sha1.h

SHA1算法软件程序实现

/*
 *	sha1.h
 *
 *	Copyright (C) 1998
 *	Paul E. Jones <[e-mail]>
 *	All Rights Reserved.
 *
 *****************************************************************************
 *	$Id: sha1.h,v 1.6 2004/03/27 18:02:26 paulej Exp $
 *****************************************************************************
 *
 *	Description:
 * 		This class implements the Secure Hashing Standard as defined
 * 		in FIPS PUB 180-1 published April 17, 1995.
 *
 *		Many of the variable names in this class, especially the single
 *		character names, were used because those were the names used
 *		in the publication.
 *
 * 		Please read the file sha1.cpp for more information.
 *
 * 		This is the same as MD5.
 * /*
 *  Created on: 2009-3-26
 *      Author: root
 *      usage	:	char SHABuffer[41];
 *					SHA1 SHA;
 *					SHA.SHA_GO("gfc",SHABuffer);
 *					执行完成之后SHABuffer中即存储了由"a string"计算得到的SHA值
 		算法描述：
					1.填充形成整512 bits(64字节), (N+1)*512;
								N*512 + 448位                         64位
						真实数据 + 填充(一个1和无数个0)		 		保存真实数据的长度
						—————————————————————— ----------------------
					2.四个32位被称为连接变量的整数参数：
						A=，B=，C=，D=,E=
					3.开始算法的四轮循环运算。
						循环的次数(N+1)是信息中512位信息分组的数目。
						for(N+1, 每次取512 bits(64字节)来进行处理：)
						{
							512bits 分成16个分组(每个分组4字节。int data[16])
							用16个分组中的每一个分组和A，B，C，D,E通过4个函数进行运算，
							得到新的A，B，C，D,E
						}
					4.最后，将A，B，C，D,E拼接起来就是SHA值
						将拼接后的值用字符串的方式表示出来，就是最终的结果。
						(比如 0x234233F, 用串 “234233F”表示出来，生成的串的空间将是值的空间的2倍。)
 *		调试情况: 该代码已经调试通过。
 */

#ifndef _SHA1_H_
#define _SHA1_H_

#include<string.h>
#include<stdio.h>

class SHA1
{
	public:
		SHA1();
		virtual ~SHA1();
		bool SHA_GO( const char *lpData_Input, char *lpSHACode_Output );
	private:
		unsigned int H[5];					// Message digest buffers
		unsigned int Length_Low;				// Message length in bits
		unsigned int Length_High;			// Message length in bits
		unsigned char Message_Block[64];	// 512-bit message blocks
		int Message_Block_Index;				// Index into message block array
	private:
		void SHAInit();
		void AddDataLen(int nDealDataLen);

		// Process the next 512 bits of the message
		void ProcessMessageBlock();

		// Pads the current message block to 512 bits
		void PadMessage();

		// Performs a circular left shift operation
		inline unsigned CircularShift(int bits, unsigned word);
};

#endif