I3;
for (i=0;i<8;i++) MDp->count[i] = 0;
MDp->done = 0;
}
/* MDblock(MDp,X)
** Update message digest buffer MDp->buffer using 16-word data block X.
** Assumes all 16 words of X are full of data.
** Does not update MDp->count.
** This routine is not user-callable.
*/
static void
MDblock(MDp,Xb)
MD4_CTX *MDp;
unsigned char *Xb;
{
register unsigned int tmp, A, B, C, D;
unsigned int X[16];
int i;
for (i = 0; i < 16; ++i) {
X[i] = Xb[0] + (Xb[1] << 8) + (Xb[2] << 16) + (Xb[3] << 24);
Xb += 4;
}
A = MDp->buffer[0];
B = MDp->buffer[1];
C = MDp->buffer[2];
D = MDp->buffer[3];
/* Update the message digest buffer */
ff(A , B , C , D , 0 , fs1); /* Round 1 */
ff(D , A , B , C , 1 , fs2);
ff(C , D , A , B , 2 , fs3);
ff(B , C , D , A , 3 , fs4);
ff(A , B , C , D , 4 , fs1);
ff(D , A , B , C , 5 , fs2);
ff(C , D , A , B , 6 , fs3);
ff(B , C , D , A , 7 , fs4);
ff(A , B , C , D , 8 , fs1);
ff(D , A , B , C , 9 , fs2);
ff(C , D , A , B , 10 , fs3);
ff(B , C , D , A , 11 , fs4);
ff(A , B , C , D , 12 , fs1);
ff(D , A , B , C , 13 , fs2);
ff(C , D , A , B , 14 , fs3);
ff(B , C , D , A , 15 , fs4);
gg(A , B , C , D , 0 , gs1); /* Round 2 */
gg(D , A , B , C , 4 , gs2);
gg(C , D , A , B , 8 , gs3);
gg(B , C , D , A , 12 , gs4);
gg(A , B , C , D , 1 , gs1);
gg(D , A , B , C , 5 , gs2);
gg(C , D , A , B , 9 , gs3);
gg(B , C , D , A , 13 , gs4);
gg(A , B , C , D , 2 , gs1);
gg(D , A , B , C , 6 , gs2);
gg(C , D , A , B , 10 , gs3);
gg(B , C , D , A , 14 , gs4);
gg(A , B , C , D , 3 , gs1);
gg(D , A , B , C , 7 , gs2);
gg(C , D , A , B , 11 , gs3);
gg(B , C , D , A , 15 , gs4);
hh(A , B , C , D , 0 , hs1); /* Round 3 */
hh(D , A , B , C , 8 , hs2);
hh(C , D , A , B , 4 , hs3);
hh(B , C , D , A , 12 , hs4);
hh(A , B , C , D , 2 , hs1);
hh(D , A , B , C , 10 , hs2);
hh(C , D , A , B , 6 , hs3);
hh(B , C , D , A , 14 , hs4);
hh(A , B , C , D , 1 , hs1);
hh(D , A , B , C , 9 , hs2);
hh(C , D , A , B , 5 , hs3);
hh(B , C , D , A , 13 , hs4);
hh(A , B , C , D , 3 , hs1);
hh(D , A , B , C , 11 , hs2);
hh(C , D , A , B , 7 , hs3);
hh(B , C , D , A , 15 , hs4);
MDp->buffer[0] += A;
MDp->buffer[1] += B;
MDp->buffer[2] += C;
MDp->buffer[3] += D;
}
/* MD4Update(MDp,X,count)
** Input: X -- a pointer to an array of unsigned characters.
** count -- the number of bits of X to use.
** (if not a multiple of 8, uses high bits of last byte.)
** Update MDp using the number of bits of X given by count.
** This is the basic input routine for an MD4 user.
** The routine completes the MD computation when count < 512, so
** every MD computation should end with one call to MD4Update with a
** count less than 512. A call with count 0 will be ignored if the
** MD has already been terminated (done != 0), so an extra call with
** count 0 can be given as a "courtesy close" to force termination
** if desired.
*/
void
MD4Update(MDp,X,count)
MD4_CTX *MDp;
unsigned char *X;
unsigned int count;
{
unsigned int i, tmp, bit, byte, mask;
unsigned char XX[64];
unsigned char *p;
/* return with no error if this is a courtesy close with count
** zero and MDp->done is true.
*/
if (count == 0 && MDp->done) return;
/* check to see if MD is already done and report error */
if (MDp->done)
{ printf("\nError: MD4Update MD already done."); return; }
/* Add count to MDp->count */
tmp = count;
p = MDp->count;
while (tmp)
{ tmp += *p;
*p++ = tmp;
tmp = tmp >> 8;
}
/* Process data */
if (count == 512)
{ /* Full block of data to handle */
MDblock(MDp,X);
}
else if (count > 512) /* Check for count too large */
{
printf("\nError: MD4Update called with illegal count value %d.",
count);
return;
}
else /* partial block -- must be last block so finish up */
{
/* Find out how many bytes and residual bits there are */
byte = count >> 3;
bit = count & 7;
/* Copy X into XX since we need to modify it */
if (count)
for (i=0;i<=byte;i++) XX[i] = X[i];
for (i=byte+1;i<64;i++) XX[i] = 0;
/* Add padding '1' bit and low-order zeros in last byte */
mask = 1 << (7 - bit);
XX[byte] = (XX[byte] | mask) & ~( mask - 1);
/* If room for bit count, finish up with this block */
if (byte <= 55)
{
for (i=0;i<8;i++) XX[56+i] = MDp->count[i];
MDblock(MDp,XX);
}
else /* need to do two blocks to finish up */
{
MDblock(MDp,XX);
for (i=0;i<56;i++) XX[i] = 0;
for (i=0;i<8;i++) XX[56+i] = MDp->count[i];
MDblock(MDp,XX);
}
/* Set flag saying we're done with MD computation */
MDp->done = 1;
}
}
/*
** Finish up MD4 computation and return message digest.
*/
void
MD4Final(buf, MD)
unsigned char *buf;
MD4_CTX *MD;
{
int i, j;
unsigned int w;
MD4Update(MD, NULL, 0);
for (i = 0; i < 4; ++i) {
w = MD->buffer[i];
for (j = 0; j < 4; ++j) {
*buf++ = w;
w >>= 8;
}
}
}
/*
** End of md4.c
****************************(cut)***********************************/