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gnupg

Gpg message metadata

I want to send message, encrypted with GPG utility, likt that:

-----BEGIN PGP MESSAGE-----
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=4SsM

-----END PGP MESSAGE-----

but i won't everybody know sender or receiver of it's message. That's why i have a question - can i retrieve information about sender or recipient of this message?

Solution

  • can i retrieve information about sender or recipient of this message?

    Yes. You can retrieve the key identifiers of the recipients of the message.

    Your PGP block contains the identifiers of the RSA public keys that have encrypted it: 83836B8F.

    gpg -d < /tmp/your_pgp_file
gpg: encrypted with RSA key, ID 83836B8F
gpg: decryption failed: secret key not available

    Usually we encrypt data with the public key of the sender, and the public keys of the recipients. In this example we do not know who is 83836B8F, but in your context you probably know.