AES为Advanced Encryption Standard的缩写,中文名:高级加密标准,在密码学中又称Rijndael加密法,是美国联邦政府采用的一种区块加密标准,用来替代DES。基于std::string实现的C++包装类,使用得应用AES算法十分简单。完整源代码链接:
aes_helper.h头文件
-
// 高级加密标准(Advanced Encryption Standard),
-
// 在密码学中又称Rijndael加密法,是美国联邦政府采用的一种区块加密标准,用来替代DES
-
class CAESHelper
-
{
-
public:
-
// 加密数据块分组长度,必须为128比特(密钥长度可以是128比特、192比特、256比特中的任意一个)
-
static int aes_block_size;
-
-
public:
-
// key 密钥
-
//
-
// 因为AES要求key长度只能为128或192或256比特中的一种,即16字节或24字节或32字节中的一种,
-
// 当key的长度不足16字节时,CAESHelper自动补0足16字节,
-
// 当key的长度间于16字节和24字节时,CAESHelper自动补0足24字节,
-
// 当key的长度间于24字节和32字节时,CAESHelper自动补0足32字节,
-
// 当key的长度超出32字节时,CAESHelper自动截取前32字节作为密钥
-
CAESHelper(const std::string& key);
-
~CAESHelper();
-
-
void encrypt(const std::string& in, std::string* out);
-
void decrypt(const std::string& in, std::string* out);
-
-
private:
-
// flag 为true表示加密,为false表示解密
-
void aes(bool flag, const std::string& in, std::string* out, void* aes_key);
-
-
private:
-
void* _encrypt_key;
-
void* _decrypt_key;
-
std::string _key;
-
};
aes_helper.cpp文件
-
#if MOOON_HAVE_OPENSSL == 1
-
int CAESHelper::aes_block_size = AES_BLOCK_SIZE; // 16
-
#else
-
int CAESHelper::aes_block_size = 0;
-
#endif // MOOON_HAVE_OPENSSL
-
-
static std::string errcode2errmsg(int errcode)
-
{
-
std::string errmsg;
-
-
if (0 == errcode)
-
errmsg = "success";
-
else if (-1 == errcode)
-
errmsg = "userkey is empty";
-
else if (-2 == errcode)
-
errmsg = "length of userkey is invalid";
-
else
-
errmsg = "unknown error";
-
return errmsg;
-
}
-
-
CAESHelper::CAESHelper(const std::string& key)
-
{
-
_encrypt_key = NULL;
-
_decrypt_key = NULL;
-
_key = key;
-
-
const std::string::size_type LEN16 = 16;
-
const std::string::size_type LEN24 = 24;
-
const std::string::size_type LEN32 = 32;
-
const std::string::size_type len = key.size();
-
if ((len != LEN16) &&
-
(len != LEN24) &&
-
(len != LEN32))
-
{
-
if (len < LEN16)
-
_key.resize(LEN16);
-
else if (len < LEN24)
-
_key.resize(LEN24);
-
else if (len < LEN32)
-
_key.resize(LEN32);
-
else
-
_key.resize(LEN32);
-
}
-
}
-
-
CAESHelper::~CAESHelper()
-
{
-
#if MOOON_HAVE_OPENSSL == 1
-
delete (AES_KEY*)_encrypt_key;
-
delete (AES_KEY*)_decrypt_key;
-
#endif // MOOON_HAVE_OPENSSL
-
}
-
-
void CAESHelper::encrypt(const std::string& in, std::string* out)
-
{
-
#if MOOON_HAVE_OPENSSL == 1
-
if (NULL == _encrypt_key)
-
{
-
_encrypt_key = new AES_KEY;
-
-
const int errcode = AES_set_encrypt_key((const unsigned char*)(_key.data()), (int)(_key.size()*8), (AES_KEY*)_encrypt_key);
-
if (errcode != 0) // 理论上不会返回非0,因为构造函数已经处理好了key的长度
-
{
-
delete (AES_KEY*)_encrypt_key;
-
_encrypt_key = NULL;
-
THROW_EXCEPTION(errcode2errmsg(errcode), errcode);
-
}
-
}
-
-
aes(true, in, out, _encrypt_key);
-
#endif // MOOON_HAVE_OPENSSL
-
}
-
-
void CAESHelper::decrypt(const std::string& in, std::string* out)
-
{
-
#if MOOON_HAVE_OPENSSL == 1
-
if (NULL == _decrypt_key)
-
{
-
_decrypt_key = new AES_KEY;
-
-
const int errcode = AES_set_decrypt_key((const unsigned char*)(_key.data()), (int)(_key.size()*8), (AES_KEY*)_decrypt_key);
-
if (errcode != 0) // 理论上不会返回非0,因为构造函数已经处理好了key的长度
-
{
-
delete (AES_KEY*)_decrypt_key;
-
_decrypt_key = NULL;
-
THROW_EXCEPTION(errcode2errmsg(errcode), errcode);
-
}
-
}
-
-
aes(false, in, out, _decrypt_key);
-
#endif // MOOON_HAVE_OPENSSL
-
}
-
-
void CAESHelper::aes(bool flag, const std::string& in, std::string* out, void* aes_key)
-
{
-
#if MOOON_HAVE_OPENSSL == 1
-
AES_KEY* aes_key_ = (AES_KEY*)aes_key;
-
-
std::string in_tmp = in;
-
if (in.size() % AES_BLOCK_SIZE != 0)
-
{
-
std::string::size_type tmp_size = in.size() + (AES_BLOCK_SIZE - in.size() % AES_BLOCK_SIZE);
-
in_tmp.resize(tmp_size);
-
}
-
-
const char* in_p = in_tmp.data();
-
out->resize(in_tmp.size());
-
char* out_p = const_cast<char*>(out->data());
-
-
for (std::string::size_type i=0; i<in.size(); i+=AES_BLOCK_SIZE)
-
{
-
char out_tmp[AES_BLOCK_SIZE];
-
-
if (flag)
-
AES_encrypt((const unsigned char*)(in_p), (unsigned char*)(out_tmp), aes_key_);
-
else
-
AES_decrypt((const unsigned char*)(in_p), (unsigned char*)(out_tmp), aes_key_);
-
-
in_p += AES_BLOCK_SIZE;
-
memcpy(out_p+i, out_tmp, AES_BLOCK_SIZE);
-
}
-
#else
-
*out = '\0'; // 需要加上这一句,不然难区分HAVE_OPENSSL值是否为1或不为1的情况
-
#endif // MOOON_HAVE_OPENSSL
-
}
阅读(48621) | 评论(1) | 转发(0) |