sha1_impl.cc | searchcode

/elements/ipsec/sha1_impl.cc

https://github.com/bhesmans/click
C++ | 656 lines | 514 code | 57 blank | 85 comment | 47 complexity | e5734a642eeb8e91bedc06699219c495 MD5 | raw file
Possible License(s): GPL-2.0, BSD-3-Clause

/* crypto/sha/sha1dgst.c */
/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
#include "sha1_impl.hh"




#define ULONG	unsigned long
#define UCHAR	unsigned char
#define UINT	unsigned int

#undef c2nl
#define c2nl(c,l)	(l =(((unsigned long)(*((c)++)))<<24), \
			 l|=(((unsigned long)(*((c)++)))<<16), \
			 l|=(((unsigned long)(*((c)++)))<< 8), \
			 l|=(((unsigned long)(*((c)++)))    ))

#undef p_c2nl
#define p_c2nl(c,l,n)	{ \
			switch (n) { \
			case 0: l =((unsigned long)(*((c)++)))<<24; \
			case 1: l|=((unsigned long)(*((c)++)))<<16; \
			case 2: l|=((unsigned long)(*((c)++)))<< 8; \
			case 3: l|=((unsigned long)(*((c)++))); \
				} \
			}

#undef c2nl_p
/* NOTE the pointer is not incremented at the end of this */
#define c2nl_p(c,l,n)	{ \
			l=0; \
			(c)+=n; \
			switch (n) { \
			case 3: l =((unsigned long)(*(--(c))))<< 8; \
			case 2: l|=((unsigned long)(*(--(c))))<<16; \
			case 1: l|=((unsigned long)(*(--(c))))<<24; \
				} \
			}

#undef p_c2nl_p
#define p_c2nl_p(c,l,sc,len) { \
			switch (sc) \
				{ \
			case 0: l =((unsigned long)(*((c)++)))<<24; \
				if (--len == 0) break; \
			case 1: l|=((unsigned long)(*((c)++)))<<16; \
				if (--len == 0) break; \
			case 2: l|=((unsigned long)(*((c)++)))<< 8; \
				} \
			}

#undef nl2c
#define nl2c(l,c)	(*((c)++)=(unsigned char)(((l)>>24)&0xff), \
			 *((c)++)=(unsigned char)(((l)>>16)&0xff), \
			 *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
			 *((c)++)=(unsigned char)(((l)    )&0xff))

#undef c2l
#define c2l(c,l)	(l =(((unsigned long)(*((c)++)))    ), \
			 l|=(((unsigned long)(*((c)++)))<< 8), \
			 l|=(((unsigned long)(*((c)++)))<<16), \
			 l|=(((unsigned long)(*((c)++)))<<24))

#undef p_c2l
#define p_c2l(c,l,n)	{ \
			switch (n) { \
			case 0: l =((unsigned long)(*((c)++))); \
			case 1: l|=((unsigned long)(*((c)++)))<< 8; \
			case 2: l|=((unsigned long)(*((c)++)))<<16; \
			case 3: l|=((unsigned long)(*((c)++)))<<24; \
				} \
			}

#undef c2l_p
/* NOTE the pointer is not incremented at the end of this */
#define c2l_p(c,l,n)	{ \
			l=0; \
			(c)+=n; \
			switch (n) { \
			case 3: l =((unsigned long)(*(--(c))))<<16; \
			case 2: l|=((unsigned long)(*(--(c))))<< 8; \
			case 1: l|=((unsigned long)(*(--(c)))); \
				} \
			}

#undef p_c2l_p
#define p_c2l_p(c,l,sc,len) { \
			switch (sc) \
				{ \
			case 0: l =((unsigned long)(*((c)++))); \
				if (--len == 0) break; \
			case 1: l|=((unsigned long)(*((c)++)))<< 8; \
				if (--len == 0) break; \
			case 2: l|=((unsigned long)(*((c)++)))<<16; \
				} \
			}

#undef l2c
#define l2c(l,c)	(*((c)++)=(unsigned char)(((l)    )&0xff), \
			 *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
			 *((c)++)=(unsigned char)(((l)>>16)&0xff), \
			 *((c)++)=(unsigned char)(((l)>>24)&0xff))

#undef ROTATE
#if defined(WIN32)
#define ROTATE(a,n)     _lrotl(a,n)
#else
#define ROTATE(a,n)     (((a)<<(n))|(((a)&0xffffffff)>>(32-(n))))
#endif

/* A nice byte order reversal from Wei Dai <weidai@eskimo.com> */
#if defined(WIN32)
/* 5 instructions with rotate instruction, else 9 */
#define Endian_Reverse32(a) \
	{ \
	unsigned long l=(a); \
	(a)=((ROTATE(l,8)&0x00FF00FF)|(ROTATE(l,24)&0xFF00FF00)); \
	}
#else
/* 6 instructions with rotate instruction, else 8 */
#define Endian_Reverse32(a) \
	{ \
	unsigned long l=(a); \
	l=(((l&0xFF00FF00)>>8L)|((l&0x00FF00FF)<<8L)); \
	(a)=ROTATE(l,16L); \
	}
#endif

/* As  pointed out by Wei Dai <weidai@eskimo.com>, F() below can be
 * simplified to the code in F_00_19.  Wei attributes these optimisations
 * to Peter Gutmann's SHS code, and he attributes it to Rich Schroeppel.
 * #define F(x,y,z) (((x) & (y))  |  ((~(x)) & (z)))
 * I've just become aware of another tweak to be made, again from Wei Dai,
 * in F_40_59, (x&a)|(y&a) -> (x|y)&a
 */
#define	F_00_19(b,c,d)	((((c) ^ (d)) & (b)) ^ (d))
#define	F_20_39(b,c,d)	((b) ^ (c) ^ (d))
#define F_40_59(b,c,d)	(((b) & (c)) | (((b)|(c)) & (d)))
#define	F_60_79(b,c,d)	F_20_39(b,c,d)

#ifdef SHA_0
#undef Xupdate
#define Xupdate(a,i,ia,ib,ic,id) X[(i)&0x0f]=(a)=\
	(ia[(i)&0x0f]^ib[((i)+2)&0x0f]^ic[((i)+8)&0x0f]^id[((i)+13)&0x0f]);
#endif
#ifdef SHA_1
#undef Xupdate
#define Xupdate(a,i,ia,ib,ic,id) (a)=\
	(ia[(i)&0x0f]^ib[((i)+2)&0x0f]^ic[((i)+8)&0x0f]^id[((i)+13)&0x0f]);\
	X[(i)&0x0f]=(a)=ROTATE((a),1);
#endif

#define BODY_00_15(i,a,b,c,d,e,f,xa) \
	(f)=xa[i]+(e)+K_00_19+ROTATE((a),5)+F_00_19((b),(c),(d)); \
	(b)=ROTATE((b),30);

#define BODY_16_19(i,a,b,c,d,e,f,xa,xb,xc,xd) \
	Xupdate(f,i,xa,xb,xc,xd); \
	(f)+=(e)+K_00_19+ROTATE((a),5)+F_00_19((b),(c),(d)); \
	(b)=ROTATE((b),30);

#define BODY_20_31(i,a,b,c,d,e,f,xa,xb,xc,xd) \
	Xupdate(f,i,xa,xb,xc,xd); \
	(f)+=(e)+K_20_39+ROTATE((a),5)+F_20_39((b),(c),(d)); \
	(b)=ROTATE((b),30);

#define BODY_32_39(i,a,b,c,d,e,f,xa) \
	Xupdate(f,i,xa,xa,xa,xa); \
	(f)+=(e)+K_20_39+ROTATE((a),5)+F_20_39((b),(c),(d)); \
	(b)=ROTATE((b),30);

#define BODY_40_59(i,a,b,c,d,e,f,xa) \
	Xupdate(f,i,xa,xa,xa,xa); \
	(f)+=(e)+K_40_59+ROTATE((a),5)+F_40_59((b),(c),(d)); \
	(b)=ROTATE((b),30);

#define BODY_60_79(i,a,b,c,d,e,f,xa) \
	Xupdate(f,i,xa,xa,xa,xa); \
	(f)=X[(i)&0x0f]+(e)+K_60_79+ROTATE((a),5)+F_60_79((b),(c),(d)); \
	(b)=ROTATE((b),30);


const char SHA1_version[] = "SHA1 part of SSLeay 0.8.2b 08-Jan-1998";

/* Implemented from SHA-1 document - The Secure Hash Algorithm
 */

#define INIT_DATA_h0 (unsigned long)0x67452301L
#define INIT_DATA_h1 (unsigned long)0xefcdab89L
#define INIT_DATA_h2 (unsigned long)0x98badcfeL
#define INIT_DATA_h3 (unsigned long)0x10325476L
#define INIT_DATA_h4 (unsigned long)0xc3d2e1f0L

#define K_00_19	0x5a827999L
#define K_20_39 0x6ed9eba1L
#define K_40_59 0x8f1bbcdcL
#define K_60_79 0xca62c1d6L

#ifndef NOPROTO
#  ifdef SHA1_ASM
void sha1_block_x86 (SHA1_ctx * c, register unsigned long *p, int num);
#    define sha1_block sha1_block_x86
#  else
void sha1_block (SHA1_ctx * c, register unsigned long *p, int num);
#  endif
#else
#  ifdef SHA1_ASM
void sha1_block_x86 ();
#    define sha1_block sha1_block_x86
#  else
void sha1_block ();
#  endif
#endif

#if defined(L_ENDIAN) && defined(SHA1_ASM)
#  define	M_c2nl		c2l
#  define	M_p_c2nl	p_c2l
#  define	M_c2nl_p	c2l_p
#  define	M_p_c2nl_p	p_c2l_p
#  define	M_nl2c		l2c
#else
#  define	M_c2nl		c2nl
#  define	M_p_c2nl	p_c2nl
#  define	M_c2nl_p	c2nl_p
#  define	M_p_c2nl_p	p_c2nl_p
#  define	M_nl2c		nl2c
#endif

void
SHA1_init (SHA1_ctx * c)
{
  c->h0 = INIT_DATA_h0;
  c->h1 = INIT_DATA_h1;
  c->h2 = INIT_DATA_h2;
  c->h3 = INIT_DATA_h3;
  c->h4 = INIT_DATA_h4;
  c->Nl = 0;
  c->Nh = 0;
  c->num = 0;
}

void
SHA1_update (SHA1_ctx * c, register unsigned char *data, unsigned long len)
{
  register ULONG *p;
  int ew, ec, sw, sc;
  ULONG l;

  if (len == 0)
    return;

  l = (c->Nl + (len << 3)) & 0xffffffffL;
  if (l < c->Nl)		/* overflow */
    c->Nh++;
  c->Nh += (len >> 29);
  c->Nl = l;

  if (c->num != 0)
    {
      p = c->data;
      sw = c->num >> 2;
      sc = c->num & 0x03;

      if ((c->num + len) >= SHA_CBLOCK)
	{
	  l = p[sw];
	  M_p_c2nl (data, l, sc);
	  p[sw++] = l;
	  for (; sw < SHA_LBLOCK; sw++)
	    {
	      M_c2nl (data, l);
	      p[sw] = l;
	    }
	  len -= (SHA_CBLOCK - c->num);

	  sha1_block (c, p, 64);
	  c->num = 0;
	  /* drop through and do the rest */
	}
      else
	{
	  c->num += (int) len;
	  if ((sc + len) < 4)	/* ugly, add char's to a word */
	    {
	      l = p[sw];
	      M_p_c2nl_p (data, l, sc, len);
	      p[sw] = l;
	    }
	  else
	    {
	      ew = (c->num >> 2);
	      ec = (c->num & 0x03);
	      l = p[sw];
	      M_p_c2nl (data, l, sc);
	      p[sw++] = l;
	      for (; sw < ew; sw++)
		{
		  M_c2nl (data, l);
		  p[sw] = l;
		}
	      if (ec)
		{
		  M_c2nl_p (data, l, ec);
		  p[sw] = l;
		}
	    }
	  return;
	}
    }
  /* We can only do the following code for assember, the reason
   * being that the sha1_block 'C' version changes the values
   * in the 'data' array.  The assember code avoids this and
   * copies it to a local array.  I should be able to do this for
   * the C version as well....
   */
#if 1
#if defined(B_ENDIAN) || defined(SHA1_ASM)
  if ((((unsigned int) data) % sizeof (ULONG)) == 0)
    {
      sw = len / SHA_CBLOCK;
      if (sw)
	{
	  sw *= SHA_CBLOCK;
	  sha1_block (c, (ULONG *) data, sw);
	  data += sw;
	  len -= sw;
	}
    }
#endif
#endif
  /* we now can process the input data in blocks of SHA_CBLOCK
   * chars and save the leftovers to c->data. */
  p = c->data;
  while (len >= SHA_CBLOCK)
    {
#if defined(B_ENDIAN) || defined(L_ENDIAN)
      if (p != (unsigned long *) data)
	memcpy (p, data, SHA_CBLOCK);
      data += SHA_CBLOCK;
#  ifdef L_ENDIAN
#    ifndef SHA1_ASM		/* Will not happen */
      for (sw = (SHA_LBLOCK / 4); sw; sw--)
	{
	  Endian_Reverse32 (p[0]);
	  Endian_Reverse32 (p[1]);
	  Endian_Reverse32 (p[2]);
	  Endian_Reverse32 (p[3]);
	  p += 4;
	}
      p = c->data;
#    endif
#  endif
#else
      for (sw = (SHA_BLOCK / 4); sw; sw--)
	{
	  M_c2nl (data, l);
	  *(p++) = l;
	  M_c2nl (data, l);
	  *(p++) = l;
	  M_c2nl (data, l);
	  *(p++) = l;
	  M_c2nl (data, l);
	  *(p++) = l;
	}
      p = c->data;
#endif
      sha1_block (c, p, 64);
      len -= SHA_CBLOCK;
    }
  ec = (int) len;
  c->num = ec;
  ew = (ec >> 2);
  ec &= 0x03;

  for (sw = 0; sw < ew; sw++)
    {
      M_c2nl (data, l);
      p[sw] = l;
    }
  M_c2nl_p (data, l, ec);
  p[sw] = l;
}

void
SHA1_transform (SHA1_ctx *c, unsigned char *b)
{
  ULONG p[16];
#ifndef B_ENDIAN
  ULONG *q;
  int i;
#endif

#if defined(B_ENDIAN) || defined(L_ENDIAN)
  memcpy (p, b, 64);
#ifdef L_ENDIAN
  q = p;
  for (i = (SHA_LBLOCK / 4); i; i--)
    {
      Endian_Reverse32 (q[0]);
      Endian_Reverse32 (q[1]);
      Endian_Reverse32 (q[2]);
      Endian_Reverse32 (q[3]);
      q += 4;
    }
#endif
#else
  q = p;
  for (i = (SHA_LBLOCK / 4); i; i--)
    {
      ULONG l;
      c2nl (b, l);
      *(q++) = l;
      c2nl (b, l);
      *(q++) = l;
      c2nl (b, l);
      *(q++) = l;
      c2nl (b, l);
      *(q++) = l;
    }
#endif
  sha1_block (c, p, 64);
}

#ifndef SHA1_ASM

void
sha1_block (SHA1_ctx *c, register unsigned long *W, int num)
{
  register ULONG A, B, C, D, E, T;
  ULONG X[16];

  A = c->h0;
  B = c->h1;
  C = c->h2;
  D = c->h3;
  E = c->h4;

  for (;;)
    {
      BODY_00_15 (0, A, B, C, D, E, T, W);
      BODY_00_15 (1, T, A, B, C, D, E, W);
      BODY_00_15 (2, E, T, A, B, C, D, W);
      BODY_00_15 (3, D, E, T, A, B, C, W);
      BODY_00_15 (4, C, D, E, T, A, B, W);
      BODY_00_15 (5, B, C, D, E, T, A, W);
      BODY_00_15 (6, A, B, C, D, E, T, W);
      BODY_00_15 (7, T, A, B, C, D, E, W);
      BODY_00_15 (8, E, T, A, B, C, D, W);
      BODY_00_15 (9, D, E, T, A, B, C, W);
      BODY_00_15 (10, C, D, E, T, A, B, W);
      BODY_00_15 (11, B, C, D, E, T, A, W);
      BODY_00_15 (12, A, B, C, D, E, T, W);
      BODY_00_15 (13, T, A, B, C, D, E, W);
      BODY_00_15 (14, E, T, A, B, C, D, W);
      BODY_00_15 (15, D, E, T, A, B, C, W);
      BODY_16_19 (16, C, D, E, T, A, B, W, W, W, W);
      BODY_16_19 (17, B, C, D, E, T, A, W, W, W, W);
      BODY_16_19 (18, A, B, C, D, E, T, W, W, W, W);
      BODY_16_19 (19, T, A, B, C, D, E, W, W, W, X);

      BODY_20_31 (20, E, T, A, B, C, D, W, W, W, X);
      BODY_20_31 (21, D, E, T, A, B, C, W, W, W, X);
      BODY_20_31 (22, C, D, E, T, A, B, W, W, W, X);
      BODY_20_31 (23, B, C, D, E, T, A, W, W, W, X);
      BODY_20_31 (24, A, B, C, D, E, T, W, W, X, X);
      BODY_20_31 (25, T, A, B, C, D, E, W, W, X, X);
      BODY_20_31 (26, E, T, A, B, C, D, W, W, X, X);
      BODY_20_31 (27, D, E, T, A, B, C, W, W, X, X);
      BODY_20_31 (28, C, D, E, T, A, B, W, W, X, X);
      BODY_20_31 (29, B, C, D, E, T, A, W, W, X, X);
      BODY_20_31 (30, A, B, C, D, E, T, W, X, X, X);
      BODY_20_31 (31, T, A, B, C, D, E, W, X, X, X);
      BODY_32_39 (32, E, T, A, B, C, D, X);
      BODY_32_39 (33, D, E, T, A, B, C, X);
      BODY_32_39 (34, C, D, E, T, A, B, X);
      BODY_32_39 (35, B, C, D, E, T, A, X);
      BODY_32_39 (36, A, B, C, D, E, T, X);
      BODY_32_39 (37, T, A, B, C, D, E, X);
      BODY_32_39 (38, E, T, A, B, C, D, X);
      BODY_32_39 (39, D, E, T, A, B, C, X);

      BODY_40_59 (40, C, D, E, T, A, B, X);
      BODY_40_59 (41, B, C, D, E, T, A, X);
      BODY_40_59 (42, A, B, C, D, E, T, X);
      BODY_40_59 (43, T, A, B, C, D, E, X);
      BODY_40_59 (44, E, T, A, B, C, D, X);
      BODY_40_59 (45, D, E, T, A, B, C, X);
      BODY_40_59 (46, C, D, E, T, A, B, X);
      BODY_40_59 (47, B, C, D, E, T, A, X);
      BODY_40_59 (48, A, B, C, D, E, T, X);
      BODY_40_59 (49, T, A, B, C, D, E, X);
      BODY_40_59 (50, E, T, A, B, C, D, X);
      BODY_40_59 (51, D, E, T, A, B, C, X);
      BODY_40_59 (52, C, D, E, T, A, B, X);
      BODY_40_59 (53, B, C, D, E, T, A, X);
      BODY_40_59 (54, A, B, C, D, E, T, X);
      BODY_40_59 (55, T, A, B, C, D, E, X);
      BODY_40_59 (56, E, T, A, B, C, D, X);
      BODY_40_59 (57, D, E, T, A, B, C, X);
      BODY_40_59 (58, C, D, E, T, A, B, X);
      BODY_40_59 (59, B, C, D, E, T, A, X);

      BODY_60_79 (60, A, B, C, D, E, T, X);
      BODY_60_79 (61, T, A, B, C, D, E, X);
      BODY_60_79 (62, E, T, A, B, C, D, X);
      BODY_60_79 (63, D, E, T, A, B, C, X);
      BODY_60_79 (64, C, D, E, T, A, B, X);
      BODY_60_79 (65, B, C, D, E, T, A, X);
      BODY_60_79 (66, A, B, C, D, E, T, X);
      BODY_60_79 (67, T, A, B, C, D, E, X);
      BODY_60_79 (68, E, T, A, B, C, D, X);
      BODY_60_79 (69, D, E, T, A, B, C, X);
      BODY_60_79 (70, C, D, E, T, A, B, X);
      BODY_60_79 (71, B, C, D, E, T, A, X);
      BODY_60_79 (72, A, B, C, D, E, T, X);
      BODY_60_79 (73, T, A, B, C, D, E, X);
      BODY_60_79 (74, E, T, A, B, C, D, X);
      BODY_60_79 (75, D, E, T, A, B, C, X);
      BODY_60_79 (76, C, D, E, T, A, B, X);
      BODY_60_79 (77, B, C, D, E, T, A, X);
      BODY_60_79 (78, A, B, C, D, E, T, X);
      BODY_60_79 (79, T, A, B, C, D, E, X);

      c->h0 = (c->h0 + E) & 0xffffffffL;
      c->h1 = (c->h1 + T) & 0xffffffffL;
      c->h2 = (c->h2 + A) & 0xffffffffL;
      c->h3 = (c->h3 + B) & 0xffffffffL;
      c->h4 = (c->h4 + C) & 0xffffffffL;

      num -= 64;
      if (num <= 0)
	break;

      A = c->h0;
      B = c->h1;
      C = c->h2;
      D = c->h3;
      E = c->h4;

      W += 16;
    }
}
#endif

void
SHA1_final (unsigned char *md, SHA1_ctx *c)
{
  register int i, j;
  register ULONG l;
  register ULONG *p;
  static unsigned char end[4] = { 0x80, 0x00, 0x00, 0x00 };
  unsigned char *cp = end;

  /* c->num should definitly have room for at least one more byte. */
  p = c->data;
  j = c->num;
  i = j >> 2;
#ifdef PURIFY
  if ((j & 0x03) == 0)
    p[i] = 0;
#endif
  l = p[i];
  M_p_c2nl (cp, l, j & 0x03);
  p[i] = l;
  i++;
  /* i is the next 'undefined word' */
  if (c->num >= SHA_LAST_BLOCK)
    {
      for (; i < SHA_LBLOCK; i++)
	p[i] = 0;
      sha1_block (c, p, 64);
      i = 0;
    }
  for (; i < (SHA_LBLOCK - 2); i++)
    p[i] = 0;
  p[SHA_LBLOCK - 2] = c->Nh;
  p[SHA_LBLOCK - 1] = c->Nl;
#if defined(L_ENDIAN) && defined(SHA1_ASM)
  Endian_Reverse32 (p[SHA_LBLOCK - 2]);
  Endian_Reverse32 (p[SHA_LBLOCK - 1]);
#endif
  sha1_block (c, p, 64);
  cp = md;
  l = c->h0;
  nl2c (l, cp);
  l = c->h1;
  nl2c (l, cp);
  l = c->h2;
  nl2c (l, cp);
  l = c->h3;
  nl2c (l, cp);
  l = c->h4;
  nl2c (l, cp);

  /* clear stuff, sha1_block may be leaving some stuff on the stack
   * but I'm not worried :-) */
  c->num = 0;
/*	memset((char *)&c,0,sizeof(c));*/
}