线性反馈移位寄存器（LFSR）：通常由移位寄存器和异或门逻辑组成

#include <stdio.h> #include <string.h> unsigned char arrayCx[20] = {1,0,0,1,1,0,1,1}; // 二维码1数据 unsigned char arrayGx[20] = {0,1,1,1,0,0,0,1}; // 二维码2数据 unsigned char gLen = 8; // 二维码1数组长度 void lfsrArithmetic(unsigned int cx,unsigned int gx); void arrayPro(unsigned char arrcx[],unsigned char arrgx[],char arrayLen); void main() { //lfsrArithmetic(0XD9,0X8E); // arrayPro(arrayCx,arrayGx,gLen); } /* void lfsrArithmetic(unsigned int cx,unsigned int gx) 输入参数： unsigned char arrcx[] 二维码1数据 unsigned char arrgx[] 二维码2数据 char arrayLen 二维码1数组长度 */ void arrayPro(unsigned char arrcx[],unsigned char arrgx[],char arrayLen) { unsigned int cx = 0; unsigned int gx = 0; unsigned char i = 0; printf("二维码1数据： "); for(i=0;i<arrayLen;i++) { printf("%d ",arrcx[i]); } printf("\n二维码2数据： "); for(i=0;i<arrayLen;i++) { printf("%d ",arrgx[i]); } printf("\n二维码1数组长度： "); printf("%d\n",arrayLen); for(i=0;i<arrayLen;i++) { cx = cx<<1; cx = cx|(unsigned char)arrcx[arrayLen-1-i]; gx = gx<<1; gx = gx|(unsigned char)arrgx[arrayLen-1-i]; } //printf("%X %X \n",cx,gx); lfsrArithmetic(cx,gx); } /* void lfsrArithmetic(unsigned int cx,unsigned int gx) 输入参数： unsigned int cx 表示原始数据 unsigned int gx 表示原多项式，抽头 如： A{1,1,1,1} CX = 0X0F B{1,0,0,1} GX = 0X09 开启码：0xF5、0x91、0xEB、0x23、0xD6、0x47 如： A{1,1,0,1,1,0,1,1} 高位在后 低位在前 CX = 0XDB B{0,1,1,1,0,0,0,1} 高位在后 低位在前 GX = 0X8E 开启码：0xDB、0xFA、0x8D、0x81、0xF2、0xD0 如： A{1,0,0,1,1,0,1,1} 高位在后 低位在前 CX = 0XD9 B{0,1,1,1,0,0,0,1} 高位在后 低位在前 GX = 0X8E 开启码：0x9B、0x03、0xE5、0xA0、0x85、0xDC */ void lfsrArithmetic(unsigned int cx,unsigned int gx) { int lin[20] = {0}; int i = 0,j = 0,k = 0; int orRes = 0; unsigned int dec = 0X00000001; int cnt = 0; unsigned int Cx = 0; // 寄存器的值 unsigned int Qn[10000] = {0}; // 输出结果 unsigned char password[6] = {0}; unsigned char res = 0; int index = 0; unsigned int temp = 0; unsigned int tempCx = 0; Cx = cx; // 寄存器赋初值，寄存器高位为Cx的最低位 tempCx = cx; temp = Cx; // 斐波那契(外部LFSR) (g3, g2, g1, g0) = (1, 0, 0, 1) 表示抽头 //printf("%d%d%d%d\n",(Cx&0X08)>>3,(Cx&0X04)>>2,(Cx&0X02)>1,Cx&0X01); while(1) { Qn[index] = Cx&0X00000001; index++; dec = 0X00000001; tempCx = cx; cnt = 0; memset(lin,0,sizeof(lin)); while(0 != tempCx) { if((gx&dec) == dec) { lin[cnt] = (Cx&dec)>>cnt; } dec = dec<<1; tempCx = tempCx>>1; cnt++; } Cx = Cx>>1; orRes = lin[0]; for(i=1;i<cnt;i++) { orRes = orRes^lin[i]; } Cx = (orRes<<(cnt-1))|Cx; if(temp == Cx) { break; } if(index>255) { break; } } for(i=0;i<20;i++) { for(j = 0;j < index;j++) { Qn[i*(index)+j] = Qn[j]; } } for(i=0;i<6;i++) { for(j=0;j<8;j++) { res = res<<1; res = res|(unsigned char)Qn[j+k]; } k = k+8; password[i] = res; res = 0; } printf("开启码："); for(i = 0;i < 6;i++) { printf("%X ",password[i]); } puts(""); }