<?php

$str = encode_str("19876");

echo '<br/>'.$str.'<br/>' ;

echo decode_str($str);

/**

* 1. Get ASCII of each char add an random salt and again add with an random multple (1x to 9x) of 1000 to keep each unit 4 char length.

* 2. Convert 0, 1, 2, 3, 4, 5 in obtained string to alphabet

* @param string $str

* @return type

*

*/

function encode_str($str) {

$encoded = '';

$alpha_map = ['P', 'M', 'S', 'K'];

$str = ''.$str;

$len = strlen($str);

$ascii_arr = [];

$salt = 150;//rand(100, (999 - 255));

for ($x = 0; $x < $len; $x++) {

$ascii_arr[$x] = (rand(1, 9) * 1000) + ($salt + ord($str[$x]));

}

$enc = implode('', $ascii_arr) . $salt;

$enc_len = strlen($enc);

for ($x = 0; $x < $enc_len; $x++) {

if (array_key_exists($enc[$x], $alpha_map)) {

$encoded .= $alpha_map[$enc[$x]];

} else {

$encoded .= $enc[$x];

}

}

return strtolower($encoded);

}

function decode_str($str) {

$str = strtoupper($str);

$unit_size = 4;

$alphatonum = function($s) {

$alpha_map = ['P', 'M', 'S', 'K'];

$l = strlen($s);

$s_ = '';

for ($x = 0; $x < $l; $x++) {

$pos = array_search($s[$x], $alpha_map);

$s_ .= in_array($s[$x], $alpha_map) ? array_search($s[$x], $alpha_map) : $s[$x];

}

return $s_;

};

$decoded = '';

$salt = $alphatonum(substr($str, -3));

$data = $alphatonum(substr($str, 0, strlen($str) - 3));

$loop = strlen($data) / $unit_size;

$unit_arr = [];

for ($x = 0; $x < $loop; $x++) {

$unit = substr($data, $x * $unit_size, $unit_size);

$ascii_ = ($unit % 1000) - $salt;

$decoded .= chr($ascii_);

}

return $decoded;

}

?>

<script type="text/javascript">

var encod = encode_str('19');

console.log(encod)

console.log(decode_str(encod))

function encode_str(str) {

var encoded = '';

var alpha_map = ['P', 'M', 'S', 'K'];

var str = str.toString();

var len = str.length;

var ascii_arr = [];

var salt = 150;//rand(100, (999 - 255));

for (var x = 0; x < len; x++) {

ascii_arr[x] = (rand(1, 9) * 1000) + (salt + str.charCodeAt(x));

}

var enc = ascii_arr.join('') + salt;

var enc_len = enc.length;

for (var x = 0; x < enc_len; x++) {

if (typeof(alpha_map[enc[x]]) != 'undefined') {

encoded += alpha_map[enc[x]];

} else {

encoded += enc[x];

}

}

return encoded.toLowerCase();

}

function decode_str(str) {

str = str.toUpperCase();

var unit_size = 4;

var alphatonum = function(s) {

var alpha_map = ['P', 'M', 'S', 'K'];

var l = s.length;

var s_ = '';

for (var x = 0; x < l; x++) {

var pos = alpha_map.indexOf(s[x]);

s_ += (pos >= 0) ? pos : s[x];

}

return s_;

};

var decoded = '';

var salt = alphatonum(str.substr(-3));

var data = alphatonum(str.substr(0, (str.length - 3)));

var loop = data.length / unit_size;

for (var x = 0; x < loop; x++) {

var unit = data.substr(x * unit_size, unit_size);

var ascii_ = (unit % 1000) - salt;

decoded += String.fromCharCode(ascii_)

}

return decoded;

}

function rand(x, y) {

return parseInt(Math.random() * (y + 1 - x) + x, 10);

}

</script>