DidacticEnc.h

/**************************************************************************
	@file     didacticNet.h
	@author   anian buehler @ letsgoING
**************************************************************************/

#ifndef _DIDACTICENC_
#define _DIDACTICENC_

#include "Arduino.h"

class DidacticEncSymetric
{
	// NEW #define DE_LENGHT_KEY 8

#define MIN_LEN_KEY 5		  // NEW
#define MAX_LEN_KEY 20		  // NEW
#define MAX_LEN_CYPHERTEXT 20 // NEW DE_LENGHT_KEY * 4
#define MAX_LEN_PLAINTEXT 19  // NEW DE_LENGHT_KEY * 4

#define DE_ERROR_NOERROR 1
#define DE_ERROR_KEYLENGHT_LONG -1
#define DE_ERROR_KEYLENGHT_SHORT -2

#define DE_CS_CORRECT true
#define DE_CS_INCORRECT false

private:
	char _bufferCyphertext[MAX_LEN_CYPHERTEXT + 1] = {0};
	char _bufferPlaintext[MAX_LEN_PLAINTEXT + 1] = {0};
	char _key[MAX_LEN_KEY + 1] = {'0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '\0'};

public:
	DidacticEncSymetric();
	~DidacticEncSymetric();

	int setKey(char *);
	void setTestMark(char);

	void crypt(char *, int, char *, char *, int);
	void crypt(char *, char *, char *);
	void crypt(char *, char *);

	void encrypt(char *, int, char *, char *, int);
	void encrypt(char *, char *, char *);
	void encrypt(char *, char *);

	bool decrypt(char *, int, char *, char *, int);
	bool decrypt(char *, char *, char *);
	bool decrypt(char *, char *);
};

class DidacticEncAsymetric
{
#define MAX_NR_OF_PRIMES 48
#define MAX_PRIME_OFFSET 3
#define MAX_LEN_PLAINTEXT 20
#define MAX_LEN_CYPHERTEXT 250

#define DE_CYPHER_SEPARATOR ";"

private:
	const int prime[MAX_NR_OF_PRIMES] = {17, 19, 23, 29, 31, 37,
										 41, 43, 47, 53, 59, 61, 67, 71, 73,
										 79, 83, 89, 97, 101, 103, 107, 109,
										 113, 127, 131, 137, 139, 149, 151, 157,
										 163, 167, 173, 179, 181, 191, 193, 197,
										 199, 211, 223, 227, 229, 233, 239, 241,
										 251}; //, 257, 263, 269, 271, 277, 281};

	char _bufferCyphertext[MAX_LEN_CYPHERTEXT + 1] = {0};

	long _privateKey = 0L;
	long _publicKey = 0L;
	long _rsaModule = 0L;

	int _randomPin = A5;

	void generateRsaKeys(long, long, long &, long &, long &);
	long cryptRsa(long key, long rsaModul, long message);

	long getPrimeWithOffset(long);
	long getPrime();

	// rsa math functions
	long gcd(long, long);				   // basic euclidean algorithm
	long egcd(long, long, long &, long &); // extended euclidean algorithm
	long modPow(long, long, long);		   // modular exponentation

public:
	DidacticEncAsymetric();
	~DidacticEncAsymetric();

	void generateKeys();

	void setRandomSeedPin(int);

	long getPrivateKey();
	long getPublicKey();
	long getRsaModule();

	int encrypt(char *, int, char *, long, long);
	int encrypt(char *, char *, long, long);

	int decrypt(char *, char *, long, long);
};
#endif