Multiple signatures

David Shaw dshaw at
Mon Oct 3 23:59:59 CEST 2011

On Oct 3, 2011, at 1:49 PM, pet jemen wrote:

> Hi,
> I want to sign binary data in OpenPGP Message Format.
> I want sign it by two or more keys.
> According to it seems it is possible.
>  (A one-octet number holding a flag showing whether the signature is nested.  A zero value indicates that the next packet is another One-Pass Signature packet that describes another signature to be applied to the same message data.)
> I'd like to use gpg from command-line to sign an input file by two keys.
> I tried to sign it by:
>    gpg2.exe --quiet --yes --force-v3-sigs -z 0 -u "test1 (test1) <test1 at>" -o %1.signed --sign %1
>    gpg2.exe --quiet --yes --force-v3-sigs -z 0 -u "test2 (test2) <test2 at>" -o %1.signed2 --sign %1.signed
> But the second signature signed the first one also with the first signature.
> I need to sign it in way were I can verify signature of signed data by both keys (the last octet of One-Pass Signature Packets (Tag 4) packet should be equal to zero).

Just repeat -u as many times as you need:

  gpg -u the-first-key -u the-second-key -u the-third-key -u etc --sign thefile


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