///////////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2008-2010 Artyom Beilis (Tonkikh) <artyomtnk@yahoo.com>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
///////////////////////////////////////////////////////////////////////////////
#define CPPCMS_SOURCE
#include "hmac_encryptor.h"
#include "md5.h"
#include <time.h>
#include <stdlib.h>
#include <string.h>
#include <cppcms/crypto.h>
#include <cppcms/cppcms_error.h>
namespace cppcms {
namespace sessions {
namespace impl {
hmac_factory::hmac_factory(std::string const &algo,crypto::key const &k) :
algo_(algo),
key_(k)
{
}
std::auto_ptr<encryptor> hmac_factory::get()
{
std::auto_ptr<encryptor> ptr;
ptr.reset(new hmac_cipher(algo_,key_));
return ptr;
}
hmac_cipher::hmac_cipher(std::string const &hash_name,crypto::key const &k) :
key_(k),
hash_(hash_name)
{
if(key_.size() < 16) {
throw cppcms_error("The key legth is too small, use at leaset the key of 16 bytes/32 hexadecimal digits");
}
}
std::string hmac_cipher::encrypt(std::string const &plain)
{
crypto::hmac md(hash_,key_);
size_t message_size = plain.size();
size_t digest_size = md.digest_size();
size_t cipher_size = message_size + digest_size;
std::vector<char> data(cipher_size,0);
md.append(plain.c_str(),plain.size());
memcpy(&data[0],plain.c_str(),plain.size());
md.readout(&data[message_size]);
return std::string(&data[0],cipher_size);
}
bool hmac_cipher::decrypt(std::string const &cipher,std::string &plain)
{
crypto::hmac md(hash_,key_);
size_t cipher_size = cipher.size();
size_t digest_size = md.digest_size();
if(cipher_size < digest_size)
return false;
size_t message_size = cipher_size - digest_size;
md.append(cipher.c_str(),message_size);
std::vector<char> mac(digest_size,0);
md.readout(&mac[0]);
bool ok = memcmp(&mac[0],cipher.c_str() + message_size,digest_size) == 0;
memset(&mac[0],0,digest_size);
if(ok) {
plain = cipher.substr(0,message_size);
return true;
}
return false;
}
} // impl
} // sessions
} // cppcms
