PHP CLASS I USED TO VALIDATE AN BITCOIN ADDRESS
namespace Bitcoin;
class AddressValidator {
CONST MAINNET = "00";
CONST TESTNET = "6F";
static public function isValid($addr, $version = null) {
if (is_null($version)) {
$version = self::MAINNET;
}
if (preg_match('/[^1-9A-HJ-NP-Za-km-z]/', $addr)) {
return false;
}
$decoded = self::decodeAddress($addr);
if (strlen($decoded) != 50) {
return false;
}
if (substr($decoded, 0, 2) != $version && substr($decoded, 0, 2) != "05") {
return false;
}
$check = substr($decoded, 0, strlen($decoded) - 8);
$check = pack("H*", $check);
$check = hash("sha256", $check, true);
$check = hash("sha256", $check);
$check = strtoupper($check);
$check = substr($check, 0, 8);
return ($check == substr($decoded, strlen($decoded) - 8));
}
static protected function decodeAddress($data) {
$charsetHex = '0123456789ABCDEF';
$charsetB58 = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz';
$raw = "0";
for ($i = 0; $i < strlen($data); $i++) {
$current = (string) strpos($charsetB58, $data[$i]);
$raw = (string) bcmul($raw, "58", 0);
$raw = (string) bcadd($raw, $current, 0);
}
$hex = "";
while (bccomp($raw, 0) == 1) {
$dv = (string) bcdiv($raw, "16", 0);
$rem = (integer) bcmod($raw, "16");
$raw = $dv;
$hex = $hex . $charsetHex[$rem];
}
$withPadding = strrev($hex);
for ($i = 0; $i < strlen($data) && $data[$i] == "1"; $i++) {
$withPadding = "00" . $withPadding;
}
if (strlen($withPadding) % 2 != 0) {
$withPadding = "0" . $withPadding;
}
return $withPadding;
}
}
