kernel.h

来自「RC4加解密算法~~~~~~ 密码学课程设计」· C头文件 代码 · 共 41 行

#include <string.h>

#ifndef KERNEL_H
#define KERNEL_H

unsigned char S[256];

void Produce_S(char *key, int keylen)
{
	int i, j;
	unsigned char T[256];
	for(i = 0; i < 256; i++)
	{
		S[i] = i;
		T[i] = key[i % keylen];
	}
	for(i = 0, j = 0; i < 256; i++)
	{
	unsigned char tmp;
		j = (j + S[i] + T[i]) % 256;
		tmp = S[i];
		S[i] = S[j];
		S[j] = tmp;
	}
}

 unsigned char Produce_k(int *i, int *j)
{
   unsigned	char tmp, t, k;
	*i = (*i + 1) % 256;
	*j = (*j + S[*i]) % 256;
	tmp = S[*i];
	S[*i] = S[*j];
	S[*j] = tmp;
	t = (S[*i] + S[*j]) % 256;
	k = S[t];
	return k;
}


#endif