phpOMS/Validation/BitcoinValidator.php

<?php
/**
 * Orange Management
 *
 * PHP Version 7.0
 *
 * @category   TBD
 * @package    TBD
 * @author     OMS Development Team <dev@oms.com>
 * @author     Dennis Eichhorn <d.eichhorn@oms.com>
 * @copyright  2013 Dennis Eichhorn
 * @license    OMS License 1.0
 * @version    1.0.0
 * @link       http://orange-management.com
 */
namespace phpOMS\Validation;

class BitcoinValidator 
{
    public static function validate(string $addr)  : bool
    {
        $decoded = self::decodeBase58($addr);
 
        $d1 = hash("sha256", substr($decoded, 0, 21), true);
        $d2 = hash("sha256", $d1, true);
 
        if (substr_compare($decoded, $d2, 21, 4)) {
            return false;
        }

        return true;
    }

    public static function decodeBase58(string $input) : string
    {
        $alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
 
        $out = array_fill(0, 25, 0);
        $len = strlen($input);

        for ($i = 0; $i < $len; $i++) {
                if (($p = strpos($alphabet, $input[$i])) === false) {
                        throw new \Exception("invalid character found");
                }

                $c = $p;
                for ($j = 25; $j--;) {
                        $c += (int) (58 * $out[$j]);
                        $out[$j] = (int) ($c % 256);
                        $c /= 256;
                        $c = (int) $c;
                }

                if ($c !== 0) {
                    throw new \Exception("address too long");
                }
        }
 
        $result = "";
        foreach ($out as $val) {
                $result .= chr($val);
        }
 
        return $result;
    }
}