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1 /* NIST Secure Hash Algorithm */
2 /* heavily modified by Uwe Hollerbach <uh@alumni.caltech edu> */
3 /* from Peter C. Gutmann's implementation as found in */
4 /* Applied Cryptography by Bruce Schneier */
5 /* Further modifications to include the "UNRAVEL" stuff, below */
6
7 /* This code is in the public domain */
8
9 /* Modifications to dynamically determine endianness by Neil Winton */
10 /* $Id: sha_func.c,v 1.1.1.1 2001/04/12 18:07:04 ndwinton Exp $ */
11
12 #include <string.h>
13 #include "sha.h"
14
15 /* UNRAVEL should be fastest & biggest */
16 /* UNROLL_LOOPS should be just as big, but slightly slower */
17 /* both undefined should be smallest and slowest */
18
19 #define UNRAVEL
20 /* #define UNROLL_LOOPS */
21
22 /* NIST's proposed modification to SHA of 7/11/94 may be */
23 /* activated by defining USE_MODIFIED_SHA; leave it off for now */
24 #undef USE_MODIFIED_SHA
25
26 /* SHA f()-functions */
27
28 #define f1(x,y,z) ((x & y) | (~x & z))
29 #define f2(x,y,z) (x ^ y ^ z)
30 #define f3(x,y,z) ((x & y) | (x & z) | (y & z))
31 #define f4(x,y,z) (x ^ y ^ z)
32
33 /* SHA constants */
34
35 #define CONST1 0x5a827999L
36 #define CONST2 0x6ed9eba1L
37 #define CONST3 0x8f1bbcdcL
38 #define CONST4 0xca62c1d6L
39
40 /* 32-bit rotate */
41
42 #define ROT32(x,n) ((x << n) | (x >> (32 - n)))
43
44 /* the generic case, for when the overall rotation is not unraveled */
45
46 #define FG(n) \
47 T = ROT32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n; \
48 E = D; D = C; C = ROT32(B,30); B = A; A = T
49
50 /* specific cases, for when the overall rotation is unraveled */
51
52 #define FA(n) \
53 T = ROT32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n; B = ROT32(B,30)
54
55 #define FB(n) \
56 E = ROT32(T,5) + f##n(A,B,C) + D + *WP++ + CONST##n; A = ROT32(A,30)
57
58 #define FC(n) \
59 D = ROT32(E,5) + f##n(T,A,B) + C + *WP++ + CONST##n; T = ROT32(T,30)
60
61 #define FD(n) \
62 C = ROT32(D,5) + f##n(E,T,A) + B + *WP++ + CONST##n; E = ROT32(E,30)
63
64 #define FE(n) \
65 B = ROT32(C,5) + f##n(D,E,T) + A + *WP++ + CONST##n; D = ROT32(D,30)
66
67 #define FT(n) \
68 A = ROT32(B,5) + f##n(C,D,E) + T + *WP++ + CONST##n; C = ROT32(C,30)
69
70 /* do SHA transformation */
71
72 static void sha_transform(SHA_INFO *sha_info)
73 {
74 int i;
75 SHA_LONG T, A, B, C, D, E, W[80], *WP;
76
77 for (i = 0; i < 16; ++i) {
78 W[i] = sha_info->data[i];
79 }
80 for (i = 16; i < 80; ++i) {
81 W[i] = W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16];
82 #ifdef USE_MODIFIED_SHA
83 W[i] = ROT32(W[i], 1);
84 #endif /* USE_MODIFIED_SHA */
85 }
86 A = sha_info->digest[0];
87 B = sha_info->digest[1];
88 C = sha_info->digest[2];
89 D = sha_info->digest[3];
90 E = sha_info->digest[4];
91 WP = W;
92 #ifdef UNRAVEL
93 FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1); FC(1); FD(1);
94 FE(1); FT(1); FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1);
95 FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2); FE(2); FT(2);
96 FA(2); FB(2); FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2);
97 FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3); FA(3); FB(3);
98 FC(3); FD(3); FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3);
99 FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4); FC(4); FD(4);
100 FE(4); FT(4); FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4);
101 sha_info->digest[0] += E;
102 sha_info->digest[1] += T;
103 sha_info->digest[2] += A;
104 sha_info->digest[3] += B;
105 sha_info->digest[4] += C;
106 #else /* !UNRAVEL */
107 #ifdef UNROLL_LOOPS
108 FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);
109 FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);
110 FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);
111 FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);
112 FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);
113 FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);
114 FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);
115 FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);
116 #else /* !UNROLL_LOOPS */
117 for (i = 0; i < 20; ++i) { FG(1); }
118 for (i = 20; i < 40; ++i) { FG(2); }
119 for (i = 40; i < 60; ++i) { FG(3); }
120 for (i = 60; i < 80; ++i) { FG(4); }
121 #endif /* !UNROLL_LOOPS */
122 sha_info->digest[0] += A;
123 sha_info->digest[1] += B;
124 sha_info->digest[2] += C;
125 sha_info->digest[3] += D;
126 sha_info->digest[4] += E;
127 #endif /* !UNRAVEL */
128 }
129
130 /* change endianness of data if necessary */
131
132 static void maybe_byte_reverse(SHA_LONG *buffer, int count)
133 {
134 static int initialized = 0;
135 static int is_little_endian = 0;
136 int i;
137 SHA_LONG in;
138
139 if (!initialized)
140 {
141 union {
142 unsigned char bytes[4];
143 SHA_LONG integer;
144 } u;
145
146 /*
147 ** First call -- figure out endianness.
148 **
149 ** In theory we ought to worry about thread safety but in practice
150 ** even if two threads come in here simultaneously the worst
151 ** that will happen is that they will both end up figuring out
152 ** the endianness and will come to the same answer!
153 */
154
155 initialized++;
156
157 u.integer = 0x12345678;
158
159 is_little_endian = (u.bytes[0] == 0x78);
160 }
161
162 if (is_little_endian) {
163 count /= sizeof(SHA_LONG);
164 for (i = 0; i < count; ++i) {
165 in = *buffer;
166 *buffer++ = ((in << 24) & 0xff000000) | ((in << 8) & 0x00ff0000) |
167 ((in >> 8) & 0x0000ff00) | ((in >> 24) & 0x000000ff);
168 }
169 }
170 }
171
172 /* initialize the SHA digest */
173
174 void sha_init(SHA_INFO *sha_info)
175 {
176 sha_info->digest[0] = 0x67452301L;
177 sha_info->digest[1] = 0xefcdab89L;
178 sha_info->digest[2] = 0x98badcfeL;
179 sha_info->digest[3] = 0x10325476L;
180 sha_info->digest[4] = 0xc3d2e1f0L;
181 sha_info->count_lo = 0L;
182 sha_info->count_hi = 0L;
183 sha_info->local = 0;
184 }
185
186 /* update the SHA digest */
187
188 void sha_update(SHA_INFO *sha_info, SHA_BYTE *buffer, int count)
189 {
190 int i;
191
192 if ((sha_info->count_lo + ((SHA_LONG) count << 3)) < sha_info->count_lo) {
193 ++sha_info->count_hi;
194 }
195 sha_info->count_lo += (SHA_LONG) count << 3;
196 sha_info->count_hi += (SHA_LONG) count >> 29;
197 if (sha_info->local) {
198 i = SHA_BLOCKSIZE - sha_info->local;
199 if (i > count) {
200 i = count;
201 }
202 memcpy(((SHA_BYTE *) sha_info->data) + sha_info->local, buffer, i);
203 count -= i;
204 buffer += i;
205 sha_info->local += i;
206 if (sha_info->local == SHA_BLOCKSIZE) {
207 maybe_byte_reverse(sha_info->data, SHA_BLOCKSIZE);
208 sha_transform(sha_info);
209 } else {
210 return;
211 }
212 }
213 while (count >= SHA_BLOCKSIZE) {
214 memcpy(sha_info->data, buffer, SHA_BLOCKSIZE);
215 buffer += SHA_BLOCKSIZE;
216 count -= SHA_BLOCKSIZE;
217 maybe_byte_reverse(sha_info->data, SHA_BLOCKSIZE);
218 sha_transform(sha_info);
219 }
220 memcpy(sha_info->data, buffer, count);
221 sha_info->local = count;
222 }
223
224 /* finish computing the SHA digest */
225
226 void sha_final(SHA_INFO *sha_info)
227 {
228 int count;
229 SHA_LONG lo_bit_count, hi_bit_count;
230
231 lo_bit_count = sha_info->count_lo;
232 hi_bit_count = sha_info->count_hi;
233 count = (int) ((lo_bit_count >> 3) & 0x3f);
234 ((SHA_BYTE *) sha_info->data)[count++] = 0x80;
235 if (count > SHA_BLOCKSIZE - 8) {
236 memset(((SHA_BYTE *) sha_info->data) + count, 0, SHA_BLOCKSIZE - count);
237 maybe_byte_reverse(sha_info->data, SHA_BLOCKSIZE);
238 sha_transform(sha_info);
239 memset((SHA_BYTE *) sha_info->data, 0, SHA_BLOCKSIZE - 8);
240 } else {
241 memset(((SHA_BYTE *) sha_info->data) + count, 0,
242 SHA_BLOCKSIZE - 8 - count);
243 }
244 maybe_byte_reverse(sha_info->data, SHA_BLOCKSIZE);
245 sha_info->data[14] = hi_bit_count;
246 sha_info->data[15] = lo_bit_count;
247 sha_transform(sha_info);
248 }