c - 字节异或的一些问题

发布于 2024-10-31 15:33:05 字数 265 浏览 7 评论 0原文

我必须在 2 字节缓冲区上进行一些二进制异或。一个是编码密钥，另一个是编码值。

目前我的代码如下所示：

BYTE key[]={"somekey"}
BYTE value[]={"somevalue"};

for(i= 0; i < vallLength; i++)
    {
        valBuf[i] = value[i] ^ key[i % keyLength];
    }

这对我不起作用。我做错了什么？

原文

I have to make some binary xor on 2 byte buffers. one is an encoding key, the other the encoded value.

at the moment my code looks like this:

BYTE key[]={"somekey"}
BYTE value[]={"somevalue"};

for(i= 0; i < vallLength; i++)
    {
        valBuf[i] = value[i] ^ key[i % keyLength];
    }

this does not work for me. what am i doing wrong?

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甜心小果奶 2024-11-07 15:33:05

好吧，这很糟糕，但我想编写一些简单的代码来进行更改。

#include <stdio.h>

char key[] = "This is a fancy key.";
char text[] = "Encrypt this extremely long plaintext.";
#define KEY_LEN (sizeof(key))
#define TXT_LEN (sizeof(text))

void crypt(char *key, char *plaintext, char *ciphertext, int keyLen, int ptLen)
{    
    int idx;
    for (idx = 0; idx < ptLen; idx++)
    {
        ciphertext[idx] = plaintext[idx] ^ key[idx % keyLen];
    }
}

int main()
{
    printf("Plaintext before:\n\t%s\n", text);
    crypt(key, text, text, KEY_LEN, TXT_LEN);
    printf("Plaintext after:\n\t%s\n", text);
    crypt(key, text, text, KEY_LEN, TXT_LEN);
    printf("Plaintext after after:\n\t%s\n", text);
    return 0;
}

无论如何，这个问题注定要结束，所以将其发布在这里不会造成太大伤害。

Alright, this is terrible, but I felt like writing some easy code for a change.

#include <stdio.h>

char key[] = "This is a fancy key.";
char text[] = "Encrypt this extremely long plaintext.";
#define KEY_LEN (sizeof(key))
#define TXT_LEN (sizeof(text))

void crypt(char *key, char *plaintext, char *ciphertext, int keyLen, int ptLen)
{    
    int idx;
    for (idx = 0; idx < ptLen; idx++)
    {
        ciphertext[idx] = plaintext[idx] ^ key[idx % keyLen];
    }
}

int main()
{
    printf("Plaintext before:\n\t%s\n", text);
    crypt(key, text, text, KEY_LEN, TXT_LEN);
    printf("Plaintext after:\n\t%s\n", text);
    crypt(key, text, text, KEY_LEN, TXT_LEN);
    printf("Plaintext after after:\n\t%s\n", text);
    return 0;
}

This question's destined for closure anyway, so it can't hurt too much to post it here.

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花开柳相依 2024-11-07 15:33:05

数组“key”和“value”的长度相同吗？我不确定您正在寻找的结果，但您可能只想循环较短的长度，然后将较长的数组值填充到 ^ 答案。

BYTE* xx = new BYTE[SIZEX];
BYTE* yy = new BYTE[SIZEY];

int nCount = Min(xx.Length(), yy.Length());
BYTE* answer = new BYTE[Max(xx.Length(), yy.Length())];
for(int ii=0; ii<nCount; ++ii)
    answer[ii] = xx[ii] ^ y[ii];

BYTE* zz;
if(xx.Length() > yy.Length())
    zz = xx;
else
    zz = yy;

for(int ii=nCount; ii<Max(xx.Length(), yy.Length()); ++ii)
    answer[ii] = zz[ii];

Are the arrays "key" and "value" the same length? I'm not sure of the result you are looking for, but you might want to ONLY loop over the shorter length, then pad the longer array values to the ^ answer.

BYTE* xx = new BYTE[SIZEX];
BYTE* yy = new BYTE[SIZEY];

int nCount = Min(xx.Length(), yy.Length());
BYTE* answer = new BYTE[Max(xx.Length(), yy.Length())];
for(int ii=0; ii<nCount; ++ii)
    answer[ii] = xx[ii] ^ y[ii];

BYTE* zz;
if(xx.Length() > yy.Length())
    zz = xx;
else
    zz = yy;

for(int ii=nCount; ii<Max(xx.Length(), yy.Length()); ++ii)
    answer[ii] = zz[ii];

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