fun checkSignature(issuer: PublicKey): Boolean {
    val signedData = CertificateAdapters.tbsCertificate.toDer(tbsCertificate)

    return Signature.getInstance(tbsCertificate.signatureAlgorithmName).run {
      initVerify(issuer)
      update(signedData.toByteArray())
      verify(signatureValue.byteString.toByteArray())
    }
  }

  fun toX509Certificate(): X509Certificate {
    val data = CertificateAdapters.certificate.toDer(this)