I think "l=" and "x=" both put more information into the hands of the
verifiers.
Well, sure, but the question is whether that information is useful. We
could include the phase of the moon and the software author's middle name,
too.
Both l= and x= are bad for interoperability, because it is utterly unclear
what a recipient will do with them. Whevever I ask, the answer is they
might do this and they could do that. If I put a really long x= into a
signature, will recipient systems accept a stale message that otherwise
they wouldn't? If I sign the first 100 bytes of a 10K message, will
recipient systems accept it, and if so, what will users see? There's no
way to tell, because everyone just makes something up.
I'm all in favor of standards communicating useful information, but if you
don't have an agreed algorithm for what to do with it, you're just going
to get more confusion, not better results.
R's,
John
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