sha1.c

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/*
SHA-1 in C
By Steve Reid <sreid@sea-to-sky.net>
100% Public Domain
 
-----------------
Modified 7/98
By James H. Brown <jbrown@burgoyne.com>
Still 100% Public Domain
 
-----------------
Adopted for s/qmail 2/2020
feh
Still 100% Public Domain; though requiring fehQlibs-14
 
*/
 
#include <string.h>
#include "sha1.h"
#include "byte.h"
 
// #define SHA1HANDSOFF
 
#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
 
/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
/* FIXME: can we do this in an endian-proof way? */
#ifndef WORDS_BIGENDIAN
#define blk0(i) (block->l[i] = (rol(block->l[i],24) & 0xFF00FF00) \
    | (rol(block->l[i],8) & 0x00FF00FF))
#else
#define blk0(i) block->l[i]
#endif
#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
    ^block->l[(i+2)&15]^block->l[i&15],1))
 
/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);
 
/* Hash a single 512-bit block. This is the core of the algorithm. */
 
void sha1_transform(uint32_t state[5],const uint8_t buffer[SHA1_BLOCKSIZE])
{
  uint32_t a, b, c, d, e;
  typedef union {
      uint8_t c[SHA1_BLOCKSIZE];
      uint32_t l[16];
  } CHAR64LONG16;
  CHAR64LONG16 *block;
 
#ifdef SHA1HANDSOFF
  static uint8_t workspace[SHA1_BLOCKSIZE];
 
  block = (CHAR64LONG16 *) workspace;
  byte_copy(block,SHA1_BLOCKSIZE,buffer);
#else
  block = (CHAR64LONG16 *) buffer;
#endif
 
  /* Copy context->state[] to working vars */
  a = state[0];
  b = state[1];
  c = state[2];
  d = state[3];
  e = state[4];
 
  /* 4 rounds of 20 operations each. Loop unrolled. */
  R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
  R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
  R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
  R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
  R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
  R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
  R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
  R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
  R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
  R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
  R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
  R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
  R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
  R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
  R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
  R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
  R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
  R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
  R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
  R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
 
  /* Add the working vars back into context.state[] */
  state[0] += a;
  state[1] += b;
  state[2] += c;
  state[3] += d;
  state[4] += e;
 
  /* Wipe variables */
  a = b = c = d = e = 0;
 
#ifdef SHA1HANDSOFF
        byte_zero(block,64);
#endif
}
 
/* SHA1Init - Initialize new context */
 
void sha1_init(sha1_ctx *context)
{
  /* SHA1 initialization constants */
  context->state[0] = 0x67452301;
  context->state[1] = 0xEFCDAB89;
  context->state[2] = 0x98BADCFE;
  context->state[3] = 0x10325476;
  context->state[4] = 0xC3D2E1F0;
  context->count[0] = context->count[1] = 0;
}
 
/* Run your data through this. */
 
void sha1_update(sha1_ctx *context,const uint8_t *data,uint32_t len)
{
  uint32_t i, j;
 
  j = (context->count[0] >> 3) & 63;
  if ((context->count[0] += len << 3) < (len << 3))
    context->count[1]++;
  context->count[1] += (len >> 29);
  if ((j + len) > 63) {
    byte_copy(&context->buffer[j],(i = 64 - j),data);
    sha1_transform(context->state,context->buffer);
    for (; i + 63 < len; i += 64) {
      sha1_transform(context->state,data + i);
    }
    j = 0;
  } else
    i = 0;
  byte_copy(&context->buffer[j],len - i,&data[i]);
}
 
/* Add padding and return the message digest. */
 
void sha1_final(uint8_t digest[SHA1_DIGESTSIZE],sha1_ctx *context)
{
  uint32_t i;
  uint8_t finalcount[8];
 
  for (i = 0; i < 8; i++) {
    finalcount[i] = (uint8_t)((context->count[(i >= 4 ? 0 : 1)]
      >> ((3 - (i & 3)) * 8)) & 255);        /* Endian independent */
  }
  sha1_update(context,(uint8_t *) "\200",1);
 
  while ((context->count[0] & 504) != 448)
    sha1_update(context,(uint8_t *) "\0",1);
  
  sha1_update(context,finalcount,8);        /* Should cause a SHA1_Transform() */
 
  for (i = 0; i < SHA1_DIGESTSIZE; i++) 
    digest[i] = (uint8_t) ((context->state[i >> 2] >> ((3 - (i & 3)) * 8)) & 255);
 
  /* Wipe variables */
  i = 0;
  byte_zero(context->buffer,64);
  byte_zero(context->state,20);
  byte_zero(context->count,8);
  byte_zero(finalcount,8);  
 
#ifdef SHA1HANDSOFF        /* make SHA1Transform overwrite its own static vars */
  sha1_transform(context->state,context->buffer);
#endif
}
 
void sha1_hash(char *hash,const char *str,uint32_t len)
{
  sha1_ctx context;
  int i;
 
  sha1_init(&context);
  for (i = 0; i < len; i++)
    sha1_update(&context,(uint8_t *)str + i,1);
 
  sha1_final((uint8_t *)hash,&context);
  hash[20] = '\0';
}