@Override
  public boolean equalsKey(Key o) {
    if (!(o instanceof HpkePrivateKey)) {
      return false;
    }
    HpkePrivateKey other = (HpkePrivateKey) o;
    return publicKey.equalsKey(other.publicKey)
        && privateKeyBytes.equalsSecretBytes(other.privateKeyBytes);
  }
Creates a new HPKE private key.

@param publicKey Corresponding HPKE public key for this private key
@param privateKeyBytes Private key encoded according to
    https://www.rfc-editor.org/rfc/rfc9180.html#section-7.1.2
java_src/src/main/java/com/google/crypto/tink/hybrid/HpkePrivateKey.java