Glam,

Glam wrote:
> 
> is it possible (according to the PDF standard, and in iText) to have two
> signatures for the same revision? 

just one afterthought... if you seriously want to be in the signature
business, you should not only keep in mind the current plain PDF standard
(i.e. ISO-32000-1:2008) but also additional standards.

E.g., confer ETSI TS 102 778-1; section 4.1 in v1.1.1 says: "As with other
CMS-based signature implementations, a digest is computed over a range of
bytes of the file. However with PDF, as the signature information is to be
embedded into the document itself, this range is the entire file, including
the signature dictionary but excluding the PDF Signature itself. The range
is then indicated by the ByteRange entry of the signature dictionary. 

By restricting the ByteRange entry this way, it ensures that there are no
bytes in the PDF that are not covered by the digest, other than the PDF
signature itself.

NOTE: The profiles defined in part 2 and 3 make normative this requirement
which is a recommendation in ISO 32000-1 [1], clause 12.8.1." 

Therefore, as soon as you're into signatures seriously, the signed byte
range simply has to cover all of the revision but the one signature
container which signs this very byte range. 

Regards,   Michael.
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