【综合】简单加解密——寻找序列号

下面文字对你可能有用(复制+粘贴):

#include <stdlib.h>

#include <string.h>
#include “malloc.h”
#define MaxPass 66 // 最多66段密文
#define NumbPwdTable 5 // 密码表的份数
#define SizePwdTable 0x210 // 每份密码表占用字节数

struct PassStru // 密码表结构: 编移(4字节),密文长度(2字节),钥匙(1字节)。结构体长度此处须为 4的倍数
{unsigned int Offset; unsigned short int Size; unsigned char Key; char cJiangYou;} // cJiangYou打酱油

char MsgErr[]=“Wrong Key!”,MsgSn[]="Serial No.: ",MsgMD9[]="MD9: ";

文件下载

话说这些文件被我放在我的“图床”里了哈哈哈，有人能get到我的笑点吗
VxCrp2018A1.VDF
VxCrp2018A2.VDF
VxCrp2018A3.VDF
VxCrp2018A4.VDF
VxCrp2018A5.VDF
VxCrp2018A6.VDF
VxCrp2018A7.VDF

思路

真的很简单就是按照题目模拟就行了，没有特别的，这道题的文件结构很简单也用不到KMP，所以就不多解释了

代码

#include <stdio.h>
#include <string.h>
struct key{unsigned int offset;unsigned short size;unsigned char K;
}table;
int main(){char pos[20],ciph[10000];int N,i,j = 1,s,m;scanf("%s\n%d",pos,&N);FILE *fp = fopen(pos,"rb");for(i = 0;i < 5;i++){fseek(fp,(N-1)*8+i*0x210,0);fread(&(table.offset),7,1,fp);fseek(fp,table.offset,0);fread(ciph,table.size,1,fp);ciph[0] += table.K;if(ciph[0] == 'W') continue;else{while(j < table.size){ciph[j] += table.K;if(ciph[j] == 'e' && ciph[j - 1] == 'S') s = j - 1;if(ciph[j] == 'D' && ciph[j - 1] == 'M') m = j - 1;j ++;}break;}}printf("XH: %02d\n",N);printf("SN: %.19s\n",ciph + s + 12);printf("M9: %.32s\n",ciph + m + 5);
}

或者

#include <stdio.h>
#include <string.h>
struct key{unsigned int offset;unsigned short size;unsigned char K;
}table;
int main(){char pos[20],ciph[10000];int N,i;scanf("%s\n%d",pos,&N);FILE *fp = fopen(pos,"rb");for(int i = 0;i < 5;i++){fseek(fp,(N-1)*8+i*0x210,0);fread(&(table.offset),7,1,fp);fseek(fp,table.offset,0);fread(ciph,table.size,1,fp);for(int j = 0;j < table.size;j++) ciph[j] += table.K;if(!strncmp(ciph,"Wrong Key!",9)) continue;else break;}printf("XH: %02d\n",N);for(i = 0;;i++){if(strncmp(ciph+i,"Serial No.: ",11)==0){printf("SN: %.19s\n",ciph + i + 12);break;}}for(;;i++){if(strncmp(ciph+i,"MD9: ",4)==0){printf("M9: %.32s\n",ciph + i + 5);break;}}
}

java版

鉴于有个小朋友一直想要JAVA版，所以写了一下（java对二进制的读取是真滴难受，有大佬有好的方法请教给我）

import java.io.*;public class Main {public static void main(String[] args) throws IOException {BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));String pos = reader.readLine();int N = Integer.parseInt(reader.readLine());FileInputStream fp = new FileInputStream(pos);byte[] ciph = null;int s = 0;int m = 0;for (int i = 0; i < 5; i++) {fp.getChannel().position((N - 1) * 8 + i * 0x210);DataInputStream dis = new DataInputStream(fp);//下面这三行就是我吐槽的地方了int offset = Integer.reverseBytes(dis.readInt());int size = dis.readUnsignedShort();int K = dis.readUnsignedByte();Key table = new Key(offset, size, K);fp.getChannel().position(table.offset);ciph = new byte[table.size];fp.read(ciph);ciph[0] += table.K;if (ciph[0] == 'W') continue;else {int j = 0;for(int t = 0; t < table.size; t ++) ciph[t] += table.K;while (++j < table.size){if (ciph[j] == 'e' && ciph[j - 1] == 'S') s = j - 1;if (ciph[j] == 'D' && ciph[j - 1] == 'M') m = j - 1;if(s != 0 && m != 0) break;//都找到就可以走了}break;}}fp.close();System.out.printf("XH: %02d\n", N);System.out.printf("SN: %.19s\n", new String(ciph, s + 12, 19));System.out.printf("M9: %.32s\n", new String(ciph, m + 5, 32));}
}class Key {int offset;int size;int K;public Key(int offset, int size, int K) {this.offset = offset;this.size = size;this.K = K;}
}