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Diffstat (limited to 'src/sha1.cpp')
| -rw-r--r-- | src/sha1.cpp | 593 |
1 files changed, 593 insertions, 0 deletions
diff --git a/src/sha1.cpp b/src/sha1.cpp new file mode 100644 index 0000000..7fe99e0 --- /dev/null +++ b/src/sha1.cpp @@ -0,0 +1,593 @@ +/* + * sha1.cpp + * + * Copyright (C) 1998, 2009 + * Paul E. Jones <paulej@packetizer.com> + * All Rights Reserved. + * + ***************************************************************************** + * $Id: sha1.cpp 12 2009-06-22 19:34:25Z paulej $ + ***************************************************************************** + * + * Description: + * This class 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 8 + * bits. + * + */ + + +#include "sha1.hpp" + +namespace sha { + +/* + * SHA1 + * + * Description: + * This is the constructor for the sha1 class. + * + * Parameters: + * None. + * + * Returns: + * Nothing. + * + * Comments: + * + */ +SHA1::SHA1() +{ + Reset(); +} + +/* + * ~SHA1 + * + * Description: + * This is the destructor for the sha1 class + * + * Parameters: + * None. + * + * Returns: + * Nothing. + * + * Comments: + * + */ +SHA1::~SHA1() +{ + // The destructor does nothing +} + +/* + * Reset + * + * Description: + * This function will initialize the sha1 class member variables + * in preparation for computing a new message digest. + * + * Parameters: + * None. + * + * Returns: + * Nothing. + * + * Comments: + * + */ +void SHA1::Reset() +{ + Length_Low = 0; + Length_High = 0; + Message_Block_Index = 0; + + H[0] = 0x67452301; + H[1] = 0xEFCDAB89; + H[2] = 0x98BADCFE; + H[3] = 0x10325476; + H[4] = 0xC3D2E1F0; + + Computed = false; + Corrupted = false; +} + +/* + * Result + * + * Description: + * This function will return the 160-bit message digest into the + * array provided. + * + * Parameters: + * message_digest_array: [out] + * This is an array of five unsigned integers which will be filled + * with the message digest that has been computed. + * + * Returns: + * True if successful, false if it failed. + * + * Comments: + * + */ +bool SHA1::Result(unsigned *message_digest_array) +{ + int i; // Counter + + if (Corrupted) + { + return false; + } + + if (!Computed) + { + PadMessage(); + Computed = true; + } + + for(i = 0; i < 5; i++) + { + message_digest_array[i] = H[i]; + } + + return true; +} + +/* + * Input + * + * Description: + * This function accepts an array of octets as the next portion of + * the message. + * + * Parameters: + * message_array: [in] + * An array of characters representing the next portion of the + * message. + * + * Returns: + * Nothing. + * + * Comments: + * + */ +void SHA1::Input( const unsigned char *message_array, + unsigned length) +{ + if (!length) + { + return; + } + + if (Computed || Corrupted) + { + Corrupted = true; + return; + } + + while(length-- && !Corrupted) + { + Message_Block[Message_Block_Index++] = (*message_array & 0xFF); + + Length_Low += 8; + Length_Low &= 0xFFFFFFFF; // Force it to 32 bits + if (Length_Low == 0) + { + Length_High++; + Length_High &= 0xFFFFFFFF; // Force it to 32 bits + if (Length_High == 0) + { + Corrupted = true; // Message is too long + } + } + + if (Message_Block_Index == 64) + { + ProcessMessageBlock(); + } + + message_array++; + } +} + +/* + * Input + * + * Description: + * This function accepts an array of octets as the next portion of + * the message. + * + * Parameters: + * message_array: [in] + * An array of characters representing the next portion of the + * message. + * length: [in] + * The length of the message_array + * + * Returns: + * Nothing. + * + * Comments: + * + */ +void SHA1::Input( const char *message_array, + unsigned length) +{ + Input((unsigned char *) message_array, length); +} + +/* + * Input + * + * Description: + * This function accepts a single octets as the next message element. + * + * Parameters: + * message_element: [in] + * The next octet in the message. + * + * Returns: + * Nothing. + * + * Comments: + * + */ +void SHA1::Input(unsigned char message_element) +{ + Input(&message_element, 1); +} + +/* + * Input + * + * Description: + * This function accepts a single octet as the next message element. + * + * Parameters: + * message_element: [in] + * The next octet in the message. + * + * Returns: + * Nothing. + * + * Comments: + * + */ +void SHA1::Input(char message_element) +{ + Input((unsigned char *) &message_element, 1); +} + +/* + * operator<< + * + * Description: + * This operator makes it convenient to provide character strings to + * the SHA1 object for processing. + * + * Parameters: + * message_array: [in] + * The character array to take as input. + * + * Returns: + * A reference to the SHA1 object. + * + * Comments: + * Each character is assumed to hold 8 bits of information. + * + */ +SHA1& SHA1::operator<<(const char *message_array) +{ + const char *p = message_array; + + while(*p) + { + Input(*p); + p++; + } + + return *this; +} + +/* + * operator<< + * + * Description: + * This operator makes it convenient to provide character strings to + * the SHA1 object for processing. + * + * Parameters: + * message_array: [in] + * The character array to take as input. + * + * Returns: + * A reference to the SHA1 object. + * + * Comments: + * Each character is assumed to hold 8 bits of information. + * + */ +SHA1& SHA1::operator<<(const unsigned char *message_array) +{ + const unsigned char *p = message_array; + + while(*p) + { + Input(*p); + p++; + } + + return *this; +} + +/* + * operator<< + * + * Description: + * This function provides the next octet in the message. + * + * Parameters: + * message_element: [in] + * The next octet in the message + * + * Returns: + * A reference to the SHA1 object. + * + * Comments: + * The character is assumed to hold 8 bits of information. + * + */ +SHA1& SHA1::operator<<(const char message_element) +{ + Input((unsigned char *) &message_element, 1); + + return *this; +} + +/* + * operator<< + * + * Description: + * This function provides the next octet in the message. + * + * Parameters: + * message_element: [in] + * The next octet in the message + * + * Returns: + * A reference to the SHA1 object. + * + * Comments: + * The character is assumed to hold 8 bits of information. + * + */ +SHA1& SHA1::operator<<(const unsigned char message_element) +{ + Input(&message_element, 1); + + return *this; +} + +/* + * ProcessMessageBlock + * + * 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 function, especially the single + * character names, were used because those were the names used + * in the publication. + * + */ +void SHA1::ProcessMessageBlock() +{ + const unsigned K[] = { // Constants defined for 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) Message_Block[t * 4]) << 24; + W[t] |= ((unsigned) Message_Block[t * 4 + 1]) << 16; + W[t] |= ((unsigned) Message_Block[t * 4 + 2]) << 8; + W[t] |= ((unsigned) Message_Block[t * 4 + 3]); + } + + for(t = 16; t < 80; t++) + { + W[t] = CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]); + } + + A = H[0]; + B = H[1]; + C = H[2]; + D = H[3]; + E = H[4]; + + for(t = 0; t < 20; t++) + { + temp = CircularShift(5,A) + ((B & C) | ((~B) & D)) + E + W[t] + K[0]; + temp &= 0xFFFFFFFF; + E = D; + D = C; + C = CircularShift(30,B); + B = A; + A = temp; + } + + for(t = 20; t < 40; t++) + { + temp = CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1]; + temp &= 0xFFFFFFFF; + E = D; + D = C; + C = CircularShift(30,B); + B = A; + A = temp; + } + + for(t = 40; t < 60; t++) + { + temp = CircularShift(5,A) + + ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2]; + temp &= 0xFFFFFFFF; + E = D; + D = C; + C = CircularShift(30,B); + B = A; + A = temp; + } + + for(t = 60; t < 80; t++) + { + temp = CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3]; + temp &= 0xFFFFFFFF; + E = D; + D = C; + C = CircularShift(30,B); + B = A; + A = temp; + } + + H[0] = (H[0] + A) & 0xFFFFFFFF; + H[1] = (H[1] + B) & 0xFFFFFFFF; + H[2] = (H[2] + C) & 0xFFFFFFFF; + H[3] = (H[3] + D) & 0xFFFFFFFF; + H[4] = (H[4] + E) & 0xFFFFFFFF; + + Message_Block_Index = 0; +} + +/* + * PadMessage + * + * 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 ProcessMessageBlock() appropriately. When it returns, it + * can be assumed that the message digest has been computed. + * + * Parameters: + * None. + * + * Returns: + * Nothing. + * + * Comments: + * + */ +void SHA1::PadMessage() +{ + /* + * 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 (Message_Block_Index > 55) + { + Message_Block[Message_Block_Index++] = 0x80; + while(Message_Block_Index < 64) + { + Message_Block[Message_Block_Index++] = 0; + } + + ProcessMessageBlock(); + + while(Message_Block_Index < 56) + { + Message_Block[Message_Block_Index++] = 0; + } + } + else + { + Message_Block[Message_Block_Index++] = 0x80; + while(Message_Block_Index < 56) + { + Message_Block[Message_Block_Index++] = 0; + } + + } + + /* + * Store the message length as the last 8 octets + */ + Message_Block[56] = (Length_High >> 24) & 0xFF; + Message_Block[57] = (Length_High >> 16) & 0xFF; + Message_Block[58] = (Length_High >> 8) & 0xFF; + Message_Block[59] = (Length_High) & 0xFF; + Message_Block[60] = (Length_Low >> 24) & 0xFF; + Message_Block[61] = (Length_Low >> 16) & 0xFF; + Message_Block[62] = (Length_Low >> 8) & 0xFF; + Message_Block[63] = (Length_Low) & 0xFF; + + ProcessMessageBlock(); +} + + +/* + * CircularShift + * + * Description: + * This member function will perform a circular shifting operation. + * + * Parameters: + * bits: [in] + * The number of bits to shift (1-31) + * word: [in] + * The value to shift (assumes a 32-bit integer) + * + * Returns: + * The shifted value. + * + * Comments: + * + */ +unsigned SHA1::CircularShift(int bits, unsigned word) +{ + return ((word << bits) & 0xFFFFFFFF) | ((word & 0xFFFFFFFF) >> (32-bits)); +} + +}
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