EasyCrypt
EasyCrypt for JavaScript
EasyCrypt is a port of an encryption algorithm developed in college. It’s by no means the best or most ideal means of encryption (at least not when compared to RSA, AES, SHA1, Blowfish etc), but it’s a basic encryption algorithm developed for simply showing students and adults alike how to go about writing their own encryption algorithm.
The encryption algorithm is equipped with a encrypt/decrypt function. EasyCrypt is a substitution cipher (like ROT13 a simple variant of the Caesar Cipher used by Julius Ceasar to communicate with his generals)
The code that will be shown below has the following configuration. Customization
var shift = 3;
var cipher = "@)*%/~^!?z";
Notice the shift value of 3, which simply means that when the value is converted to character code move it 3 values up.
e.g. 72 (H) would be 75 (K). The cipher is used to obfuscate/encrypt the entered text making it useless to an intruder or person without with proper cipher.
NB: This cipher is for teaching purposes or simple encryption.
Complete code below:
/**
* Created by JetBrains PhpStorm.
* User: ferron
* Date: 1/3/12
* Time: 5:01 PM
* To change this template use File | Settings | File Templates.
*/
/*
* CopyLeft (c) 2009 Ferron Hanse All Rights Reserved.
*
* This software is made available under the terms of the "GPL License"
* A copy of this license is included with this source distribution
* in "license.txt" and is also available at:
* http://www.gnu.org/copyleft/gpl.html
*
* Last Update : 07 September 2009
* Converted to Java
* JSLint 100%
*
* Welcome to any suggestion : ferronrsmith@gmail.com
*/
var shift = 3;
var cipher = "@)*%/~^!?z";
var EasyCrypt = {
encrypt : function (data) {
"use strict";
var encrypted = "", i, compared, j, temp = "";
for (i = 0; i < data.length; i += 1) {
compared = data.charCodeAt(i) + shift;
if (compared < 100) {
if (compared < 10) {
encrypted += "00" + compared.valueOf();
} else {
encrypted += "0" + compared.valueOf();
}
} else {
encrypted += compared.valueOf();
}
}
for (j = 0; j < encrypted.length; j += 1) { //substitution
switch (encrypted.charAt(j)) {
case '0': temp += cipher.charAt(0); break;
case '1': temp += cipher.charAt(1); break;
case '2': temp += cipher.charAt(2); break;
case '3': temp += cipher.charAt(3); break;
case '4': temp += cipher.charAt(4); break;
case '5': temp += cipher.charAt(5); break;
case '6': temp += cipher.charAt(6); break;
case '7': temp += cipher.charAt(7); break;
case '8': temp += cipher.charAt(8); break;
case '9': temp += cipher.charAt(9); break;
default: return;
}
}
encrypted = temp;//point temp address to encrypted
return encrypted;
},
decrypt : function (encrypted) {
"use strict";
var i, j, encryptedEx = "", data = "", temp = 0; //index for String substitution
for (j = 0; j < encrypted.length; j += 1) { //substitution
if (encrypted.charAt(j) === cipher.charAt(0)) {
encryptedEx += '0';
} else if (encrypted.charAt(j) === cipher.charAt(1)) {
encryptedEx += '1';
} else if (encrypted.charAt(j) === cipher.charAt(2)) {
encryptedEx += '2';
} else if (encrypted.charAt(j) === cipher.charAt(3)) {
encryptedEx += '3';
} else if (encrypted.charAt(j) === cipher.charAt(4)) {
encryptedEx += '4';
} else if (encrypted.charAt(j) === cipher.charAt(5)) {
encryptedEx += '5';
} else if (encrypted.charAt(j) === cipher.charAt(6)) {
encryptedEx += '6';
} else if (encrypted.charAt(j) === cipher.charAt(7)) {
encryptedEx += '7';
} else if (encrypted.charAt(j) === cipher.charAt(8)) {
encryptedEx += '8';
} else {
encryptedEx += '9';
}
}
encrypted = encryptedEx;
for (i = 0; i < encrypted.length; i = i + 3) {
temp = parseInt(encrypted.charAt(i).toString() + encrypted.charAt(i + 1).toString() + encrypted.charAt(i + 2), 10);
temp -= shift;
data += String.fromCharCode(temp);
}
return data;
}
};
Repository has been moved to github: https://github.com/ferronrsmith/easycrypt
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