ONC+ Developer's Guide

Description

The standard also provides for variable-length (counted) opaque data, defined as a sequence of n (numbered 0 through n-1) arbitrary bytes to be the number n encoded as an unsigned integer (as described subsequently), and followed by the n bytes of the sequence.

Byte b of the sequence always precedes byte b+1 of the sequence, and byte 0 of the sequence always follows the sequence's length (count). The n bytes are followed by enough (0 to 3) residual zero bytes, r, to make the total byte count a multiple of four.