Reading or extracting the initial file from a signed file

Hi   I'm a Ubuntu user.   I need to read the initial file (the one which has been signed) from a signed pdf file, or extract it under its unsigned form.   The file has been sign with the --sign command, which, I understand, compresses the result. unzip has not been able to decompress it, whic

Signing and symmetrically encrypting files

Hi   I am a little confused with the many gpp's options and need advice.   I want to export files to public servers, keeping them with encryption confidential to any individual outside of a given set of people. These documents have to be accessible to groups of correspondants. I intend to defi