private var keyAlgorithm: String? = null
    private var keySize: Int = 0

    init {
      ecdsa256()
    }

    /**
     * Sets the certificate to be valid in ```[notBefore..notAfter]```. Both endpoints are specified
     * in the format of [System.currentTimeMillis]. Specify -1L for both values to use the default
     * interval, 24 hours starting when the certificate is created.
     */
    fun validityInterval(