NSWFL_SHA1.cpp

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//  Copyright © NetworkDLS 2023, All rights reserved
//
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF 
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO 
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A 
// PARTICULAR PURPOSE.
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#ifndef _NSWFL_SHA1_CPP_
#define _NSWFL_SHA1_CPP_
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#include "NSWFL.H"

#ifdef _USE_GLOBAL_MEMPOOL
extern NSWFL::Memory::MemoryPool *pMem; //pMem must be defined and initalized elsewhere.
#endif

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

namespace NSWFL {
	namespace Hashing {
		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

/*
 *	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.
 *
 */

 ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

 //Return 40+1 (hash+null) characters through sOut.
		bool SimpleSHA1(const char *sStr, int iStrSz, char *sOut, int iMaxSz)
		{
			bool bResult = false;
			SHA1 SHA;
			SHA.Input(sStr, iStrSz);

			bResult = SHA.ToString(sOut, iMaxSz);

			SHA.Reset();
			memset(&SHA, 0, sizeof(SHA1));

			return bResult;
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

		//Return 40+1 (hash+null) characters through sOut.
		bool SimpleSHA1(const char *sStr, char *sOut, int iMaxSz)
		{
			return SimpleSHA1(sStr, (int)strlen(sStr), sOut, iMaxSz);
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		//This is the constructor for the sha1 class.

		SHA1::SHA1()
		{
			Reset();
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		//This is the destructor for the sha1 class

		SHA1::~SHA1()
		{
			// The destructor does nothing
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		//This function will initialize the sha1 class member variables
		//	in preparation for computing a new message digest.

		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;
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		/*
		 *	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.
		*/

		bool SHA1::Result(unsigned long *message_digest_array)
		{
			int i = 0; // Counter

			if (Corrupted)
			{
				return false;
			}

			if (!Computed)
			{
				PadMessage();
				Computed = true;
			}

			for (i = 0; i < 5; i++)
			{
				message_digest_array[i] = H[i];
			}

			return true;
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		//Returns 41 bytes: 40 for the hash 1 for the terminating null.

		bool SHA1::ToString(char *sOut, int iMaxSz)
		{
			unsigned long ulDigest[5];
			if (this->Result(ulDigest))
			{
				return this->ToString(ulDigest, sOut, iMaxSz);
			}
			else return false;
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		//Returns 41 bytes: 40 for the hash 1 for the terminating null.

		bool SHA1::ToString(unsigned long *MessageDigest, char *sOut, int iMaxSz)
		{
			if (iMaxSz >= 41)
			{
				char sSegment[8 + 1];

				sOut[0] = 0;

				int iPadding = 0;
				int iSegmentSz = 0;
				int iWPos = 0;
				int iRPos = 0;

				for (int i = 0; i < 5; i++)
				{
					iSegmentSz = sprintf_s(sSegment, sizeof(sSegment), "%X", MessageDigest[i]);

					iPadding = (8 - iSegmentSz);

					for (iRPos = 0; iRPos < iPadding; iRPos++)
					{
						sOut[iWPos++] = '0';
					}

					for (iRPos = 0; iRPos < iSegmentSz; iRPos++)
					{
						sOut[iWPos++] = sSegment[iRPos];
					}
				}
				sOut[iWPos] = '\0';
				return true;
			}

			return false;
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		/*
		 *	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.
		 *
		*/
		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++;
			}
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		/*
		 *	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
		*/
		void SHA1::Input(const char *message_array, unsigned length)
		{
			Input((unsigned char *)message_array, length);
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		/*
		 *	Description:
		 *		This function accepts a single octets as the next message element.
		 *
		 *	Parameters:
		 *		message_element: [in]
		 *			The next octet in the message.
		*/

		void SHA1::Input(unsigned char message_element)
		{
			Input(&message_element, 1);
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		/*
		 *	Description:
		 *		This function accepts a single octet as the next message element.
		 *
		 *	Parameters:
		 *		message_element: [in]
		 *			The next octet in the message.
		 */
		void SHA1::Input(char message_element)
		{
			Input((unsigned char *)&message_element, 1);
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		/*
		 *	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;
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		/*
		 *	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.
		 */
		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();
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		/*
		 *	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.
		 */
		unsigned SHA1::CircularShift(int bits, unsigned word)
		{
			return ((word << bits) & 0xFFFFFFFF) | ((word & 0xFFFFFFFF) >> (32 - bits));
		}

		///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
	} //namespace::Hashing
} //namespace::NSWFL
#endif