问题描述

C++ openssl aes加密失败

我在使用openssl的aes（cbc）加密字节超过96的字符串后，在解密就会少字符，下面是我写的代码，求大神指点下什么问题,AES一次加密的明文是有长度限制么？
CooloiAES::CooloiAES()
: MSG_LEN(0)
{
for(int i = 0; i < AES_BLOCK_SIZE; i++)
{
key[i] = 32 + i;
}
}

CooloiAES::~CooloiAES()
{

}

std::string CooloiAES::aes_encrypt(std::string msg)
{
int i = msg.size() / 16;
MSG_LEN = ( i + 1 ) * 16;

//MSG_LEN = msg.size() + 16;

char in[MSG_LEN];
char out[MSG_LEN];
memset((char*)in,0,MSG_LEN);
memset((char*)out,0,MSG_LEN);

//strncpy((char*)in,msg.c_str(),msg.size());
//memcpy((char*)in,msg.data(),msg.size());
strcpy((char*)in,msg.c_str());

unsigned char iv[AES_BLOCK_SIZE]; //加密的初始化向量
for(int j = 0; j < AES_BLOCK_SIZE; ++j)
{
    iv[j] = 0;
}

AES_KEY aes;
if(AES_set_encrypt_key((unsigned char*)key, 128, &aes) < 0)
{
    return NULL;
}
size_t len = strlen(in);

std::cout << "LEN ::::: " << len << std::endl;

AES_cbc_encrypt((unsigned char*)in,(unsigned char*)out,len,&aes,iv,AES_ENCRYPT);

std::string encrypt_msg(&out[0],&out[MSG_LEN+16]);
for(int i= 0;out[i];i++){
    printf("%x",(unsigned char)out[i]);
    //std::cout << dstStringTemp[i];
}
std::cout << std::endl;
return encrypt_msg;

}

std::string CooloiAES::aes_decrypt(std::string msg)
{
MSG_LEN = msg.size();

char in[MSG_LEN];
char out[MSG_LEN+16];
memset((char*)in,0,MSG_LEN);
memset((char*)out,0,MSG_LEN+16);

//strncpy((char*)in,msg.c_str(),msg.size());

memcpy((char*)in,msg.data(),msg.size());

for(int i= 0;in[i];i++){
    printf("%x",(unsigned char)in[i]);
    //std::cout << dstStringTemp[i];
}
std::cout << std::endl;

unsigned char iv[AES_BLOCK_SIZE]; //加密的初始化向量
for(int j = 0; j < AES_BLOCK_SIZE; ++j)
{
    iv[j] = 0;
}

AES_KEY aes;
if(AES_set_decrypt_key((unsigned char*)key, 128, &aes) < 0)
{
    return NULL;
}
//int len = msg.size();
size_t len = strlen(in);
AES_cbc_encrypt((unsigned char*)in,(unsigned char*)out,len,&aes,iv,AES_DECRYPT);
std::string decrypt_msg = out;
return decrypt_msg;

}

解决方案

本文转自http://yuanshuilee.blog.163.com/blog/static/21769727520140942826137/

openssl之aes加密（AES_cbc_encrypt 与 AES_encrypt 的编程案例）??
2014-01-09 16:28:26|??分类：

软件安全以及传输 |举报
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续前几天的一篇......
答案就在这里：openssl之aes加密

解决方案二：

受到密钥长度。最好分组加密