On Thu, Jan 14, 2021 at 8:16 PM Stefan Claas <spam.trap.mailing.li...@gmail.com> wrote: > > On Thu, Jan 14, 2021 at 10:46 AM Ayoub Misherghi via Gnupg-users > <gnupg-users@gnupg.org> wrote: > > > > > > I am encrypting and signing documents with myself as the receiver. Nobody > > else will want to look inside them. Is it possible to add encrypted > > comments or other information to a separated signature file; and later > > retrieve this additional information? I want to be able to decrypt the > > signature file alone and retrieve all the information I put inside it. > > You can add Comments: to a detached signature, yes, but beware that these > encrypted content must be seperated for each comment line. > > I have not tested this yet, but you could with a shell script use some format > or lenght preserving encryption software, like Google's Adiantum with a base64 > encoder and then would have the smallest possible symmetrically encrypted > output for a message as Comment: line. You can do this also manually > of course as much as you wish because it does not invalidate the signature. > > Hope this helps a bit.
Here is a quick manually inline sig. First message with GnuPG symmetric content in Comment lines and second same message with Google's Adiantum+base64 You see the difference, what I mean with format preserving. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Hello World! :-) Regards Stefan -----BEGIN PGP SIGNATURE----- Comment: -----BEGIN PGP MESSAGE----- Comment: Comment: jA0EBwMCMx3mMIiLwjPH0mgBh3We4k31HkKJ7W8c9oju++X96uaNVB5mMEDJhhr6 Comment: Ao5wibzeivfsfFL9Si2cCc/X9kUG2maKHSwb+51nwtcFSRNT2h99SQlbMPzRkoku Comment: EkyCpYpeq+d8gyMeJ+uNgEvtAwHF35RYVQ== Comment: =Vain Comment: -----END PGP MESSAGE----- iHUEARYIAB0WIQR61Pk5PUF7u6Rs+mem3tVibXmEGgUCYACeDgAKCRCm3tVibXmE Gpk6AP98iXZb8gd0NDvOllByTHkrcQvQluXd/db1c5u+skm90gEAj5c991XdP5s5 clB9wwK9G8XoCDJnhfMLWljuvjCM8Ac= =XJXL -----END PGP SIGNATURE----- -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Hello World! :-) Regards Stefan -----BEGIN PGP SIGNATURE----- Comment: vHgPAUzXglLiVFelwf0jjUzXCNIqSrinvNhjF+JRkd8K iHUEARYIAB0WIQR61Pk5PUF7u6Rs+mem3tVibXmEGgUCYACeDgAKCRCm3tVibXmE Gpk6AP98iXZb8gd0NDvOllByTHkrcQvQluXd/db1c5u+skm90gEAj5c991XdP5s5 clB9wwK9G8XoCDJnhfMLWljuvjCM8Ac= =XJXL -----END PGP SIGNATURE----- Regards Stefan _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
