XOR加密适用于不在Visual Studio 2017上的代码块

Question

所以我想在写入.txt文件时加密我的数据,所以我从这段代码中选择XOR-Encryption: Github 所以当我在代码块中运行它运行并显示这个结果:

Encrypted: :=.43*-:8m2$.a
Decrypted:kylewbanks.com0

Process returned 0 (0x0)   execution time : 0.025 s
Press any key to continue.

但是,当我开始使用Visual Studio 2017时,它显示以下错误:

Error (active)  E0059   function call is not allowed in a constant expression   

这意味着在声明数组时我无法放置变量,所以我的加密方法是否适用于VS2017.我认为问题是当使用常量声明变量时,无论如何强制它或其他易于使用的加密方法,我不需要是安全的只是为了防止文件中的纯文本.无论如何这是唯一的代码:

#include <stdio.h>
#include <string.h>

void encryptDecrypt(char *input, char *output) {
    char key[] = {'K', 'C', 'Q'}; //Can be any chars, and any size array

    int i;
    for(i = 0; i < strlen(input); i++) {
        output[i] = input[i] ^ key[i % (sizeof(key)/sizeof(char))];
    }
}

int main () {
    char baseStr[] = "kylewbanks.com";

    char encrypted[strlen(baseStr)];
    encryptDecrypt(baseStr, encrypted);
    printf("Encrypted:%s\n", encrypted);

    char decrypted[strlen(baseStr)];
    encryptDecrypt(encrypted, decrypted);
    printf("Decrypted:%s\n", decrypted);
}

Answer 1

MSVC不支持可变长度数组.一种方法是分配内存.

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

void encryptDecrypt(char *input, char *output) {
    char key[] = {'K', 'C', 'Q'}; //Can be any chars, and any size array
    size_t i;
    for(i = 0; i < strlen(input); i++) {
        output[i] = input[i] ^ key[i % (sizeof(key)/sizeof(char))];
    }
    output[i] = '\0';               // terminate
}

int main () {
    char baseStr[] = "kylewbanks.com";
    size_t len = strlen(baseStr) + 1;

    char *encrypted = malloc(len);
    if(encrypted == NULL) {
        // error handling
    }
    encryptDecrypt(baseStr, encrypted);
    printf("Encrypted:%s\n", encrypted);

    char *decrypted = malloc(len);
    if(decrypted == NULL) {
        // error handling
    }
    encryptDecrypt(encrypted, decrypted);
    printf("Decrypted:%s\n", decrypted);

    free(decrypted);
    free(encrypted);
}

请注意,字符串终止符需要一个额外的字节 - 字符串应该终止.