picoCTF

Read_The_Manual.js

//Import the request module, used to pull the manual from pico's site
var request = require('request');

//Request the manual
request('https://picoctf.com/problems/manual.txt', function (error, response, body) {

  //Make sure we were actaully successful
	if (!error && response.statusCode == 200) {

		console.log(crypt(body, parseInt(process.argv[2])));

	}

});

//Encrypt or Decrypt a input given a key
function crypt(input, key) {
	var output = "";
	for (var i = 0; i < input.length; i++) {
		var c = input.charCodeAt(i);
		if      (c >= 65 && c <=  90) output += String.fromCharCode((c - 65 + key) % 26 + 65);  // Uppercase
		else if (c >= 97 && c <= 122) output += String.fromCharCode((c - 97 + key) % 26 + 97);  // Lowercase
		else                          output += input.charAt(i);  // Copy
	}
	return output;
}