aes加密

    aes加密算法，工作中能用就没再怎么深入研究，对于aes的几种填充方式还不知道是怎么设置的，下面的openssl代码默认的是用空格填充。对这个有心得的朋友，留言板永远为你敞开。

#include <stdio.h>
#include <string.h>
#include "stdafx.h"
#include <openssl/aes.h>
#define INTERFACE "eth0"
#define PAD_SIZE 32
/*
 *需要密钥key[16+1]，向量iv1[16+1]，明文pt1[]
*/
void hextoasii(unsigned char *bytes, int byteNum, char *strAsii);

//----------------------------------------------------------
int aes_test(void)
{
    
    unsigned char key[] = ")*^&$*kdjfkdjfjdsjfska!*&^%$#@"; // 128bits key (应该是真正的随机数才好)

    char pt1[] = "aaaaaaaaaaaaaaaaab"; // 明文, 16位的时候 成功。

    pt1[5] = 0x0;
    
    char ct[1000] = {0}; // 密文

    char pt2[1000]={0}; // 解密后的明文

    AES_KEY k;
    
    int ilen=sizeof(pt1);
    int ctLen = (ilen%16==0)?ilen:(ilen/16+1)*16;
    //|bc~!f947j*$m_op

    unsigned char iv1[16+1] = {"|bc~!f947j*$m_op"}; // 16+1，加密用

    unsigned char iv2[16+1] = {"|bc~!f947j*$m_op"}; // 16+1，解密用

    
    
    int i,j;
    AES_set_encrypt_key(key, 16*16, &k);
 
 /*
 void AES_cbc_encrypt(
 const unsigned char *in,
 unsigned char *out,
 const unsigned long length, //in 的长度
 const AES_KEY *key, //it will be changed during the encrypt&decrypt process, so it required to be reset each time
 unsigned char *ivec, //向量
 const int enc);
 */
     AES_cbc_encrypt((unsigned char*)pt1, (unsigned char*)ct, ilen, &k, (unsigned char*)iv1, AES_ENCRYPT);
 
     printf("encrypt:%s\n", ct);
     FILE *fp1 = fopen("aes_encrypt.txt", "w");
     fwrite(ct,sizeof(unsigned char),ctLen, fp1);
     fflush(fp1);
 
 
     char strAsii[1000]={0};
     hextoasii((unsigned char*)ct, ctLen, strAsii);
     printf("\n%s\n", strAsii);
 
 //memset(pt2, 0, 33);

 
     AES_set_decrypt_key(key, 16*16, &k);
     AES_cbc_encrypt((unsigned char*)ct, (unsigned char*)pt2, ctLen, &k, (unsigned char*)iv2, AES_DECRYPT);
 
     printf("before: %s\n", pt1);
     printf("after : %s\n", pt2);
     if (memcmp(pt1, pt2, ilen)==0)
         puts("AES CBC mode ok");
     else puts("AES CBC mode err");
    
    return 0;
}
//-----------------------------------------------------------
char* AESDecrypt (
      char* strEncryptDes,
      const char* strUnEncryptSrc
      )
{
     unsigned char cipher[10000] = {0}; // 密文

     unsigned char iv1[16+1] = {"|bc~!f947j*$m_op"}; // 16+1，向量

     unsigned char strEncryptKey[] = ")*^&$*kdjfkdjfjdsjfska!*&^%$#@"; // 128bits key (应该是真正的随机数才好)

     AES_KEY k;
     int ilen=strlen(strUnEncryptSrc);
     int ctLen = ilen/2;

     int i=0, nCipherHex=0;
     char strAsii[5];
     for(i=0; i<ctLen; i++)
     {
         memset(strAsii, 0, 5);
         memcpy(strAsii, strUnEncryptSrc, 2);
         sscanf(strAsii,"%X", &nCipherHex);
         cipher[i] = nCipherHex;
         strUnEncryptSrc += 2;
     }

     AES_set_decrypt_key(strEncryptKey, 16*16, &k);
     AES_cbc_encrypt((unsigned char*)cipher, (unsigned char*)  strEncryptDes, ctLen, &k, (unsigned char*)iv1, AES_DECRYPT);
 //hextoasii(cipher, ctLen, strEncryptDes);

 return strEncryptDes;
}

//-----------------------------------------------------------
char* AESEncrypt ( unsigned char* strUnEncryptSrc, unsigned char* strEncryptDes, int ilen)
{
     //string strEncryptDes;

      unsigned char cipher[10000] = {0}; // 密文

      unsigned char iv1[16+1] = {"|bc~!f947j*$m_op"}; // 16+1，向量 

      unsigned char strEncryptKey[] = ")*^&$*kdjfkdjfjdsjfska!*&^%$#@"; // 128bits key (应该是真正的随机数才好)

      AES_KEY k;
      int i=0;
      char strAsii[5];
 
      //int ilen=strUnEncryptSrc.length(); 

      int ctLen = (ilen%16==0)?ilen:(ilen/16+1)*16; 
 
      AES_set_encrypt_key((unsigned char*)strEncryptKey, 16*16, &k);
 
 /*
 void AES_cbc_encrypt(
 const unsigned char *in, //明文
 unsigned char *out, //密文
 const unsigned long length, //in 的长度
 const AES_KEY *key, //it will be changed during the encrypt&decrypt process, so it required to be reset each time
 unsigned char *ivec, //向量
 const int enc);
 */
      AES_cbc_encrypt(strUnEncryptSrc, (unsigned char*)cipher, ilen, &k, (unsigned char*)iv1, AES_ENCRYPT);
 
 
      for(i=0; i<ctLen; i++)
      {
            memset(strAsii, 0, 5);
            sprintf(strAsii,"%02X", cipher[i]);
            memcpy(&strEncryptDes[i*2], strAsii, 2);
      }     
      //hextoasii(cipher, ctLen, strEncryptDes);

      return (char*)strEncryptDes;
}
//-----------------------------------------------------------
void aes_hex(void)
{
      char str[] = "hello world\n";
      char strAes[10000] = {0};
      char strUnAes[10000]={0};
      AESEncrypt ((unsigned char*)str, (unsigned char*)strAes, sizeof(str));
      AESDecrypt (strUnAes,strAes);
      printf("\n");
      printf(str);
      printf(strUnAes);
}
//----------------------------------------------------------
void hextoasii(unsigned char *bytes, int byteNum, char *strAsii)
{
    int i=0;
    for(i=0; i<byteNum; i++)
    {
        sprintf(strAsii,"%02X", bytes[i]);
        strAsii += 2;
    }
    *strAsii = '\n';
}