加密算法通過對(duì)原文的每個(gè)字符進(jìn)行異或運(yùn)算來進(jìn)行加密；解密時(shí)同樣進(jìn)行異或處理即可恢復(fù)到原文。

代碼實(shí)現(xiàn)如下文章來源地址http://www.zghlxwxcb.cn/news/detail-555133.html

#include<stdlib.h>
#include <stdio.h>

int getfilesize(char *path)
{ 
    FILE *pf = fopen(path, "r");
    if (pf == NULL)
    { 
        return -1;
    }
    else
    { 
        fseek(pf, 0, SEEK_END);
        int length = ftell(pf);
        return length;
    }
}

void EncryptFile(char *oldpath, char *newpath)
{ 
    int i = 0;
    FILE *pfr, *pfw;
    pfr = fopen(oldpath, "rb");
    pfw = fopen(newpath, "wb");
    if (pfr == NULL || pfw == NULL)
    { 
        fclose(pfr);
        fclose(pfw);
        return;
    }
    else
    { 
        int length = getfilesize(oldpath);
        char *p = (char *)malloc(length*sizeof(char));
        fread(p, sizeof(char), length, pfr);
        for (i = 0; i < length; i++)
        { 
            p[i] ^= 'A';
        }
        fwrite(p, sizeof(char), length, pfw);
        fclose(pfr);
        fclose(pfw);
    }
}
void DecryptFile(char *oldpath, char *newpath)
{ 
    int i = 0;
    FILE *pfr, *pfw;
    pfr = fopen(oldpath, "rb");
    pfw = fopen(newpath, "wb");
    if (pfr == NULL || pfw == NULL)
    { 
        fclose(pfr);
        fclose(pfw);
        return;
    }
    else
    { 
        int length = getfilesize(oldpath);
        char *p = (char *)malloc(length*sizeof(char));
        fread(p, sizeof(char), length, pfr);
        for (i = 0; i < length; i++)
        { 
            p[i] ^= 'A';
        }
        fwrite(p, sizeof(char), length, pfw);
        fclose(pfr);
        fclose(pfw);
    }
}
#if 0
void main()
{           
    // 原始文件的路徑
    char *oldpath = "log.txt";
    // 加密后的路徑
    char *newpath = "log-EecryptFile.dat";
    // 解密后的路徑
    char *newDecryptFilepath = "log-DecryptFile.txt";
    EncryptFile(oldpath, newpath);
    DecryptFile(newpath, newDecryptFilepath);
}
#endif