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athena/src/sha1.cpp

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/*
* sha1.c
*
* Copyright (C) 1998, 2009
* Paul E. Jones <paulej@packetizer.com>
* All Rights Reserved
*
*****************************************************************************
* $Id: sha1.c 12 2009-06-22 19:34:25Z paulej $
*****************************************************************************
*
* 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 u8acters and u8acter
* arrays assume that only 8 bits of information are stored in each
* u8acter.
*
* 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 u8acter.
*
*/
#include "sha1.h"
#include <cstring>
#include "athena/Utility.hpp"
/*
* 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
* Message_Digest array within the SHA1Context provided
*
* Parameters:
* context: [in/out]
* The context to use to calculate the SHA-1 hash.
*
* Returns:
* 1 if successful, 0 if it failed.
*
* Comments:
*
*/
int SHA1Result(SHA1Context* context) {
if (context->Corrupted) {
return 0;
}
if (!context->Computed) {
SHA1PadMessage(context);
context->Computed = 1;
}
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 u8acters 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 u8acter 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);
}
atUint8* getSha1(atUint8* stuff, atUint32 stuff_size) {
SHA1Context sha;
SHA1Reset(&sha);
SHA1Input(&sha, (const atUint8*)stuff, stuff_size);
if (!SHA1Result(&sha))
return 0;
atUint8* ret = new atUint8[20];
memset(ret, 0, 20);
for (int i = 0; i < 5; i++) {
int val = sha.Message_Digest[i];
if (!athena::utility::isSystemBigEndian())
val = athena::utility::swap32(val);
memmove((char*)ret + (i * 4), &val, 4);
}
return ret;
}
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