diff options
Diffstat (limited to 'crypto/sha1.c')
| -rw-r--r-- | crypto/sha1.c | 518 |
1 files changed, 518 insertions, 0 deletions
diff --git a/crypto/sha1.c b/crypto/sha1.c new file mode 100644 index 0000000..ea2bf70 --- /dev/null +++ b/crypto/sha1.c @@ -0,0 +1,518 @@ +/* + * sha1.c + * + * Description: + * This file implements the Secure Hashing Algorithm 1 as + * defined in FIPS PUB 180-1 published April 17, 1995. + * + * The SHA-1, produces a 160-bit message digest for a given + * data stream. It should take about 2**n steps to find a + * message with the same digest as a given message and + * 2**(n/2) to find any two messages with the same digest, + * when n is the digest size in bits. Therefore, this + * algorithm can serve as a means of providing a + * "fingerprint" for a message. + * + * 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" + +/* Local Function Prototyptes */ +static void _pad_block(struct sha1*); +static void _process_block(struct sha1*); + +/* SHA1 circular left shift */ +static uint32_t _circular_shift(const uint32_t nbits, const uint32_t word) +{ + return ((word << nbits) | (word >> (32 - nbits))); +} + +/* + * sha1_reset + * + * Description: + * This function will initialize the SHA1-context in preparation + * for computing a new SHA1 message digest. + * + * Parameters: + * context: [in/out] + * The context to reset. + * + * Returns: + * sha Error Code. + * + */ +int sha1_reset(struct sha1* context) +{ + if (context == 0) + { + return shaNull; + } + + context->Length_Low = 0; + context->Length_High = 0; + context->Message_Block_Index = 0; + + context->Intermediate_Hash[0] = 0x67452301; + context->Intermediate_Hash[1] = 0xEFCDAB89; + context->Intermediate_Hash[2] = 0x98BADCFE; + context->Intermediate_Hash[3] = 0x10325476; + context->Intermediate_Hash[4] = 0xC3D2E1F0; + + context->flags = 0; + + return shaSuccess; +} + +/* + * sha1_result + * + * Description: + * This function will return the 160-bit message digest into the + * Message_Digest array provided by the caller. + * NOTE: The first octet of hash is stored in the 0th element, + * the last octet of hash in the 19th element. + * + * Parameters: + * context: [in/out] + * The context to use to calculate the SHA-1 hash. + * Message_Digest: [out] + * Where the digest is returned. + * + * Returns: + * sha Error Code. + * + */ +int sha1_result(struct sha1* context, uint8_t Message_Digest[SHA1HashSize]) +{ + int i; + + if ( (context == 0) + || (Message_Digest == 0)) + { + return shaNull; + } + + if ((context->flags & FLAG_CORRUPTED) != 0) + { + return shaStateError; + } + + if ((context->flags & FLAG_COMPUTED) == 0) + { + _pad_block(context); + + for (i = 0; i < 64; ++i) + { + /* message may be sensitive, clear it out */ + context->Message_Block[i] = 0; + } + context->Length_Low = 0; /* and clear length */ + context->Length_High = 0; + context->flags |= FLAG_COMPUTED; + } + + for (i = 0; i < SHA1HashSize; ++i) + { + Message_Digest[i] = (context->Intermediate_Hash[i >> 2] >> (8 * (3 - (i & 0x03)))); + } + + return shaSuccess; +} + +/* + * sha1_input + * + * Description: + * This function accepts an array of octets as the next portion + * of the message. + * + * Parameters: + * context: [in/out] + * The SHA 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: + * sha Error Code. + * + */ +int sha1_input(struct sha1* context, const uint8_t* message_array, unsigned length) +{ + if (length == 0) + { + return shaSuccess; + } + + if ( (context == 0) + || (message_array == 0)) + { + return shaNull; + } + + if ((context->flags & FLAG_COMPUTED) != 0) + { + context->flags |= FLAG_CORRUPTED; + return shaStateError; + } + + if ((context->flags & FLAG_CORRUPTED) != 0) + { + return shaStateError; + } + + while ( (length != 0) + && (context->flags == 0)) + { + context->Message_Block[context->Message_Block_Index] = (*message_array); + + context->Message_Block_Index += 1; + context->Length_Low += 8; + + if (context->Length_Low == 0) + { + context->Length_High += 1; + + if (context->Length_High == 0) + { + /* Message is too long */ + context->flags |= FLAG_CORRUPTED; + } + } + + if (context->Message_Block_Index == 64) + { + _process_block(context); + } + + message_array += 1; + length -= 1; + } + + return shaSuccess; +} + +/* + * _process_block + * + * 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 this code, especially the + * single character names, were used because those were the + * names used in the publication. + * + * + */ +#if 0 // original code +static void _process_block(struct sha1 *context) +{ + const uint32_t K[] = /* Constants defined in SHA-1 */ + { + 0x5A827999, + 0x6ED9EBA1, + 0x8F1BBCDC, + 0xCA62C1D6 + }; + uint32_t t; /* Loop counter */ + uint32_t temp; /* Temporary word value */ + uint32_t W[80]; /* Word sequence */ + uint32_t A, B, C, D, E; /* Word buffers */ + + /* + * Initialize the first 16 words in the array W + */ + for (t = 0; t < 16; ++t) + { + W[t] = context->Message_Block[(t * 4) + 0] << 24; + W[t] |= context->Message_Block[(t * 4) + 1] << 16; + W[t] |= context->Message_Block[(t * 4) + 2] << 8; + W[t] |= context->Message_Block[(t * 4) + 3] << 0; + } + + for (t = 16; t < 80; ++t) + { + W[t] = _circular_shift(1, W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16]); + } + + A = context->Intermediate_Hash[0]; + B = context->Intermediate_Hash[1]; + C = context->Intermediate_Hash[2]; + D = context->Intermediate_Hash[3]; + E = context->Intermediate_Hash[4]; + + for (t = 0; t < 20; ++t) + { + temp = _circular_shift(5, A) + + ((B & C) | ((~B) & D)) + E + W[t] + K[0]; + E = D; + D = C; + C = _circular_shift(30, B); + B = A; + A = temp; + } + + for (; t < 40; ++t) + { + temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[t] + K[1]; + E = D; + D = C; + C = _circular_shift(30, B); + B = A; + A = temp; + } + + for (; t < 60; ++t) + { + temp = _circular_shift(5, A) + + ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2]; + E = D; + D = C; + C = _circular_shift(30, B); + B = A; + A = temp; + } + + for (; t < 80; ++t) + { + temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[t] + K[3]; + E = D; + D = C; + C = _circular_shift(30, B); + B = A; + A = temp; + } + + context->Intermediate_Hash[0] += A; + context->Intermediate_Hash[1] += B; + context->Intermediate_Hash[2] += C; + context->Intermediate_Hash[3] += D; + context->Intermediate_Hash[4] += E; + + context->Message_Block_Index = 0; +} + +#else + +//#define METHOD2 + void _process_block(struct sha1 *context) + { + const uint32_t K[] = /* Constants defined in SHA-1 */ + { + 0x5A827999, + 0x6ED9EBA1, + 0x8F1BBCDC, + 0xCA62C1D6 + }; + uint8_t t; /* Loop counter */ + uint32_t temp; /* Temporary word value */ +#ifdef METHOD2 + uint8_t s; + uint32_t W[16]; +#else + uint32_t W[80]; /* Word sequence */ +#endif + uint32_t A, B, C, D, E; /* Word buffers */ + + /* + * Initialize the first 16 words in the array W + */ + for (t = 0; t < 16; ++t) + { + W[t] = ((uint32_t)context->Message_Block[t * 4 + 0]) << 24; + W[t] |= ((uint32_t)context->Message_Block[t * 4 + 1]) << 16; + W[t] |= ((uint32_t)context->Message_Block[t * 4 + 2]) << 8; + W[t] |= ((uint32_t)context->Message_Block[t * 4 + 3]) << 0; + } + +#ifndef METHOD2 + for (t = 16; t < 80; ++t) + { + W[t] = _circular_shift(1, (W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16])); + } +#endif + + A = context->Intermediate_Hash[0]; + B = context->Intermediate_Hash[1]; + C = context->Intermediate_Hash[2]; + D = context->Intermediate_Hash[3]; + E = context->Intermediate_Hash[4]; + + for (t = 0; t < 20; ++t) + { +#ifdef METHOD2 + s = t & 0x0f; + if (t >= 16) + { + W[s] = _circular_shift(1, (W[(s + 13) & 0x0f] ^ W[(s + 8) & 0x0f] ^ W[(s + 2) & 0x0f] ^ W[s])); + } + temp = _circular_shift(5, A) + ((B & C) | ((~B) & D)) + E + W[s] + K[0]; +#else + temp = _circular_shift(5, A) + ((B & C) | ((~B) & D)) + E + W[t] + K[0]; +#endif + E = D; + D = C; + C = _circular_shift(30, B); + B = A; + A = temp; + } + + for (t = 20; t < 40; ++t) + { +#ifdef METHOD2 + s = (t & 0x0f); + W[s] = _circular_shift(1, (W[(s + 13) & 0x0f] ^ W[(s + 8) & 0x0f] ^ W[(s + 2) & 0x0f] ^ W[s])); + temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[s] + K[1]; +#else + temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[t] + K[1]; +#endif + E = D; + D = C; + C = _circular_shift(30, B); + B = A; + A = temp; + } + + for (t = 40; t < 60; ++t) + { +#ifdef METHOD2 + s = (t & 0x0f); + W[s] = _circular_shift(1, (W[(s + 13) & 0x0f] ^ W[(s + 8) & 0x0f] ^ W[(s + 2) & 0x0f] ^ W[s])); + temp = _circular_shift(5, A) + ((B & C) | (B & D) | (C & D)) + E + W[s] + K[2]; +#else + temp = _circular_shift(5, A) + ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2]; +#endif + E = D; + D = C; + C = _circular_shift(30, B); + B = A; + A = temp; + } + + for (t = 60; t < 80; ++t) + { +#ifdef METHOD2 + s = (t & 0x0f); + W[s] = _circular_shift(1, (W[(s + 13) & 0x0f] ^ W[(s + 8) & 0x0f] ^ W[(s + 2) & 0x0f] ^ W[s])); + temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[s] + K[3]; +#else + temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[t] + K[3]; +#endif + E = D; + D = C; + C = _circular_shift(30, B); + B = A; + A = temp; + } + + context->Intermediate_Hash[0] += A; + context->Intermediate_Hash[1] += B; + context->Intermediate_Hash[2] += C; + context->Intermediate_Hash[3] += D; + context->Intermediate_Hash[4] += E; + + context->Message_Block_Index = 0; + } + +#endif + + +/* + * _pad_block + * + * 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 the ProcessMessageBlock function + * provided appropriately. When it returns, it can be assumed that + * the message digest has been computed. + * + * Parameters: + * context: [in/out] + * The context to pad + * ProcessMessageBlock: [in] + * The appropriate SHA*ProcessMessageBlock function + * Returns: + * Nothing. + * + */ +static void _pad_block(struct sha1* 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; + context->Message_Block_Index += 1; + + while (context->Message_Block_Index < 64) + { + context->Message_Block[context->Message_Block_Index] = 0; + context->Message_Block_Index += 1; + } + + _process_block(context); + + while (context->Message_Block_Index < 56) + { + context->Message_Block[context->Message_Block_Index] = 0; + context->Message_Block_Index += 1; + } + } + else + { + context->Message_Block[context->Message_Block_Index] = 0x80; + context->Message_Block_Index += 1; + + while (context->Message_Block_Index < 56) + { + context->Message_Block[context->Message_Block_Index] = 0; + context->Message_Block_Index += 1; + } + } + + /* + * Store the message length as the last 8 bytes + */ + context->Message_Block[56] = context->Length_High >> 24; + context->Message_Block[57] = context->Length_High >> 16; + context->Message_Block[58] = context->Length_High >> 8; + context->Message_Block[59] = context->Length_High >> 0; + context->Message_Block[60] = context->Length_Low >> 24; + context->Message_Block[61] = context->Length_Low >> 16; + context->Message_Block[62] = context->Length_Low >> 8; + context->Message_Block[63] = context->Length_Low >> 0; + + _process_block(context); +} + + + + + |