Detaching signature from signed object

vedaal at vedaal at
Mon Jun 21 18:47:19 CEST 2021

On 6/20/2021 at 2:13 PM, "Matthew Richardson via Gnupg-users" 
wrote:Is there any way in GnuPG to detach (or extract) a signature
from a signed
object?  For example, a signed object is created with:-

>gpg --armor --output signedfile.asc --sign inputfile.txt

where what is wanted is a detached signature which would verify

This feature is in PGP 2:-

>pgp -sa inputfile.txt -o signedfile.asc
>pgp -b signedfile.asc -o verified.txt

which also produces verified.pgp as the detached signature.  The
feature is
described (briefly) in the PGP 2 documentation thus:-

>To detach a signature certificate from a signed message:
>     pgp -b ciphertextfile

Don't know how to do this in GnuPG.

Cannot be done in the PGP  commandlines later than 2.x with the -b
Using the -b command in later PGP commandline versions, just decrypts,
but does not save the signature.

There is a program that can do this for DH keys, using the -b command
but only when encrypted with AES or 3DES:


(n.b  I have NOT used 'this' version, but I did use the original
Filecrypt when it first came out , to successfully use the -b

The developer of Filecrypt is accessible in a link when downloading
the Filecrypt on the majorgeeks site mentioned above.
You might consider discussing a version of Filecrypt with him for your
detached signature use.

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