crypter.cpp
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#include "crypter.h"
// std
#include <iomanip>
#include <memory>
#include <sstream>
#include <stdexcept>
#include <system_error>
// openssl
#include <openssl/evp.h>
// osdev::components
#include "log.h"
#include "scopeguard.h"
using namespace osdev::components;
namespace {
const EVP_MD* getAlgo( Crypter::AlgorithmEnum algo )
{
switch ( algo )
{
case Crypter::AlgorithmEnum::MD0:
return EVP_md_null();
case Crypter::AlgorithmEnum::MD2:
// return EVP_md2();
case Crypter::AlgorithmEnum::MD5:
return EVP_md5();
case Crypter::AlgorithmEnum::MDC2:
// deprecated.
// md = EVP_mdc2();
return EVP_md_null();
case Crypter::AlgorithmEnum::SHA1:
return EVP_sha1();
case Crypter::AlgorithmEnum::SHA224:
return EVP_sha224();
case Crypter::AlgorithmEnum::SHA256:
return EVP_sha256();
case Crypter::AlgorithmEnum::SHA384:
return EVP_sha384();
case Crypter::AlgorithmEnum::SHA512:
return EVP_sha512();
case Crypter::AlgorithmEnum::RIPEMD160:
return EVP_ripemd160();
}
throw std::invalid_argument("Crypto algorithm not found.");
}
} // anonymous
Crypter::Crypter()
{
}
std::string Crypter::encrypt( const std::string& message, Crypter::AlgorithmEnum algo )
{
// Create the environment
auto md = getAlgo(algo);
#if OPENSSL_VERSION_NUMBER >= 0x1010008fL
auto mdContext = std::unique_ptr<EVP_MD_CTX, decltype(&EVP_MD_CTX_free)>(
EVP_MD_CTX_create(),
[](EVP_MD_CTX* ptr){EVP_MD_CTX_free(ptr);});
// This will call EVP_cleanup if the guard goes out of scope.
ScopeGuard oGuard( &EVP_PBE_cleanup );
#else
auto mdContext = std::unique_ptr<EVP_MD_CTX, decltype(&EVP_MD_CTX_destroy)>(
EVP_MD_CTX_create(),
[](EVP_MD_CTX* ptr){EVP_MD_CTX_destroy(ptr);});
// This will call EVP_cleanup if the guard goes out of scope.
ScopeGuard oGuard( &EVP_cleanup );
#endif
(void)oGuard; // Satisfy the compiler for unused variables.
auto errorCode = EVP_DigestInit_ex( mdContext.get(), md, NULL );
if( 1 != errorCode )
{
LogError( "[Crypter::encrypt]", std::string( "No encryption digest environment created." ) );
throw std::system_error( errorCode, std::system_category(), "No encryption digest environment created." );
}
// Update the environment with the message
errorCode = EVP_DigestUpdate( mdContext.get(), message.c_str(), message.length() );
if( 1 != errorCode )
{
LogError( "[Crypter::encrypt]", std::string("Digest failed.") );
throw std::system_error( errorCode, std::system_category(), "Digest failed.." );
}
// End the Digest so we can read the crypted message.
unsigned int mdLen;
unsigned char mdValue[EVP_MAX_MD_SIZE];
errorCode = EVP_DigestFinal_ex( mdContext.get(), mdValue, &mdLen );
if( 1 != errorCode )
{
LogError( "[Crypter::encrypt]", std::string("There was an error closing the digest environment.") );
throw std::system_error( errorCode, std::system_category(), "There was an error closing the digest environment." );
}
// If we got here, all went well. We retrieve the crypted message
// through a stringstream : convert to hex, padding and width and return the string.
std::stringstream ss;
for( unsigned int nIndex = 0; nIndex < mdLen; nIndex++ )
{
ss << std::hex << std::setw( 2 ) << std::setfill( '0' ) << static_cast<int>( mdValue[nIndex] );
}
return ss.str();
}