protected function createChecksumVerificationSignature() {
        $privKey = $this->primaryPrivateKey->key();

        $pubKey = $this->primaryPrivateKey->publicKey();
        $address = $pubKey->getAddress()->getAddress();

        $signer = new MessageSigner(Bitcoin::getEcAdapter());
        $signed = $signer->sign($address, $privKey->getPrivateKey());

        return [$address, base64_encode($signed->getCompactSignature()->getBuffer()->getBinary())];
    }