--- /dev/null
+/*
+** ********************************************************************
+** 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
+** MDupdate(&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,
+** MDupdate(&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.
+** If the machine stores the least-significant byte of an int in the
+** least-addressed byte (e.g., VAX and 8086), then LOWBYTEFIRST
+** should be set to TRUE. Otherwise (e.g., SUNS), LOWBYTEFIRST
+** should be set to FALSE. Note that on machines with LOWBYTEFIRST
+** FALSE the routine MDupdate modifies has a side-effect on its input
+** array (the order of bytes in each word are reversed). If this is
+** undesired a call to MDreverse(X) can reverse the bytes of X back
+** into order after each call to MDupdate.
+**
+** NOTE: LOWBYTEFIRST removed by Eric Rosenquist in favour of run-time
+** detection to simplify build process.
+*/
+
+#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)
+
+/* MDprint(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
+MDprint(MDp)
+MDptr 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);
+}
+
+/* MDbegin(MDp)
+** Initialize message digest buffer MDp.
+** This is a user-callable routine.
+*/
+void
+MDbegin(MDp)
+MDptr 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;
+}
+
+/* MDreverse(X)
+** Reverse the byte-ordering of every int in X.
+** Assumes X is an array of 16 ints.
+** The macro revx reverses the byte-ordering of the next word of X.
+*/
+#define revx { t = (*X << 16) | (*X >> 16); \
+ *X++ = ((t & 0xFF00FF00) >> 8) | ((t & 0x00FF00FF) << 8); }
+MDreverse(X)
+unsigned int *X;
+{ register unsigned int t;
+revx; revx; revx; revx; revx; revx; revx; revx;
+revx; revx; revx; revx; revx; revx; revx; revx;
+}
+
+/* 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,X)
+MDptr MDp;
+unsigned int *X;
+{
+register unsigned int tmp, A, B, C, D;
+static int low_byte_first = -1;
+
+if (low_byte_first == -1) {
+ low_byte_first = (htons((unsigned short int)1) != 1);
+}
+
+if (low_byte_first == 0) {
+ MDreverse(X);
+}
+
+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;
+}
+
+/* MDupdate(MDp,X,count)
+** Input: MDp -- an MDptr
+** 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 MDupdate 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
+MDupdate(MDp,X,count)
+MDptr 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: MDupdate 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,(unsigned int *)X);
+ }
+else if (count > 512) /* Check for count too large */
+ { printf("\nError: MDupdate 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 */
+ 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,(unsigned int *)XX);
+ }
+ else /* need to do two blocks to finish up */
+ { MDblock(MDp,(unsigned int *)XX);
+ for (i=0;i<56;i++) XX[i] = 0;
+ for (i=0;i<8;i++) XX[56+i] = MDp->count[i];
+ MDblock(MDp,(unsigned int *)XX);
+ }
+ /* Set flag saying we're done with MD computation */
+ MDp->done = 1;
+ }
+}
+
+/*
+** End of md4.c
+****************************(cut)***********************************/
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