BIP32 serialization version byte swap using BitWasp's bitcoin-php library

swap-version.php

<?php

use BitWasp\Bitcoin\Base58;
use BitWasp\Buffertools\Buffer;
use BitWasp\Buffertools\BufferInterface;
use BitWasp\Buffertools\Buffertools;

require "./vendor/autoload.php";

class XKeyUtil {
  private static $VERSION_PREFIXES = [
    'drkv' => '02fe52f8',
    'drkp' => '02fe52cc',
    'DRKV' => '3a8061a0',
    'DRKP' => '3a805837',
    'xpub' => '0488b21e',
    'xprv' => '0488ade4',
    'tpub' => '043587cf',
    'tprv' => '04358394',
  ];

  static public function swap_prefix($xkey, $prefix) {
    $hex;
    try {
      $hex = Base58::decodeCheck($xkey)->getHex();
    }
    catch (\Exception $e) {
      $hex = 'Invalid base58 data';
    }

    $nh = self::$VERSION_PREFIXES[$prefix] . substr($hex, 8, 156);
    $new_xkey = Base58::encodeCheck(Buffer::hex($nh));

    return $new_xkey;
  }
}

// Convert this 'tpub' xkey (Bitcoin testnet extended public key) into a
// Dash testnet public key (should be DRKV...)
//
$xpub = 'tpubD6NzVbkrYhZ4XaR63SeDvZ4M8FVvK7Lm1YKn88N1Zbv8JQhKJdESyXpNJX6uSmZKeDKsVCXyJ57rsUi7VtPbdEMApmBuJidFAuFg7xRohCZ';

$hex;
try {
  $hex = Base58::decodeCheck($xpub)->getHex();
}
catch (\Exception $e) {
  $hex = 'Invalid base58 data';
}

$nk = XKeyUtil::swap_prefix($xpub, 'DRKV');
echo $nk . PHP_EOL;

// Result should be:
//
// DRKVrRjogj3bNiLD8U7tZnDNvmKhJD4Jb6CKF61rFBo5rCg5JnWFaySgX4u6q7brLyEMPr6TSnNSRwg42HBSgEwjR4Lss9cbuThGz3qEqdKmfSKf