AES.h

#pragma once

#include "stdafx.h"
#include "Rijndael_GF.h"

#define KEY_SIZE 128            //128   or 192  or 256
#define NUM_KEYS uint8_t(11)    //11    or 13   or 15
#define KEY_LENGTH (KEY_SIZE/32)

#define ECB 	1	// Electronic CodeBook
#define CBC 	0	// Cipher Block Chaining
#define PCBC 	0	// Propagating Cipher Block Chaining
#define CFB		0	// Cipher Feedback
#define OFB		0	// Output Feedback
#define CTR		0	// Counter

class AES
{
public:
	static unsigned char S_Box[256];
	static unsigned char inverse_S_Box[256];
	static unsigned char rcon[256];
	static unsigned char mul_table[6][256];
	static const unsigned char mul_nums[6];

	/*
	 * Function: encrypt
	 * Parameters:
	 *		unsigned char* message	: Array containing the message to be encrypted
	 *								  also contains the output after encryption. Must
	 *								  be of size as given by the encrypted size funtion.
	 *		int size				: Size to input message to be encrypted in bytes
	 *		unsigned char key		: Encryption Key
	 *		int key_size			: Key Size {128, 192, 256}			- Default: 128
	 *		int mode				: Cipher Block Mode of Operation	- Default: 1
	 *		unsigned char[16] IV	: Initialization Vector				- Default: { 0 }
	 *
	 * Performs AES encryption on the entire messgae block supplied to it using the
	 * key and key_size specified as the input and in the block cipher mode based on
	 * the input parameter. Some modes require an Initialization Vector and it too
	 * must be provided.
	 * If the mode to be used does not require an initialization vector then the
	 * parameter need not be provided.
	 *
	 * Modes Table
	 * Mode No.	Mode Name				Mode Code
	 *	0		Electronic CodeBook		ECB
	 *	1		Cipher Block Chaining	CBC
	 *	2		Propagating CBC			PCBC
	 *	3		Cipher Feedback			CFB
	 *	4		Output Feedback			OFB
	 *	5		Counter					CTR
	*/
	void encrypt(unsigned char* message, int size);

	/*
	* Function: decrypt
	* Parameters:
	*		unsigned char* message	: Array containing the message to be decrypted
	*								  and also contains the output after decrytion
	*		int size				: Size to input message in bytes
	*		unsigned char key		: Encryption Key
	*		int key_size			: Key Size {128, 192, 256}			- Default: 128
	*		int mode				: Cipher Block Mode of Operation	- Default: 1
	* Returns:
	*		int decrypted_size		: The size of the decryted output stored in the same
	*								  input message array
	* Performs AES decryption on the entire messgae block supplied to it using the
	* key and key_size specified as the input and in the block cipher mode based on
	* the input parameter. No initialization vector is necessary assuming the encrypted
	* message was created by the encrypt function of this AES class
	*
	* Modes Table
	* Mode No.	Mode Name				Mode Code
	*	0		Electronic CodeBook		ECB
	*	1		Cipher Block Chaining	CBC
	*	2		Propagating CBC			PCBC
	*	3		Cipher Feedback			CFB
	*	4		Output Feedback			OFB
	*	5		Counter					CTR
	*/
	void decrypt(unsigned char*, int);

	/*
	* Function: encrypt_size
	* Parameters:
	*		int size	: Size of message to be encrypted
	*		int mode	: Mode of encrytion
	* Returns:
	*		int encrypted_size	: Size of the encrypted output
	*
	* The function provides the size of the output
	* after the encryption is performed on a messgage with
	* length equal to the parameter size and using the mode
	* specified in the mode parameter
	*
	* The array size of the input to the encrypt function
	* must be at least the output of this function
	*/
	static int encrypt_size(int, int);

	AES(unsigned char *key, bool encrypt, uint64_t *size, unsigned char *metadata);
	~AES();
public:

	unsigned char prev_data[16];
	unsigned char round_keys[NUM_KEYS][16];

	static void generate_S_Box();
	static void generate_rcon();
	static void generate_mul_tables();
	static void Rijndael_Key_Core(unsigned char*, uint8_t);
	static void expand_key(unsigned char*, unsigned char[][16]);

	static void subBytes(unsigned char[4][4]);
	static void inverseSubBytes(unsigned char[4][4]);

	static void shiftRows(unsigned char[4][4]);
	static void inverseShiftRows(unsigned char[4][4]);

	static void mixColumns(unsigned char[4]);
	static void inverseMixColumns(unsigned char[4]);

	static void round_encrypt(unsigned char[4][4], unsigned char[16]);
	static void round_encrypt_last(unsigned char[4][4], unsigned char[16]);

	static void round_decrypt(unsigned char[4][4], unsigned char[16]);
	static void round_decrypt_first(unsigned char[4][4], unsigned char[16]);

	void encrypt_block(unsigned char[4][4]);
	void decrypt_block(unsigned char[4][4]);
	static void int_to_array(uint64_t, unsigned char*);
};