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