2 * Copyright (c) 2007, Cameron Rich
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
9 * * Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 * * Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
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32 * SHA1 implementation - as defined in FIPS PUB 180-1 published April 17, 1995.
33 * This code was originally taken from RFC3174
40 * Define the SHA1 circular left shift macro
42 #define SHA1CircularShift(bits,word) \
43 (((word) << (bits)) | ((word) >> (32-(bits))))
45 /* ----- static functions ----- */
46 static void SHA1PadMessage(SHA1_CTX *ctx);
47 static void SHA1ProcessMessageBlock(SHA1_CTX *ctx);
50 * Initialize the SHA1 context
52 void SHA1_Init(SHA1_CTX *ctx)
56 ctx->Message_Block_Index = 0;
57 ctx->Intermediate_Hash[0] = 0x67452301;
58 ctx->Intermediate_Hash[1] = 0xEFCDAB89;
59 ctx->Intermediate_Hash[2] = 0x98BADCFE;
60 ctx->Intermediate_Hash[3] = 0x10325476;
61 ctx->Intermediate_Hash[4] = 0xC3D2E1F0;
65 * Accepts an array of octets as the next portion of the message.
67 void SHA1_Update(SHA1_CTX *ctx, const uint8_t *msg, int len)
71 ctx->Message_Block[ctx->Message_Block_Index++] = (*msg & 0xFF);
74 if (ctx->Length_Low == 0)
77 if (ctx->Message_Block_Index == 64)
78 SHA1ProcessMessageBlock(ctx);
85 * Return the 160-bit message digest into the user's array
87 void SHA1_Final(uint8_t *digest, SHA1_CTX *ctx)
92 memset(ctx->Message_Block, 0, 64);
93 ctx->Length_Low = 0; /* and clear length */
96 for (i = 0; i < SHA1_SIZE; i++)
98 digest[i] = ctx->Intermediate_Hash[i>>2] >> 8 * ( 3 - ( i & 0x03 ) );
103 * Process the next 512 bits of the message stored in the array.
105 static void SHA1ProcessMessageBlock(SHA1_CTX *ctx)
107 const uint32_t K[] = { /* Constants defined in SHA-1 */
113 int t; /* Loop counter */
114 uint32_t temp; /* Temporary word value */
115 uint32_t W[80]; /* Word sequence */
116 uint32_t A, B, C, D, E; /* Word buffers */
119 * Initialize the first 16 words in the array W
121 for (t = 0; t < 16; t++)
123 W[t] = ctx->Message_Block[t * 4] << 24;
124 W[t] |= ctx->Message_Block[t * 4 + 1] << 16;
125 W[t] |= ctx->Message_Block[t * 4 + 2] << 8;
126 W[t] |= ctx->Message_Block[t * 4 + 3];
129 for (t = 16; t < 80; t++)
131 W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
134 A = ctx->Intermediate_Hash[0];
135 B = ctx->Intermediate_Hash[1];
136 C = ctx->Intermediate_Hash[2];
137 D = ctx->Intermediate_Hash[3];
138 E = ctx->Intermediate_Hash[4];
140 for (t = 0; t < 20; t++)
142 temp = SHA1CircularShift(5,A) +
143 ((B & C) | ((~B) & D)) + E + W[t] + K[0];
146 C = SHA1CircularShift(30,B);
152 for (t = 20; t < 40; t++)
154 temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1];
157 C = SHA1CircularShift(30,B);
162 for (t = 40; t < 60; t++)
164 temp = SHA1CircularShift(5,A) +
165 ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
168 C = SHA1CircularShift(30,B);
173 for (t = 60; t < 80; t++)
175 temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3];
178 C = SHA1CircularShift(30,B);
183 ctx->Intermediate_Hash[0] += A;
184 ctx->Intermediate_Hash[1] += B;
185 ctx->Intermediate_Hash[2] += C;
186 ctx->Intermediate_Hash[3] += D;
187 ctx->Intermediate_Hash[4] += E;
188 ctx->Message_Block_Index = 0;
192 * According to the standard, the message must be padded to an even
193 * 512 bits. The first padding bit must be a '1'. The last 64
194 * bits represent the length of the original message. All bits in
195 * between should be 0. This function will pad the message
196 * according to those rules by filling the Message_Block array
197 * accordingly. It will also call the ProcessMessageBlock function
198 * provided appropriately. When it returns, it can be assumed that
199 * the message digest has been computed.
201 * @param ctx [in, out] The SHA1 context
203 static void SHA1PadMessage(SHA1_CTX *ctx)
206 * Check to see if the current message block is too small to hold
207 * the initial padding bits and length. If so, we will pad the
208 * block, process it, and then continue padding into a second
211 if (ctx->Message_Block_Index > 55)
213 ctx->Message_Block[ctx->Message_Block_Index++] = 0x80;
214 while(ctx->Message_Block_Index < 64)
216 ctx->Message_Block[ctx->Message_Block_Index++] = 0;
219 SHA1ProcessMessageBlock(ctx);
221 while (ctx->Message_Block_Index < 56)
223 ctx->Message_Block[ctx->Message_Block_Index++] = 0;
228 ctx->Message_Block[ctx->Message_Block_Index++] = 0x80;
229 while(ctx->Message_Block_Index < 56)
232 ctx->Message_Block[ctx->Message_Block_Index++] = 0;
237 * Store the message length as the last 8 octets
239 ctx->Message_Block[56] = ctx->Length_High >> 24;
240 ctx->Message_Block[57] = ctx->Length_High >> 16;
241 ctx->Message_Block[58] = ctx->Length_High >> 8;
242 ctx->Message_Block[59] = ctx->Length_High;
243 ctx->Message_Block[60] = ctx->Length_Low >> 24;
244 ctx->Message_Block[61] = ctx->Length_Low >> 16;
245 ctx->Message_Block[62] = ctx->Length_Low >> 8;
246 ctx->Message_Block[63] = ctx->Length_Low;
247 SHA1ProcessMessageBlock(ctx);