Encrypt amd Decrypt

EaD.cpp

#include <iostream>
#include <fstream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
using namespace std;

char pass[1024] = "Password";
unsigned sb[12] = {
	643728351, 9846391, 4550585,
	92821797, 3900958, 9274773,
	624294383, 6295738, 40041196,
	697441253, 5648242	, 89595141
};
unsigned rot[8] = { 1, 1, 2, 3, 5, 7, 12, 17 };

char *Encrypt(char *str, int str_size)
{
	int i=0, 
		pass_size = strlen(pass)+1;
	for(i = 0; i <= str_size; i++)
	{
		if(i > pass_size)
		{
			str[i] ^= pass[i % pass_size] ^ sb[i % 12];
			str[i] += pass[i % pass_size] << rot[i % 8];
		}
		else
			str[i] ^= pass[i % pass_size];
	}

	return str;
}

char *Decrypt(char *str, int str_size)
{
	int i=0, 
		pass_size = strlen(pass)+1;
	for(i = 0; i <= str_size; i++)
	{
		if(i > pass_size)
		{
			str[i] -= pass[i % pass_size] << rot[i % 8];
			str[i] ^= pass[i % pass_size] ^ sb[i % 12];
		}
		else
			str[i] ^= pass[i % pass_size];
	}

	return str;
}

int main(int argc, char *argv[])
{
	char *data;
	char filename[1024] = { 0 };
	int file_size = 0, i = 0;

	cout << "Encrypt/Decrypt (e/d) -> ";
	if(getc(stdin) == 'e')
	{
		getchar();
		ifstream readf(argv[1], ios::in|ios::binary);
		ofstream outf;
		cout << "Password =>"; 
		cin >> pass;
		getchar();

		cout << "output encrypt file name =>"; 
		cin >> filename;
		getchar();

		outf.open(filename, std::ios_base::out | std::ios_base::binary);
		file_size = readf.seekg(0, std::ios::end).tellg();
		readf.seekg(0, std::ios::beg);
		data = new char[file_size + 3]();
		readf.read(data, file_size);	
		Encrypt(data, file_size);
		outf.write(data, file_size);

		return 0;
	}
	else
	{
		ifstream readf(argv[1], ios::in|ios::binary);
		ofstream outf;
		cout << "Password =>"; cin >> pass;
		cout << "output decrypt file name =>"; cin >> filename;

		outf.open(filename, std::ios_base::out | std::ios_base::binary);
		file_size = readf.seekg(0, std::ios::end).tellg();
		readf.seekg(0, std::ios::beg);
		data = new char[file_size + 3]();
		readf.read(data, file_size);	
		Decrypt(data, file_size);
		outf.write(data, file_size);

		return 0;
	}
}