SHA1 加密算法

最新推荐文章于 2020-08-06 22:04:42 发布

转载最新推荐文章于 2020-08-06 22:04:42 发布 · 4.8k 阅读

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#加密 #算法 #null #function #string #input

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本文介绍了一个SHA1哈希算法的具体实现过程，包括输入字符串的预处理、哈希运算的主要步骤和最终结果的输出。通过详细解释SHA1算法的每个部分，帮助读者理解其工作原理。

#include "stdafx.h" #include <string.h> #include <stdlib.h> #include <stdio.h> typedef unsigned __int64 UINT64; #define NULL 0 // The standard SHA1 needs the input string to fit into a block // This function align the input string to meet the requirement void AlignSHA1(const char *pIn,UINT64 *pBlks, UINT64 &nBlksLen) { if (pIn == NULL) { return; } UINT64 nInLen = strlen(pIn); UINT64 nBlk = ((nInLen+8)>>6)+1; if (pBlks == NULL) { nBlksLen = nBlk*16; return; } for (int j=0; j<nBlksLen; j++) { pBlks[j] = 0; } for(UINT64 i=0; i<nInLen; i++) { pBlks[i>>2] |= pIn[i]<<(24-(i&3)*8); } pBlks[i>>2] |= 0x80<<(24-(i&3)*8); pBlks[nBlksLen-1]=(int)(nInLen*8); return ; } // The int32 add function which doesn't generate overflow // exception. This is required by the algorithm UINT64 add(UINT64 x, UINT64 y) { UINT64 lsw = (x&0xffff)+(y&0xffff); UINT64 msw = (x>>16) + (y>>16) +(lsw>>16); return (msw<<16) | (lsw&0xffff); } UINT64 UnsigedRightMove(UINT64 num, UINT64 bit) { num &=0xffffffff; num >>= bit ; return num; } // The int32 _asm rol :) UINT64 rol(UINT64 num,UINT64 cnt) { return(num<<cnt)|UnsigedRightMove(num, (32-cnt)); } // Perform the appropriate triplet combination function for the current round UINT64 ft(UINT64 t, UINT64 b, UINT64 c, UINT64 d) { if(t<20)return(b&c)|((~b)&d); if(t<40)return b^c^d; if(t<60)return(b&c)|(b&d)|(c&d); return b^c^d; } // Determine the appropriate additive constant for the current iteration UINT64 kt(UINT64 t) { return(t<20)?1518500249:(t<40)?1859775393: (t<60)?-1894007588:-899497514; } char* Uint64ToHexStr(UINT64 num, char *buf, int nLen) { if (buf == NULL || nLen<8) { return buf; } char szTemp[9]={0}; ultoa((unsigned long)num, szTemp, 16); static char *s_pZero[]= { "0", "00", "000" "0000", "00000", "000000", "0000000", "00000000", "000000000", }; int nRealLen = strlen(szTemp); int nSpareBit = 7-nRealLen; if (nSpareBit >=0 && nSpareBit <=7) { memcpy(buf, s_pZero[nSpareBit], nSpareBit+1); memcpy(buf+ nSpareBit+1, szTemp, nRealLen); } else { memcpy(buf, szTemp, 8); } return buf; } //#define BAT char* SHA1(unsigned char *pIn, char *pOut, int nOutLen) { if (pIn == NULL) { return pOut; } UINT64 nBlksLen = 0; AlignSHA1((const char*)pIn, NULL, nBlksLen); UINT64 *pBlks = new UINT64[(int)nBlksLen]; if (pBlks == NULL) { return pOut; } AlignSHA1((const char*)pIn, pBlks, nBlksLen); UINT64 w[80] ={0}; UINT64 a = 1732584193; UINT64 b = -271733879; UINT64 c = -1732584194; UINT64 d = 271733878; UINT64 e = -1009589776; for (UINT64 i=0; i<nBlksLen; i+=16) { UINT64 olda=a; UINT64 oldb=b; UINT64 oldc=c; UINT64 oldd=d; UINT64 olde=e; for (UINT64 j=0; j<80; j++) { if (j<16) { w[j]=pBlks[i+j]; } else { w[j]=rol(w[j-3]^w[j-8]^w[j-14]^w[j-16],1); } UINT64 t=add(add(rol(a,5),ft(j,b,c,d)),add(add(e,w[j]),kt(j))); e=d; d=c; c=rol(b,30); b=a; a=t; } a=add(a,olda); b=add(b,oldb); c=add(c,oldc); d=add(d,oldd); e=add(e,olde); } Uint64ToHexStr(a, pOut, nOutLen); Uint64ToHexStr(b, pOut+8, nOutLen-8); Uint64ToHexStr(c, pOut+16, nOutLen-16); Uint64ToHexStr(d, pOut+24, nOutLen-24); Uint64ToHexStr(e, pOut+32, nOutLen-32); if (pBlks != NULL) { delete[] pBlks; pBlks = NULL; } return pOut; } void main() { //定义要sha1的字符串 char pTemp[400]={0}; //定义返回的sha1值 char szHash[41] ={0}; pTemp[0]=0; strcpy(pTemp,"abc"); SHA1((unsigned char*)pTemp, szHash, 41); printf("%s/n",szHash); strcpy(pTemp,szHash); SHA1((unsigned char*)pTemp, szHash, 41); printf("%s/n",szHash); strcpy(pTemp,szHash); SHA1((unsigned char*)pTemp, szHash, 41); printf("%s/n",szHash); }