信息安全:OpenSSL之RC4加密简单示例

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RC4

RC4是流密码算法,流算法以密钥作为种子产生密钥流,然后明文比特流和密钥流进行异或以实现加密.

RC4加密算法密钥长度可变,没有填充的麻烦.

函数

OpenSSL中RC4加密算法主要有两个函数,在openssl/rc4.h中找到.如下:

void RC4_set_key(RC4_KEY *key,int len,const unsigned char *data);

void RC4(RC4_KEY *key,size_t len,const unsigned char *indata,unsigned char *outdata);

示例

#include <stdlib.h>#include <stdio.h>#include <string.h>#include <openssl/rc4.h>int main(int argc,char* argv[]){  RC4_KEY key;  unsigned char *data="Hello,World!!";  int length=strlen(data);  RC4_set_key(&key,length,data);//设置密钥  unsigned char *indata="This is plain text !!!!";  int len=strlen(indata);//  printf("len=%d\n",len);  unsigned char *outdata;//分配密文空间  outdata=(unsigned char *)malloc(sizeof(unsigned char)*(len+1));  memset(outdata,0,len+1);//初始为0  printf("\tindata=%s\n",indata);  RC4(&key,strlen(indata),indata,outdata);//加密明文  printf("\toutdata=%s\n",outdata);  //printf("strlen(outdata)=%d\n",strlen(outdata));  unsigned char *plain;//分配明文空间  plain=(unsigned char *)malloc(sizeof(unsigned char)*(len+1));  memset(plain,0,len+1);//初始化为0  RC4_set_key(&key,length,data);//重新设置密钥  RC4(&key,strlen(outdata),outdata,plain);//解密密文  printf("\tplain=%s\n",plain);//  printf("strlen(plain)=%d\n",strlen(plain)); return 0;}

运行结果

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