length, of course.) Transformations may be key-dependent, in which
case key material is passed in at initialisation time. They may
also depend on internal factors (eg. time) and keep internal
state. A struct transform_if only represents a particular type of
transformation; instances of the transformation (eg. with
length, of course.) Transformations may be key-dependent, in which
case key material is passed in at initialisation time. They may
also depend on internal factors (eg. time) and keep internal
state. A struct transform_if only represents a particular type of
transformation; instances of the transformation (eg. with