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 against inputfile.txt. 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 command. 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: Filecrypt https://m.majorgeeks.com/files/details/filecrypt.html (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 command): https://www.angelfire.com/pr/pgpf/fcs.html 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. vedaal
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