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/* NIST Secure Hash Algorithm */
/* heavily modified by Uwe Hollerbach <uh@alumni.caltech edu> */
/* from Peter C. Gutmann's implementation as found in */
/* Applied Cryptography by Bruce Schneier */
/* Further modifications to include the "UNRAVEL" stuff, below */
/* This code is in the public domain */
#include "edsio.h"
#include <string.h>
#define SHA_BLOCKSIZE 64
#define SHA_DIGESTSIZE 20
/* UNRAVEL should be fastest & biggest */
/* UNROLL_LOOPS should be just as big, but slightly slower */
/* both undefined should be smallest and slowest */
#define UNRAVEL
/* #define UNROLL_LOOPS */
/* by default, compile for little-endian machines (Intel, Vax) */
/* change for big-endian machines; for machines which are neither, */
/* you will need to change the definition of maybe_byte_reverse */
#ifndef WORDS_BIGENDIAN /* from config.h */
#define SHA_LITTLE_ENDIAN
#endif
/* NIST's proposed modification to SHA of 7/11/94 may be */
/* activated by defining USE_MODIFIED_SHA; leave it off for now */
#undef USE_MODIFIED_SHA
/* SHA f()-functions */
#define f1(x,y,z) ((x & y) | (~x & z))
#define f2(x,y,z) (x ^ y ^ z)
#define f3(x,y,z) ((x & y) | (x & z) | (y & z))
#define f4(x,y,z) (x ^ y ^ z)
/* SHA constants */
#define CONST1 0x5a827999L
#define CONST2 0x6ed9eba1L
#define CONST3 0x8f1bbcdcL
#define CONST4 0xca62c1d6L
/* 32-bit rotate */
#define ROT32(x,n) ((x << n) | (x >> (32 - n)))
/* the generic case, for when the overall rotation is not unraveled */
#define FG(n) \
T = ROT32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n; \
E = D; D = C; C = ROT32(B,30); B = A; A = T
/* specific cases, for when the overall rotation is unraveled */
#define FA(n) \
T = ROT32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n; B = ROT32(B,30)
#define FB(n) \
E = ROT32(T,5) + f##n(A,B,C) + D + *WP++ + CONST##n; A = ROT32(A,30)
#define FC(n) \
D = ROT32(E,5) + f##n(T,A,B) + C + *WP++ + CONST##n; T = ROT32(T,30)
#define FD(n) \
C = ROT32(D,5) + f##n(E,T,A) + B + *WP++ + CONST##n; E = ROT32(E,30)
#define FE(n) \
B = ROT32(C,5) + f##n(D,E,T) + A + *WP++ + CONST##n; D = ROT32(D,30)
#define FT(n) \
A = ROT32(B,5) + f##n(C,D,E) + T + *WP++ + CONST##n; C = ROT32(C,30)
/* do SHA transformation */
static void sha_transform(EdsioSHACtx *ctx)
{
int i;
guint32 T, A, B, C, D, E, W[80], *WP;
for (i = 0; i < 16; ++i) {
W[i] = ctx->data[i];
}
for (i = 16; i < 80; ++i) {
W[i] = W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16];
#ifdef USE_MODIFIED_SHA
W[i] = ROT32(W[i], 1);
#endif /* USE_MODIFIED_SHA */
}
A = ctx->digest[0];
B = ctx->digest[1];
C = ctx->digest[2];
D = ctx->digest[3];
E = ctx->digest[4];
WP = W;
#ifdef UNRAVEL
FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1); FC(1); FD(1);
FE(1); FT(1); FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1);
FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2); FE(2); FT(2);
FA(2); FB(2); FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2);
FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3); FA(3); FB(3);
FC(3); FD(3); FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3);
FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4); FC(4); FD(4);
FE(4); FT(4); FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4);
ctx->digest[0] += E;
ctx->digest[1] += T;
ctx->digest[2] += A;
ctx->digest[3] += B;
ctx->digest[4] += C;
#else /* !UNRAVEL */
#ifdef UNROLL_LOOPS
FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);
FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);
FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);
FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);
FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);
FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);
FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);
FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);
#else /* !UNROLL_LOOPS */
for (i = 0; i < 20; ++i) { FG(1); }
for (i = 20; i < 40; ++i) { FG(2); }
for (i = 40; i < 60; ++i) { FG(3); }
for (i = 60; i < 80; ++i) { FG(4); }
#endif /* !UNROLL_LOOPS */
ctx->digest[0] += A;
ctx->digest[1] += B;
ctx->digest[2] += C;
ctx->digest[3] += D;
ctx->digest[4] += E;
#endif /* !UNRAVEL */
}
#ifdef SHA_LITTLE_ENDIAN
/* change endianness of data */
static void maybe_byte_reverse(guint32 *buffer, int count)
{
int i;
guint32 in;
count /= sizeof(guint32);
for (i = 0; i < count; ++i) {
in = *buffer;
*buffer++ = ((in << 24) & 0xff000000) | ((in << 8) & 0x00ff0000) |
((in >> 8) & 0x0000ff00) | ((in >> 24) & 0x000000ff);
}
}
#else /* !SHA_LITTLE_ENDIAN */
#define maybe_byte_reverse(a,b) /* do nothing */
#endif /* SHA_LITTLE_ENDIAN */
/* initialize the SHA digest */
void edsio_sha_init(EdsioSHACtx *ctx)
{
ctx->digest[0] = 0x67452301L;
ctx->digest[1] = 0xefcdab89L;
ctx->digest[2] = 0x98badcfeL;
ctx->digest[3] = 0x10325476L;
ctx->digest[4] = 0xc3d2e1f0L;
ctx->count_lo = 0L;
ctx->count_hi = 0L;
ctx->local = 0;
}
/* update the SHA digest */
void edsio_sha_update(EdsioSHACtx *ctx, const guint8 *buffer, guint count)
{
int i;
if ((ctx->count_lo + ((guint32) count << 3)) < ctx->count_lo) {
++ctx->count_hi;
}
ctx->count_lo += (guint32) count << 3;
ctx->count_hi += (guint32) count >> 29;
if (ctx->local) {
i = SHA_BLOCKSIZE - ctx->local;
if (i > count) {
i = count;
}
memcpy(((guint8 *) ctx->data) + ctx->local, buffer, i);
count -= i;
buffer += i;
ctx->local += i;
if (ctx->local == SHA_BLOCKSIZE) {
maybe_byte_reverse(ctx->data, SHA_BLOCKSIZE);
sha_transform(ctx);
} else {
return;
}
}
while (count >= SHA_BLOCKSIZE) {
memcpy(ctx->data, buffer, SHA_BLOCKSIZE);
buffer += SHA_BLOCKSIZE;
count -= SHA_BLOCKSIZE;
maybe_byte_reverse(ctx->data, SHA_BLOCKSIZE);
sha_transform(ctx);
}
memcpy(ctx->data, buffer, count);
ctx->local = count;
}
/* finish computing the SHA digest */
void edsio_sha_final(guint8* digest, EdsioSHACtx *ctx)
{
int count;
guint32 lo_bit_count, hi_bit_count;
lo_bit_count = ctx->count_lo;
hi_bit_count = ctx->count_hi;
count = (int) ((lo_bit_count >> 3) & 0x3f);
((guint8 *) ctx->data)[count++] = 0x80;
if (count > SHA_BLOCKSIZE - 8) {
memset(((guint8 *) ctx->data) + count, 0, SHA_BLOCKSIZE - count);
maybe_byte_reverse(ctx->data, SHA_BLOCKSIZE);
sha_transform(ctx);
memset((guint8 *) ctx->data, 0, SHA_BLOCKSIZE - 8);
} else {
memset(((guint8 *) ctx->data) + count, 0,
SHA_BLOCKSIZE - 8 - count);
}
maybe_byte_reverse(ctx->data, SHA_BLOCKSIZE);
ctx->data[14] = hi_bit_count;
ctx->data[15] = lo_bit_count;
sha_transform(ctx);
memcpy (digest, ctx->digest, 20);
}
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