How to validate account address

Address format

The standard format of an account address is NNNN-UUUUUUUU-XXXX:

• NNNN indicates the node id (4 hexadecimal characters).

• UUUUUUUU is the id of the user account (8 hexadecimal characters).

• XXXX is the account address CRC-16/AUG-CCITT checksum (4 hexadecimal characters). If the checksum is not known the string “XXXX” can be used.

Examples:

• 0001-00000000-9B6F

• 0001-00000000-XXXX

• 0015-00000002-3671

• FFFF-FFFFFFFF-A6E1

CRC calculation

JavaScript

function calculateCrc(nodeId, accountId) {
  const d = `${nodeId}${accountId}`;
  let crc = 0x1D0F;
  for (let i = 0, len = d.length; i < len; i += 2) {
    let x = (crc >> 8) ^ parseInt(d.substr(i, 2), 16);
    x ^= x >> 4;
    crc = ((crc << 8) ^ ((x << 12)) ^ ((x << 5)) ^ (x)) & 0xFFFF;
  }
  return crc.toString(16).toUpperCase().padStart(4, '0');
}

PHP

function calculateCrc(string $nodeId, string $accountId): string
{
  $chars = hex2bin($nodeId . $accountId);
  $crc = 0x1D0F;
  for ($i = 0; $i < strlen($chars); $i++) {
    $x = ($crc >> 8) ^ ord($chars[$i]);
    $x ^= $x >> 4;
    $crc = (($crc << 8) ^ ($x << 12) ^ ($x << 5) ^ ($x)) & 0xFFFF;
  }
  return sprintf('%04X', $crc);
}

Validation

JavaScript

function validateAddress(address) {
  const r = /^([0-9A-F]{4})-([0-9A-F]{8})-([0-9A-F]{4}|XXXX)$/;
  const m = r.exec((address || '').toUpperCase());
  if (!m) return false;
  return m[3] === 'XXXX' || m[3] === calculateCrc(m[1], m[2]);
}

PHP

function validateAddress(string $address): bool
{
  $r = '/^([0-9A-F]{4})-([0-9A-F]{8})-([0-9A-F]{4}|XXXX)$/';
  $m = [];
  if (!preg_match($r, strtoupper($address), $m)) {
    return false;
  }
  return $m[3] === 'XXXX' || $m[3] === calculateCrc($m[1], $m[2]);
}