neizod/LICENSE.txt

## README.md

      
    Raw
  

              README.md
            
          
    The Affine Cipher

139b. Encrypt and decrypt text using affine cipher method.
How to Use

Invoke function using 4 arguments.
1st arg (string) ... Input pain/cipher text. Its can contain only English alphabet [a..z], no punctuation.
2nd arg (number) ... The multiplication number. Only [1, 3, 5, 7, 9, 11, 15, 17, 19, 21, 23, 25] are valid.
3rd arg (number) ... The key number. Range [0..25].
4th arg (number) ... Direction of encrypt/decrypt. 1 for encryption and 0 for decryption.

Let's Talk

By studying @wrayal's Vigenère Cipher. I decide to implement the popular well-known Caesar cipher again.
But then I realized that Caesar cipher is just one special case from Vigenère cipher. That's mean I done nothing new! So I rewrite this function in Affine cipher. Which still can be use as the Caesar cipher by setting the 2nd arg = 1, e.g. function("texthere", 1, 4, 1).

  
## annotated.js
function(
    t,      // input text string.
    m,      // input multiplication number.
    k,      // input key number.
    d,      // direction.
            // placeholder.
    a       // current alphabet
){
    for(var x=i=o="";                   // init counter -> i, outtext -> o, and inverse multiplier -> x.
        a=t.charCodeAt(i++)+7;          // grap char at i, parse it to number.  and loop through text.
        o+=String.fromCharCode((        // parse char from number after finished this below steps.
                (d?m:x)*a+                  // multiple a with the right multiplier.
                (d?1:-x)*k)                 // multiple k with the right multiplier. then add to a.
                %26+97))                    // parse base-26 number back to ascii code. (finished)
                    while(m*++x%26-1);  // find inverse multiplier and store them as x.
    return o
}

## index.js
function(t,m,k,d,a){for(var x=i=o="";a=t.charCodeAt(i++)+7;o+=String.fromCharCode(((d?m:x)*a+(d?1:-x)*k)%26+97))while(m*++x%26-1);return o}

## LICENSE.txt
            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2011 Nattawut Phetmak <http://about.me/neizod>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.

## package.json
{
  "name": "affineCipher",

  "description": "this will encrypt/decrypt your text using the affine method.",

  "keywords": [
    "affine",
    "cipher",
    "encryption",
    "decryption",
    "string"
  ]
}

## test.html
<!DOCTYPE html>
<title>The Affine Cipher</title>
<div>Expected value: <b>insxchmrwbglqvafkpuzejotyd, exxegoexsrgi, iminlovewithmybestfriend</b></div>
<div>Actual value: <b id="ret"></b></div>
<script>
  // write a small example that shows off the API for your example
  // and tests it in one fell swoop.

  var affine = function(t,m,k,d,a){for(var x=i=o="";a=t.charCodeAt(i++)+7;o+=String.fromCharCode(((d?m:x)*a+(d?1:-x)*k)%26+97))while(m*++x%26-1);return o}

  document.getElementById( "ret" ).innerHTML = [affine("abcdefghijklmnopqrstuvwxyz", 5, 8, 1),
                                                affine("attackatonce", 1, 4, 1),
                                                affine("lnlugbyjflkentojdkqwljuc", 7, 7, 0)];
</script>
	function(
	t, // input text string.
	m, // input multiplication number.
	k, // input key number.
	d, // direction.
	// placeholder.
	a // current alphabet
	){
	for(var x=i=o=""; // init counter -> i, outtext -> o, and inverse multiplier -> x.
	a=t.charCodeAt(i++)+7; // grap char at i, parse it to number. and loop through text.
	o+=String.fromCharCode(( // parse char from number after finished this below steps.
	(d?m:x)*a+ // multiple a with the right multiplier.
	(d?1:-x)*k) // multiple k with the right multiplier. then add to a.
	%26+97)) // parse base-26 number back to ascii code. (finished)
	while(m*++x%26-1); // find inverse multiplier and store them as x.
	return o
	}
	DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
	Version 2, December 2004

	Copyright (C) 2011 Nattawut Phetmak <http://about.me/neizod>

	Everyone is permitted to copy and distribute verbatim or modified
	copies of this license document, and changing it is allowed as long
	as the name is changed.

	DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
	TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

	0. You just DO WHAT THE FUCK YOU WANT TO.
	{
	"name": "affineCipher",

	"description": "this will encrypt/decrypt your text using the affine method.",

	"keywords": [
	"affine",
	"cipher",
	"encryption",
	"decryption",
	"string"
	]
	}
	<!DOCTYPE html>
	<title>The Affine Cipher</title>
	<div>Expected value: <b>insxchmrwbglqvafkpuzejotyd, exxegoexsrgi, iminlovewithmybestfriend</b></div>
	<div>Actual value: <b id="ret"></b></div>
	<script>
	// write a small example that shows off the API for your example
	// and tests it in one fell swoop.

	var affine = function(t,m,k,d,a){for(var x=i=o="";a=t.charCodeAt(i++)+7;o+=String.fromCharCode(((d?m:x)a+(d?1:-x)k)%26+97))while(m*++x%26-1);return o}

	document.getElementById( "ret" ).innerHTML = [affine("abcdefghijklmnopqrstuvwxyz", 5, 8, 1),
	affine("attackatonce", 1, 4, 1),
	affine("lnlugbyjflkentojdkqwljuc", 7, 7, 0)];
	</script>