aescryptosystem.h

AES implementation in C++. Input: key file and the file for encryption Output: the crypted file.

#pragma once

//#include "utils.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <io.h>
#include <fcntl.h>

#include <windows.h>
#include <string>
//#include "utils.h"


#define BYTE_SIZE 8
#define CHAR_TO_COMPLETE_TEXT 0

unsigned char gmul(unsigned char a, unsigned char b);

class AESCryptoSystem
{
public:
	typedef unsigned char byte;
	typedef unsigned char word[4];
	typedef byte state[4][4];

private:
	const int m_ciNb; // nr of block collumns;
	int m_iNk; // nr of key collumns;
	int m_iNr; // nr of rounds, base in Nb and Nk;

	byte* m_pKey; // key

	DWORD m_iOriginalTextSize;

	DWORD m_iPlainTextSize;
	byte* m_pPlainText; // input text
	byte* m_pCryptedText; // crypted input text

	DWORD m_iCryptoTextSize;
	byte* m_pCryptoText;
	byte* m_pDecryptedText;

	//state m_state; // current state;
	word* m_pExpandedKey;

public:
	static const byte st_cSBox[256];
	static const byte st_cSBoxInv[256];
	static const byte st_cXtime2SBox[256];
	static const byte st_cXtime3SBox[256];
	static const byte st_cXtime2[256];
	static const byte st_cXtime3[256];
	static const byte st_cXtime9[256];
	static const byte st_cXtimeB[256];
	static const byte st_cXtimeD[256];
	static const byte st_cXtimeE[256];

	static const byte st_cRcon[15];
public:
	AESCryptoSystem(void);
	~AESCryptoSystem(void);

private:
	//void SaveText(const std::string& s, int fileSize, byte* text);
	void ErrorExit(LPTSTR lpszFunction) const;
	void SetFile(const std::string& sFileName, DWORD& fileSize, byte** ppSrcText, byte** ppDstText, bool bIsCryptoText);
	void SaveFile(const std::string& sFileName, DWORD bytesToWrite, const byte* pText, bool bIsCryptedText) const;

	word& operator = (const word& w1);

	void PrintToScreen(const byte* pT, DWORD size);
	void PrintToScreen(const word& w);
	void PrintToScreen(const state& s);
	void PrintToScreenKey(const word* pW);

private:
	void CalculateRoundKey();
	void RotByte(word& w);
	void SubBytes(word& w);

	void Encode(state& currState);
	void AddRoundKey(state& s, const word* key);
	void SubBytes(state& s);
	void ShiftRows(state& s);
	void MixColumns(state& s);

	void Decode(state& currState);
	void InvSubBytes(state& s);
	void InvShiftRows(state& s);
	void InvMixColumns(state& s);

public:
	void SetKeyFile(const std::string& s);
	void SetPlainTextFile(const std::string& s);
	void SetCryptoTextFile(const std::string& s);

	void SaveCryptedTextToFile(const std::string& s);
	void SaveDecryptedTextToFile(const std::string& s);

	void Encrypt();
	void Decrypt();
};