C++ Failproof xor 加解密源代码

C++ Failproof xor 加解密源代码

/* All of the XOR encryption algorithms I encountered on the web were faulty on
 * some keys/inputs using binary read & write both for files and chars is
 * crucial */
 
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
 
#define MAX 512 // max key length
 
void xorenc(char *inname, char *outname, char *key);
 
int main(int argc, char **argv)
{
    char input[MAX], *key;
 
    if(argc != 3) // check the arguments
    {
        printf("ERROR: invalid arguments\n\n");
        printf("Usage:\n");
        printf("%s [input] [output]\n", argv[0]);
        return EXIT_FAILURE;
    }
     
    /* get the key */
    printf("Key plz: ");
    fgets(input, MAX, stdin);
    key = malloc(strlen(input) + 1);
    strcpy(key, input);
     
    xorenc(argv[1], argv[2], key);
     
    free(key);
    return 0;
}
 
void xorenc(char *inname, char *outname, char *key)
{
    FILE *input, *output;
    char c[1];
    int i, k;
     
    input = fopen(inname, "rb");
    output = fopen(outname, "wb");
     
    k = strlen(key);
    i = 0;
    while((fread(c, 1, 1, input)) != 0)
    {
        c[0] ^= key[i++]; // xor the input file's char with key's char
        fwrite(c, 1, 1, output); // write the (en/de)crypted char to output
        if(i == k) i = 0; // rewind the key if input is longer than it
    }
     
    fclose(input);
    fclose(output);