Untitled

<?php

// Function for check address
function checkAddress($address) {

	$origbase58 = $address;
	$dec = "0";

	for ($i = 0; $i < strlen($address); $i++) {
		$dec = bcadd(bcmul($dec,"58",0),strpos("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz",substr($address,$i,1)),0);
	}

	$address = "";

	while (bccomp($dec,0) == 1) {
		$dv = bcdiv($dec,"16",0);
		$rem = (integer)bcmod($dec,"16");
		$dec = $dv;
		$address = $address.substr("0123456789ABCDEF",$rem,1);
	}

	$address = strrev($address);

	for ($i = 0; $i < strlen($origbase58) && substr($origbase58,$i,1) == "1"; $i++) {
		$address = "00".$address;
	}

	if (strlen($address)%2 != 0) {
		$address = "0".$address;
	}

	if (strlen($address) != 50) {
		return false;
	}

	if (hexdec(substr($address,0,2)) > 0) {
		return false;
	}

	return substr(strtoupper(hash("sha256",hash("sha256",pack("H*",substr($address,0,strlen($address)-8)),true))),0,8) == substr($address,strlen($address)-8);
}

include_once 'db.php';
?>
<!DOCTYPE html>
<html>
	<head>
		<title>Save address</title>
	</head>
	<body>
		<?php

			// Check if form submitted
			if($_SERVER['REQUEST_METHOD'] == 'POST') {

				// Check if address valid and insert into db if so
				if(checkAddress($_POST['address'])){

					// Save address
					$request = $conn->prepare('INSERT INTO address VALUES (:address)');
					$request->execute([
					'address' => $_POST['address']
					]);

					// Show success
					?>
						<b>Address registered successfully ( You can use HTML here ).</b>
					<?php
				} else {

					// Display error if address not valid
					?>
						<b>Can't verify address ( You can use HTML here ).</b>
					<?php
				}
			} else {

				// Display form if form not submitted
				?>
					<form method="POST">
						<input type="text" placeholder="Address" name="address" id="address" />
						<button type="submit">Submit</button>
					</form>
				<?php
			}
		?>
	</body>
</html>