Variable-length opaque data is declared in the following way.
opaque identifier<m>;
or
opaque identifier<>;;
The constant m denotes an upper bound of the number of bytes that the sequence can contain. If m is not specified, as in the second declaration, it is assumed to be (2**32) - 1, the maximum length. For example, a filing protocol might state that the maximum data transfer size is 8192 bytes, as follows.
opaque filedata<8192>;