// MECH_OID
        if ( buf.length < i + len ) {
            throw new IllegalArgumentException();
        }
        byte[] bo = new byte[len];
        System.arraycopy(buf, i, bo, 0, len);
        i += len;
        this.oid = ASN1ObjectIdentifier.getInstance(bo);

        // NAME_LEN
        if ( buf.length < i + NAME_LEN_SIZE ) {
            throw new IllegalArgumentException();
        }