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Diffstat (limited to 'sha1.c')
| -rw-r--r-- | sha1.c | 399 |
1 files changed, 399 insertions, 0 deletions
@@ -0,0 +1,399 @@ +/*! + * \copy + * Copyright (c) 1998, 2009 Paul E. Jones <paulej@packetizer.com> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER + * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + */ + +/* + * Description: + * This file implements the Secure Hashing Standard as defined + * in FIPS PUB 180-1 published April 17, 1995. + * + * The Secure Hashing Standard, which uses the Secure Hashing + * Algorithm (SHA), produces a 160-bit message digest for a + * given data stream. In theory, it is highly improbable that + * two messages will produce the same message digest. Therefore, + * this algorithm can serve as a means of providing a "fingerprint" + * for a message. + * + * Portability Issues: + * SHA-1 is defined in terms of 32-bit "words". This code was + * written with the expectation that the processor has at least + * a 32-bit machine word size. If the machine word size is larger, + * the code should still function properly. One caveat to that + * is that the input functions taking characters and character + * arrays assume that only 8 bits of information are stored in each + * character. + * + * Caveats: + * SHA-1 is designed to work with messages less than 2^64 bits + * long. Although SHA-1 allows a message digest to be generated for + * messages of any number of bits less than 2^64, this + * implementation only works with messages with a length that is a + * multiple of the size of an 8-bit character. + * + */ + +#include "sha1.h" + +/* + * Define the circular shift macro + */ +#define SHA1CircularShift(bits,word) \ + ((((word) << (bits)) & 0xFFFFFFFF) | \ + ((word) >> (32-(bits)))) + +/* Function prototypes */ +void SHA1ProcessMessageBlock(SHA1Context *); +void SHA1PadMessage(SHA1Context *); + +/* + * SHA1Reset + * + * Description: + * This function will initialize the SHA1Context in preparation + * for computing a new message digest. + * + * Parameters: + * context: [in/out] + * The context to reset. + * + * Returns: + * Nothing. + * + * Comments: + * + */ +void SHA1Reset(SHA1Context *context) +{ + context->Length_Low = 0; + context->Length_High = 0; + context->Message_Block_Index = 0; + + context->Message_Digest[0] = 0x67452301; + context->Message_Digest[1] = 0xEFCDAB89; + context->Message_Digest[2] = 0x98BADCFE; + context->Message_Digest[3] = 0x10325476; + context->Message_Digest[4] = 0xC3D2E1F0; + + context->Computed = 0; + context->Corrupted = 0; +} + +/* + * SHA1Result + * + * Description: + * This function will return the 160-bit message digest into the + * digest array provided as a parameter. + * + * Parameters: + * context: [in/out] + * The context to use to calculate the SHA-1 hash. + * digest: [out] + * An array of characters where the digest is written. + * + * Returns: + * 1 if successful, 0 if it failed. + * + * Comments: + * + */ +int SHA1Result(SHA1Context *context, unsigned char *digest) +{ + int i; + + if (context->Corrupted) + { + return 0; + } + + if (!context->Computed) + { + SHA1PadMessage(context); + context->Computed = 1; + } + + for (i = 0; i < SHA_DIGEST_LENGTH; i++) + digest[i] = context->Message_Digest[i / 4] >> (8 * (3 - (i % 4))); + + return 1; +} + +/* + * SHA1Input + * + * Description: + * This function accepts an array of octets as the next portion of + * the message. + * + * Parameters: + * context: [in/out] + * The SHA-1 context to update + * message_array: [in] + * An array of characters representing the next portion of the + * message. + * length: [in] + * The length of the message in message_array + * + * Returns: + * Nothing. + * + * Comments: + * + */ +void SHA1Input( SHA1Context *context, + const unsigned char *message_array, + unsigned length) +{ + if (!length) + { + return; + } + + if (context->Computed || context->Corrupted) + { + context->Corrupted = 1; + return; + } + + while(length-- && !context->Corrupted) + { + context->Message_Block[context->Message_Block_Index++] = + (*message_array & 0xFF); + + context->Length_Low += 8; + /* Force it to 32 bits */ + context->Length_Low &= 0xFFFFFFFF; + if (context->Length_Low == 0) + { + context->Length_High++; + /* Force it to 32 bits */ + context->Length_High &= 0xFFFFFFFF; + if (context->Length_High == 0) + { + /* Message is too long */ + context->Corrupted = 1; + } + } + + if (context->Message_Block_Index == 64) + { + SHA1ProcessMessageBlock(context); + } + + message_array++; + } +} + +/* + * SHA1ProcessMessageBlock + * + * Description: + * This function will process the next 512 bits of the message + * stored in the Message_Block array. + * + * Parameters: + * None. + * + * Returns: + * Nothing. + * + * Comments: + * Many of the variable names in the SHAContext, especially the + * single character names, were used because those were the names + * used in the publication. + * + * + */ +void SHA1ProcessMessageBlock(SHA1Context *context) +{ + const unsigned K[] = /* Constants defined in SHA-1 */ + { + 0x5A827999, + 0x6ED9EBA1, + 0x8F1BBCDC, + 0xCA62C1D6 + }; + int t; /* Loop counter */ + unsigned temp; /* Temporary word value */ + unsigned W[80]; /* Word sequence */ + unsigned A, B, C, D, E; /* Word buffers */ + + /* + * Initialize the first 16 words in the array W + */ + for(t = 0; t < 16; t++) + { + W[t] = ((unsigned) context->Message_Block[t * 4]) << 24; + W[t] |= ((unsigned) context->Message_Block[t * 4 + 1]) << 16; + W[t] |= ((unsigned) context->Message_Block[t * 4 + 2]) << 8; + W[t] |= ((unsigned) context->Message_Block[t * 4 + 3]); + } + + for(t = 16; t < 80; t++) + { + W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]); + } + + A = context->Message_Digest[0]; + B = context->Message_Digest[1]; + C = context->Message_Digest[2]; + D = context->Message_Digest[3]; + E = context->Message_Digest[4]; + + for(t = 0; t < 20; t++) + { + temp = SHA1CircularShift(5,A) + + ((B & C) | ((~B) & D)) + E + W[t] + K[0]; + temp &= 0xFFFFFFFF; + E = D; + D = C; + C = SHA1CircularShift(30,B); + B = A; + A = temp; + } + + for(t = 20; t < 40; t++) + { + temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1]; + temp &= 0xFFFFFFFF; + E = D; + D = C; + C = SHA1CircularShift(30,B); + B = A; + A = temp; + } + + for(t = 40; t < 60; t++) + { + temp = SHA1CircularShift(5,A) + + ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2]; + temp &= 0xFFFFFFFF; + E = D; + D = C; + C = SHA1CircularShift(30,B); + B = A; + A = temp; + } + + for(t = 60; t < 80; t++) + { + temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3]; + temp &= 0xFFFFFFFF; + E = D; + D = C; + C = SHA1CircularShift(30,B); + B = A; + A = temp; + } + + context->Message_Digest[0] = + (context->Message_Digest[0] + A) & 0xFFFFFFFF; + context->Message_Digest[1] = + (context->Message_Digest[1] + B) & 0xFFFFFFFF; + context->Message_Digest[2] = + (context->Message_Digest[2] + C) & 0xFFFFFFFF; + context->Message_Digest[3] = + (context->Message_Digest[3] + D) & 0xFFFFFFFF; + context->Message_Digest[4] = + (context->Message_Digest[4] + E) & 0xFFFFFFFF; + + context->Message_Block_Index = 0; +} + +/* + * SHA1PadMessage + * + * Description: + * According to the standard, the message must be padded to an even + * 512 bits. The first padding bit must be a '1'. The last 64 + * bits represent the length of the original message. All bits in + * between should be 0. This function will pad the message + * according to those rules by filling the Message_Block array + * accordingly. It will also call SHA1ProcessMessageBlock() + * appropriately. When it returns, it can be assumed that the + * message digest has been computed. + * + * Parameters: + * context: [in/out] + * The context to pad + * + * Returns: + * Nothing. + * + * Comments: + * + */ +void SHA1PadMessage(SHA1Context *context) +{ + /* + * Check to see if the current message block is too small to hold + * the initial padding bits and length. If so, we will pad the + * block, process it, and then continue padding into a second + * block. + */ + if (context->Message_Block_Index > 55) + { + context->Message_Block[context->Message_Block_Index++] = 0x80; + while(context->Message_Block_Index < 64) + { + context->Message_Block[context->Message_Block_Index++] = 0; + } + + SHA1ProcessMessageBlock(context); + + while(context->Message_Block_Index < 56) + { + context->Message_Block[context->Message_Block_Index++] = 0; + } + } + else + { + context->Message_Block[context->Message_Block_Index++] = 0x80; + while(context->Message_Block_Index < 56) + { + context->Message_Block[context->Message_Block_Index++] = 0; + } + } + + /* + * Store the message length as the last 8 octets + */ + context->Message_Block[56] = (context->Length_High >> 24) & 0xFF; + context->Message_Block[57] = (context->Length_High >> 16) & 0xFF; + context->Message_Block[58] = (context->Length_High >> 8) & 0xFF; + context->Message_Block[59] = (context->Length_High) & 0xFF; + context->Message_Block[60] = (context->Length_Low >> 24) & 0xFF; + context->Message_Block[61] = (context->Length_Low >> 16) & 0xFF; + context->Message_Block[62] = (context->Length_Low >> 8) & 0xFF; + context->Message_Block[63] = (context->Length_Low) & 0xFF; + + SHA1ProcessMessageBlock(context); +} |