cv25519 scalar byte order

Werner Koch wk at
Mon Apr 9 18:53:53 CEST 2018

On Mon, 19 Feb 2018 17:24, dkg at said:

>> That would be incorrect.  The prefix (e.g. 0x40) indicates a _point_
>> format and not the format of a scalar.  Thus skey[3] MAY not have this
>> prefix.
> what does this "MAY NOT" mean?  if this is an attempt at RFC 2119
> language, i don't understand it.  Do you mean "MUST NOT" ?

I was thinking SHOULD NOT but indeed it MUST be MUST NOT.

> What steps are needed to clarify the documentation here so that we can
> have interoperable implementations?

I can't remember an open issue regaring this in the WG.  Should be
handled there anyway,



#  Please read:  Daniel Ellsberg - The Doomsday Machine  #
Die Gedanken sind frei.  Ausnahmen regelt ein Bundesgesetz.
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