加密与解密的简单实现

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简单字符加密

#include<stdio.h>#include<stdlib.h>void main(){char strsrc[20] = "i love you";printf("\n加密前:%s",strsrc);int i;for (i = 0; i < 20; i++){strsrc[i] += i;}printf("\n加密后:%s", strsrc);for (i = 0; i < 20; i++){strsrc[i] -= i;}printf("\n解密后:%s", strsrc);system("pause");}

2.按照密码加密

#include<stdio.h>#include<stdlib.h>#include<string.h>void encryption(char *src, char *code){int len1 = strlen(src);int len2 = strlen(code);int i, j;for (i = 0; i < len1 / len2; i++){for (j = 0; j < len2; j++){src[i*len2 + j] += code[j];}}for (i = 0; i < len1%len2; i++){src[len1/len2*len2+1] += code[i];}printf("\n%s", src);}void decryption(char *src, char *code){int len1 = strlen(src);int len2 = strlen(code);int i, j;for (i = 0; i < len1 / len2; i++){for (j = 0; j < len2; j++){src[i*len2 + j] -= code[j];}}for (i = 0; i < len1%len2; i++){src[i] -= code[i];}printf("\n%s", src);}void main(){char strsrc[30] = "please encrypt this sentence";char password[8] = { 0 };printf("\n加密前:%s",strsrc);printf("\n加密后:");encryption(strsrc, "1314521");printf("\n解密后:");decryption(strsrc, "1314521");system("pause");}

3.加密文本文件

#define _CRT_SECURE_NO_WARNINGS#include<stdio.h>#include<stdlib.h>#include<string.h>char *srcpath = "C:\\Users\\lucifer\\Desktop\\src.txt";char *encryptedpath = "C:\\Users\\lucifer\\Desktop\\encrypted.txt";char *decryptedpath = "C:\\Users\\lucifer\\Desktop\\decrypted.txt";int  GetFileSize(char *path){FILE *fp = fopen(path, "r");if(fp){fseek(fp, 0, SEEK_END);int size = ftell(fp);return size;}return -1;}void encryption(char *srcpath, char *codepath){FILE *pSrc = fopen(srcpath, "r");FILE *pCode = fopen(codepath, "w");int i;if (!pSrc || !pCode){printf("\n文件打开失败");return;}int len1 = GetFileSize(srcpath);for (i = 0; i < len1; i++){char ch = fgetc(pSrc);fputc(ch+4, pCode);}fclose(pCode);fclose(pSrc);system(codepath);}void decryption(char *srcpath, char *codepath){FILE *pSrc = fopen(srcpath, "r");FILE *pCode = fopen(codepath, "w");int i;if (!pSrc || !pCode){printf("\n文件打开失败");return;}int len1 = GetFileSize(srcpath);//int len2 = GetFileSize(codepath);for (i = 0; i < len1; i++){char ch = fgetc(pSrc);fputc(ch-4 , pCode);}fclose(pCode);fclose(pSrc);system(codepath);}void main(){encryption(srcpath, encryptedpath);decryption(encryptedpath, decryptedpath);system("pause");}

4.加密二进制文件

#define _CRT_SECURE_NO_WARNINGS#include<stdio.h>#include<stdlib.h>#include<string.h>char *srcpath = "C:\\Users\\lucifer\\Desktop\\电脑管家.lnk";char *encryptedpath = "C:\\Users\\lucifer\\Desktop\\1.txt";char *decryptedpath = "C:\\Users\\lucifer\\Desktop\\2.lnk";int GetFileSize(char *path){FILE *fp = fopen(path, "rb");if (fp){fseek(fp, 0, SEEK_END);int len = ftell(fp);return len;}return -1;}void encryption(char *srcpath, char *codepath){FILE *pSrc = fopen(srcpath, "rb");FILE *pCode = fopen(codepath, "wb");int i;if (!pSrc || !pCode){printf("文件打开失败");return;}int size = GetFileSize(srcpath);char *p = (char *)malloc(sizeof(char)*size);fread(p, 1, size, pSrc);for (i = 0; i < size; i++){p[i] += 1;}fwrite(p, 1, size, pCode);fclose(pCode);fclose(pSrc);system(codepath);}void decryption(char *srcpath, char *codepath){FILE *pSrc = fopen(srcpath, "rb");FILE *pCode = fopen(codepath, "wb");int i;if (!pSrc || !pCode){printf("文件打开失败");return;}int size = GetFileSize(srcpath);char *p = (char *)malloc(sizeof(char)*size);fread(p, 1, size, pSrc);for (i = 0; i < size; i++){p[i] -= 1;}fwrite(p, 1, size, pCode);fclose(pCode);fclose(pSrc);}void main(){encryption(srcpath, encryptedpath);decryption(encryptedpath,decryptedpath);system(decryptedpath);system("pause");}

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