@Override
    protected byte[] engineGetEncoded(String format) throws IOException {
        if (format == null || format.equals("ASN.1")) {
            return engineGetEncoded();
        } else if (format.equals("RAW")) {
            return iv.clone();
        } else {
            throw new IOException("Unsupported format: " + format);
        }
    }
An implementation of {@link java.security.AlgorithmParameters} that contains only an IV.  The
supported encoding formats are ASN.1 (primary) and RAW.
common/src/main/java/org/conscrypt/IvParameters.java