PHP's M_CRYPT in C Environment

ComminCrypto.h

/////////////////////////
// Base64.h

#ifndef BASE64_H
#define BASE64_H

#include <string>
#include <vector>

class Base64
{
public:
    static std::string encode( const unsigned char * p_buffer, size_t p_size );

    static std::string encode( const std::string & p_string );

    static std::string encode( const std::vector< unsigned char > & p_buffer );

    static std::string decode( const std::string & p_input );

    static void decode( const std::string & p_input, std::vector< unsigned char > & p_output );
};

#endif // BASE64_H

/////////////////////////
// Base64.cpp

//#include "Base64.h"

#include <openssl/evp.h>

using namespace std;

string Base64::encode( const unsigned char * p_buffer, size_t p_size )
{
    unsigned char * output( new unsigned char[ p_size * 4 / 3 + 4 ] );

    size_t outputLength( EVP_EncodeBlock( output, p_buffer, static_cast< int >( p_size ) ) );

    string ret( reinterpret_cast< char * >( output ), outputLength );

    delete [] output;

    return ret;
}

string Base64::encode( const string & p_string )
{
    return Base64::encode( reinterpret_cast< const unsigned char * >( p_string.c_str() ), p_string.size() );
}

string Base64::encode( const vector< unsigned char > & p_buffer )
{
    return Base64::encode( &p_buffer[ 0 ], p_buffer.size() );
}

void Base64::decode( const string & p_input, vector< unsigned char > & p_output )
{
    p_output.resize( p_input.length() * 3 / 4 );

    size_t outputLength( EVP_DecodeBlock( &p_output[ 0 ], reinterpret_cast< const unsigned char * >( p_input.c_str() ), static_cast< int >( p_input.size() ) ) );

    size_t length( p_input.length() );

    if ( p_input[ length - 2 ] == '=' )
    {
        outputLength -= 2;
    }
    else if ( p_input[ length - 1 ] == '=' )
    {
        outputLength--;
    }

    p_output.resize( outputLength );
}

string Base64::decode( const string & p_input )
{
    vector< unsigned char > output;
    Base64::decode( p_input, output );
    return reinterpret_cast< const char * >( &output[ 0 ] );
}

/////////////////////////
// main.cpp

#include <iostream>
#include <string>
#include <regex>

#include <openssl/evp.h>
#include <mcrypt.h>

#define MCRYPT_MODE_CBC "cbc"

using namespace std;

string md5( const string & p_string )
{
    EVP_MD_CTX mdContext;
    const EVP_MD * md;
    unsigned int outputLength;
    unsigned char output[ 16 ];

    OpenSSL_add_all_digests();

    if ( !( md = EVP_get_digestbyname( "MD5" ) ) )
    {
        throw std::runtime_error( "Unable to init MD5 digest." );
    }

    EVP_MD_CTX_init( &mdContext );
    EVP_DigestInit_ex( &mdContext, md, 0 );
    EVP_DigestUpdate( &mdContext, p_string.c_str(), p_string.length() );
    EVP_DigestFinal_ex( &mdContext, output, &outputLength );
    EVP_MD_CTX_cleanup( &mdContext );

    char outputString[ sizeof( output ) * 2 + 1 ];

    for ( int i( 0 ); i < sizeof( output ); ++i )
    {
        snprintf( outputString + i * 2, 2 + 1, "%02x", output[ i ] );
    }

    return outputString;
}

string trimString( const string & p_string )
{
    string ret( p_string );

    regex functionRegex( "\\s*(.*)\\s*", regex_constants::icase );
    smatch matches;

    if ( regex_search( p_string, matches, functionRegex ) )
    {
        ret = matches[ 1 ].str();
    }

    return ret;
}

void mcrypt_encrypt( vector< unsigned char > & p_output, const char * p_cryptEngine, const string & p_key, const vector< unsigned char > & p_input, const char * p_mode, const string & p_iv )
{
    MCRYPT td = mcrypt_module_open( ( char * )p_cryptEngine, 0, ( char * )p_mode, 0 );

    if ( td == MCRYPT_FAILED )
    {
        throw std::runtime_error( "can't init mcrypt" );
    }

    if ( mcrypt_generic_init( td, ( char * )p_key.c_str(), mcrypt_enc_get_key_size( td ), ( char * )p_iv.c_str() ) < 0 )
    {
        throw std::runtime_error( "can't setup key/iv" );
    }

    p_output.reserve( p_input.size() );
    copy( p_input.begin(), p_input.end(), back_inserter( p_output ) );

    mcrypt_generic( td, ( void * )&p_output[ 0 ], (int)p_output.size() );

    mcrypt_generic_end( td );
}

void mcrypt_decrypt( vector< unsigned char > & p_output, const char * p_cryptEngine, const string & p_key, const vector< unsigned char > & p_input, const char * p_mode, const string & p_iv )
{
    MCRYPT td = mcrypt_module_open( ( char * )p_cryptEngine, 0, ( char * )p_mode, 0 );

    if ( td == MCRYPT_FAILED )
    {
        throw std::runtime_error( "can't init mcrypt" );
    }

    if ( mcrypt_generic_init( td, ( char * )p_key.c_str(), mcrypt_enc_get_key_size( td ), ( char * )p_iv.c_str() ) < 0 )
    {
        throw std::runtime_error( "can't setup key/iv" );
    }

    p_output.reserve( p_input.size() );
    copy( p_input.begin(), p_input.end(), back_inserter( p_output ) );

    mdecrypt_generic( td, ( void * )&p_output[ 0 ], (int)p_output.size() );

    mcrypt_generic_end( td );
}

string encrypt_decrypt( const string & action, const string & p_string )
{
    string output = "";

    string key = "mykeyhereblah";
    string iv = md5( md5( key ) );

    vector< unsigned char > cipherText, plainText;

    if ( action == "encrypt" )
    {
        copy( p_string.begin(), p_string.end(), back_inserter( plainText ) );

        mcrypt_encrypt( cipherText, MCRYPT_RIJNDAEL_256, md5( key ), plainText, MCRYPT_MODE_CBC, iv );

        output = Base64::encode( cipherText );
    }
    else if ( action == "decrypt" )
    {
        Base64::decode( p_string, cipherText );
        mcrypt_decrypt( plainText, MCRYPT_RIJNDAEL_256, md5( key ), cipherText, MCRYPT_MODE_CBC, iv );

        output = string( ( char* )&plainText[ 0 ], plainText.size() );
        output = trimString( output );
    }

    return output;
}

int main( int argc, char * argv[] )
{
    string plainText = "the book is on the table!";
    string cipherText = encrypt_decrypt( "encrypt", plainText );

    cout << "plain text: " << plainText << endl;
    cout << "cipher text: " << cipherText << endl;
    cout << "back to: " << encrypt_decrypt( "decrypt", cipherText ) << endl;
    cout << endl;
    cout << "your sample: " << encrypt_decrypt( "decrypt", "2Fa9cICuUFa/UnmAAa5FjXZK4ht9q3cN2qgk1pCvDSs=" ) << endl;

    return 0;
}