加密解密-替换加解密

加密解密-替换加解密

按一定规则重新替换明文的字符生成密文。

可以有多种替换方式。

#include 

void encrypt(char* strData, int nCode)
{
    int i = 0;
    char* p = NULL;
    int nLen = strlen(strData);
    
    if (nLen == 0)
    {
        return;
    }

    printf("original: %s\n", strData);
    p = strData;
    for (i = 0; i < nLen; i++)
    {
        *p = *p + nCode;
        p++;
    }
    printf("encoded: %s\n", strData);
}

void deencrypt(char* strData, int nCode )
{
    int i = 0;
    char* p = NULL;
    int nLen = strlen(strData);

    if (nLen == 0)
    {
        return;
    }

    printf("encode: %s\n", strData);
    p = strData;
    for (i = 0; i < nLen; i++)
    {
        *p = *p - nCode;
        p++;
    }
    printf("original: %s\n", strData);
}


int main()
{
    char testData[16] = "ABCDEFGHIJK";

    printf("=======================\n");
    encrypt(testData, 5);

    printf("=======================\n");
    deencrypt(testData, 5);


    return 0;
}