class type scheme =object..end
Generic interface of a padding scheme.
method pad : bytes -> int -> unitpad buf used is called with a byte array buf
containing valid input data at positions 0, ..., used-1.
The pad method must write padding characters in positions
used to Bytes.length str - 1. It is guaranteed that
used < Bytes.length str, so that at least one character of
padding must be added. The padding scheme must be unambiguous
in the following sense: from buf after padding, it must be
possible to determine used unambiguously. (This is what
method Cryptokit.Padding.scheme.strip does.)
method strip : bytes -> intThis is the converse of the pad operation: from a padded
byte array buf as built by method pad, strip buf determines
and returns the starting position of the padding data,
or equivalently the length of valid, non-padded input data
in buf. This method must raise Error Bad_padding if
buf does not have the format of a padded block as produced
by pad.