@Override
    protected void engineInit(AlgorithmParameterSpec algorithmParameterSpec)
            throws InvalidParameterSpecException {
        if (!(algorithmParameterSpec instanceof IvParameterSpec)) {
            throw new InvalidParameterSpecException("Only IvParameterSpec is supported");
        }
        iv = ((IvParameterSpec) algorithmParameterSpec).getIV().clone();
    }
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