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064af421 BP |
1 | /* |
2 | * sha1.c | |
3 | * | |
4 | * Description: | |
5 | * This file implements the Secure Hashing Algorithm 1 as | |
6 | * defined in FIPS PUB 180-1 published April 17, 1995. | |
7 | * | |
8 | * The SHA-1, produces a 160-bit message digest for a given | |
9 | * data stream. It should take about 2**n steps to find a | |
10 | * message with the same digest as a given message and | |
11 | * 2**(n/2) to find any two messages with the same digest, | |
12 | * when n is the digest size in bits. Therefore, this | |
13 | * algorithm can serve as a means of providing a | |
14 | * "fingerprint" for a message. | |
15 | * | |
16 | * Portability Issues: | |
17 | * SHA-1 is defined in terms of 32-bit "words". This code | |
18 | * uses <stdint.h> (included via "sha1.h" to define 32 and 8 | |
19 | * bit unsigned integer types. If your C compiler does not | |
20 | * support 32 bit unsigned integers, this code is not | |
21 | * appropriate. | |
22 | * | |
23 | * Caveats: | |
24 | * SHA-1 is designed to work with messages less than 2^64 bits | |
25 | * long. Although SHA-1 allows a message digest to be generated | |
26 | * for messages of any number of bits less than 2^64, this | |
27 | * implementation only works with messages with a length that is | |
28 | * a multiple of the size of an 8-bit character. | |
29 | * | |
30 | */ | |
31 | ||
32 | #include "sha1.h" | |
33 | ||
34 | /* | |
35 | * Define the SHA1 circular left shift macro | |
36 | */ | |
37 | #define SHA1CircularShift(bits,word) \ | |
38 | (((word) << (bits)) | ((word) >> (32-(bits)))) | |
39 | ||
40 | /* Local Function Prototyptes */ | |
41 | void SHA1PadMessage(SHA1Context *); | |
42 | void SHA1ProcessMessageBlock(SHA1Context *); | |
43 | ||
44 | /* | |
45 | * SHA1Reset | |
46 | * | |
47 | * Description: | |
48 | * This function will initialize the SHA1Context in preparation | |
49 | * for computing a new SHA1 message digest. | |
50 | * | |
51 | * Parameters: | |
52 | * context: [in/out] | |
53 | * The context to reset. | |
54 | * | |
55 | * Returns: | |
56 | * sha Error Code. | |
57 | * | |
58 | */ | |
59 | int SHA1Reset(SHA1Context *context) | |
60 | { | |
61 | if (!context) | |
62 | { | |
63 | return shaNull; | |
64 | } | |
65 | ||
66 | context->Length_Low = 0; | |
67 | context->Length_High = 0; | |
68 | context->Message_Block_Index = 0; | |
69 | ||
70 | context->Intermediate_Hash[0] = 0x67452301; | |
71 | context->Intermediate_Hash[1] = 0xEFCDAB89; | |
72 | context->Intermediate_Hash[2] = 0x98BADCFE; | |
73 | context->Intermediate_Hash[3] = 0x10325476; | |
74 | context->Intermediate_Hash[4] = 0xC3D2E1F0; | |
75 | ||
76 | context->Computed = 0; | |
77 | context->Corrupted = 0; | |
78 | ||
79 | return shaSuccess; | |
80 | } | |
81 | ||
82 | /* | |
83 | * SHA1Result | |
84 | * | |
85 | * Description: | |
86 | * This function will return the 160-bit message digest into the | |
87 | * Message_Digest array provided by the caller. | |
88 | * NOTE: The first octet of hash is stored in the 0th element, | |
89 | * the last octet of hash in the 19th element. | |
90 | * | |
91 | * Parameters: | |
92 | * context: [in/out] | |
93 | * The context to use to calculate the SHA-1 hash. | |
94 | * Message_Digest: [out] | |
95 | * Where the digest is returned. | |
96 | * | |
97 | * Returns: | |
98 | * sha Error Code. | |
99 | * | |
100 | */ | |
101 | int SHA1Result( SHA1Context *context, | |
102 | uint8_t Message_Digest[SHA1HashSize]) | |
103 | { | |
104 | int i; | |
105 | ||
106 | if (!context || !Message_Digest) | |
107 | { | |
108 | return shaNull; | |
109 | } | |
110 | ||
111 | if (context->Corrupted) | |
112 | { | |
113 | return context->Corrupted; | |
114 | } | |
115 | ||
116 | if (!context->Computed) | |
117 | { | |
118 | SHA1PadMessage(context); | |
119 | for(i=0; i<64; ++i) | |
120 | { | |
121 | /* message may be sensitive, clear it out */ | |
122 | context->Message_Block[i] = 0; | |
123 | } | |
124 | context->Length_Low = 0; /* and clear length */ | |
125 | context->Length_High = 0; | |
126 | context->Computed = 1; | |
127 | } | |
128 | ||
129 | for(i = 0; i < SHA1HashSize; ++i) | |
130 | { | |
131 | Message_Digest[i] = context->Intermediate_Hash[i>>2] | |
132 | >> 8 * ( 3 - ( i & 0x03 ) ); | |
133 | } | |
134 | ||
135 | return shaSuccess; | |
136 | } | |
137 | ||
138 | /* | |
139 | * SHA1Input | |
140 | * | |
141 | * Description: | |
142 | * This function accepts an array of octets as the next portion | |
143 | * of the message. | |
144 | * | |
145 | * Parameters: | |
146 | * context: [in/out] | |
147 | * The SHA context to update | |
148 | * message_array: [in] | |
149 | * An array of characters representing the next portion of | |
150 | * the message. | |
151 | * length: [in] | |
152 | * The length of the message in message_array | |
153 | * | |
154 | * Returns: | |
155 | * sha Error Code. | |
156 | * | |
157 | */ | |
158 | int SHA1Input( SHA1Context *context, | |
159 | const uint8_t *message_array, | |
160 | unsigned length) | |
161 | { | |
162 | if (!length) | |
163 | { | |
164 | return shaSuccess; | |
165 | } | |
166 | ||
167 | if (!context || !message_array) | |
168 | { | |
169 | return shaNull; | |
170 | } | |
171 | ||
172 | if (context->Computed) | |
173 | { | |
174 | context->Corrupted = shaStateError; | |
175 | return shaStateError; | |
176 | } | |
177 | ||
178 | if (context->Corrupted) | |
179 | { | |
180 | return context->Corrupted; | |
181 | } | |
182 | while(length-- && !context->Corrupted) | |
183 | { | |
184 | context->Message_Block[context->Message_Block_Index++] = | |
185 | (*message_array & 0xFF); | |
186 | ||
187 | context->Length_Low += 8; | |
188 | if (context->Length_Low == 0) | |
189 | { | |
190 | context->Length_High++; | |
191 | if (context->Length_High == 0) | |
192 | { | |
193 | /* Message is too long */ | |
194 | context->Corrupted = 1; | |
195 | } | |
196 | } | |
197 | ||
198 | if (context->Message_Block_Index == 64) | |
199 | { | |
200 | SHA1ProcessMessageBlock(context); | |
201 | } | |
202 | ||
203 | message_array++; | |
204 | } | |
205 | ||
206 | return shaSuccess; | |
207 | } | |
208 | ||
209 | /* | |
210 | * SHA1ProcessMessageBlock | |
211 | * | |
212 | * Description: | |
213 | * This function will process the next 512 bits of the message | |
214 | * stored in the Message_Block array. | |
215 | * | |
216 | * Parameters: | |
217 | * None. | |
218 | * | |
219 | * Returns: | |
220 | * Nothing. | |
221 | * | |
222 | * Comments: | |
223 | * Many of the variable names in this code, especially the | |
224 | * single character names, were used because those were the | |
225 | * names used in the publication. | |
226 | * | |
227 | * | |
228 | */ | |
229 | void SHA1ProcessMessageBlock(SHA1Context *context) | |
230 | { | |
231 | const uint32_t K[] = { /* Constants defined in SHA-1 */ | |
232 | 0x5A827999, | |
233 | 0x6ED9EBA1, | |
234 | 0x8F1BBCDC, | |
235 | 0xCA62C1D6 | |
236 | }; | |
237 | int t; /* Loop counter */ | |
238 | uint32_t temp; /* Temporary word value */ | |
239 | uint32_t W[80]; /* Word sequence */ | |
240 | uint32_t A, B, C, D, E; /* Word buffers */ | |
241 | ||
242 | /* | |
243 | * Initialize the first 16 words in the array W | |
244 | */ | |
245 | for(t = 0; t < 16; t++) | |
246 | { | |
247 | W[t] = context->Message_Block[t * 4] << 24; | |
248 | W[t] |= context->Message_Block[t * 4 + 1] << 16; | |
249 | W[t] |= context->Message_Block[t * 4 + 2] << 8; | |
250 | W[t] |= context->Message_Block[t * 4 + 3]; | |
251 | } | |
252 | ||
253 | for(t = 16; t < 80; t++) | |
254 | { | |
255 | W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]); | |
256 | } | |
257 | ||
258 | A = context->Intermediate_Hash[0]; | |
259 | B = context->Intermediate_Hash[1]; | |
260 | C = context->Intermediate_Hash[2]; | |
261 | D = context->Intermediate_Hash[3]; | |
262 | E = context->Intermediate_Hash[4]; | |
263 | ||
264 | for(t = 0; t < 20; t++) | |
265 | { | |
266 | temp = SHA1CircularShift(5,A) + | |
267 | ((B & C) | ((~B) & D)) + E + W[t] + K[0]; | |
268 | E = D; | |
269 | D = C; | |
270 | C = SHA1CircularShift(30,B); | |
271 | B = A; | |
272 | A = temp; | |
273 | } | |
274 | ||
275 | for(t = 20; t < 40; t++) | |
276 | { | |
277 | temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1]; | |
278 | E = D; | |
279 | D = C; | |
280 | C = SHA1CircularShift(30,B); | |
281 | B = A; | |
282 | A = temp; | |
283 | } | |
284 | ||
285 | for(t = 40; t < 60; t++) | |
286 | { | |
287 | temp = SHA1CircularShift(5,A) + | |
288 | ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2]; | |
289 | E = D; | |
290 | D = C; | |
291 | C = SHA1CircularShift(30,B); | |
292 | B = A; | |
293 | A = temp; | |
294 | } | |
295 | ||
296 | for(t = 60; t < 80; t++) | |
297 | { | |
298 | temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3]; | |
299 | E = D; | |
300 | D = C; | |
301 | C = SHA1CircularShift(30,B); | |
302 | B = A; | |
303 | A = temp; | |
304 | } | |
305 | ||
306 | context->Intermediate_Hash[0] += A; | |
307 | context->Intermediate_Hash[1] += B; | |
308 | context->Intermediate_Hash[2] += C; | |
309 | context->Intermediate_Hash[3] += D; | |
310 | context->Intermediate_Hash[4] += E; | |
311 | ||
312 | context->Message_Block_Index = 0; | |
313 | } | |
314 | ||
315 | ||
316 | /* | |
317 | * SHA1PadMessage | |
318 | * | |
319 | * Description: | |
320 | * According to the standard, the message must be padded to an even | |
321 | * 512 bits. The first padding bit must be a '1'. The last 64 | |
322 | * bits represent the length of the original message. All bits in | |
323 | * between should be 0. This function will pad the message | |
324 | * according to those rules by filling the Message_Block array | |
325 | * accordingly. It will also call the ProcessMessageBlock function | |
326 | * provided appropriately. When it returns, it can be assumed that | |
327 | * the message digest has been computed. | |
328 | * | |
329 | * Parameters: | |
330 | * context: [in/out] | |
331 | * The context to pad | |
332 | * ProcessMessageBlock: [in] | |
333 | * The appropriate SHA*ProcessMessageBlock function | |
334 | * Returns: | |
335 | * Nothing. | |
336 | * | |
337 | */ | |
338 | ||
339 | void SHA1PadMessage(SHA1Context *context) | |
340 | { | |
341 | /* | |
342 | * Check to see if the current message block is too small to hold | |
343 | * the initial padding bits and length. If so, we will pad the | |
344 | * block, process it, and then continue padding into a second | |
345 | * block. | |
346 | */ | |
347 | if (context->Message_Block_Index > 55) | |
348 | { | |
349 | context->Message_Block[context->Message_Block_Index++] = 0x80; | |
350 | while(context->Message_Block_Index < 64) | |
351 | { | |
352 | context->Message_Block[context->Message_Block_Index++] = 0; | |
353 | } | |
354 | ||
355 | SHA1ProcessMessageBlock(context); | |
356 | ||
357 | while(context->Message_Block_Index < 56) | |
358 | { | |
359 | context->Message_Block[context->Message_Block_Index++] = 0; | |
360 | } | |
361 | } | |
362 | else | |
363 | { | |
364 | context->Message_Block[context->Message_Block_Index++] = 0x80; | |
365 | while(context->Message_Block_Index < 56) | |
366 | { | |
367 | context->Message_Block[context->Message_Block_Index++] = 0; | |
368 | } | |
369 | } | |
370 | ||
371 | /* | |
372 | * Store the message length as the last 8 octets | |
373 | */ | |
374 | context->Message_Block[56] = context->Length_High >> 24; | |
375 | context->Message_Block[57] = context->Length_High >> 16; | |
376 | context->Message_Block[58] = context->Length_High >> 8; | |
377 | context->Message_Block[59] = context->Length_High; | |
378 | context->Message_Block[60] = context->Length_Low >> 24; | |
379 | context->Message_Block[61] = context->Length_Low >> 16; | |
380 | context->Message_Block[62] = context->Length_Low >> 8; | |
381 | context->Message_Block[63] = context->Length_Low; | |
382 | ||
383 | SHA1ProcessMessageBlock(context); | |
384 | } | |
385 | ||
386 | void | |
387 | SHA1Bytes(const void *data, unsigned int n, | |
388 | uint8_t Message_Digest[SHA1HashSize]) | |
389 | { | |
390 | SHA1Context ctx; | |
391 | SHA1Reset(&ctx); | |
392 | SHA1Input(&ctx, data, n); | |
393 | SHA1Result(&ctx, Message_Digest); | |
394 | } |