Say I have a file encrypted with GnuPG, in isolation (i.e., I don’t have the relevant keys). Can one then establish the recipients of the encryption? That is:
- Key ID
Or is this information only discernible if you have the appropriate keys?
Likewise, same question for a GnuPG signed file? (i.e., Can you at least establish the signer, without authenticating their signature, without having the key in your keyring?)