Public Key

[Dan Norton <dnorton@mindspring.com>]

#1 SMP Debian 3.16.43-2+deb8u2 (2017-06-26)
is on my desktop. In the process of installing borg from:

https://github.com/borgbackup/borg/releases

I have downloaded borg-linux64 and borg-linux64.asc.

From README.txt, there are instructions for verifying the download:

[...]

To check the GPG signature, download both the binary and the corresponding
*.asc file and then (on the shell) type, e.g.:

    gpg --verify borg-linux64.asc borg-linux64

The files are signed by:

Thomas Waldmann <tw@waldmann-edv.de>
GPG key fingerprint: 6D5B EF9A DD20 7580 5747 B70F 9F88 FB52 FAF7 B393
[...]

and after several attempts to add this key and getting:

gpg: no valid OpenPGP data found.

I created borg-linux64.gpg containing the one-liner:

6D5BEF9ADD2075805747B70F9F88FB52FAF7B393

and got past "no valid" by doing (AFAICR):

sudo apt-key add borg-linux64.gpg

If nothing is amiss so far (a big if), the problem now is:

$ gpg --verify borg-linux64.asc borg-linux64
gpg: Signature made Sun 23 Jul 2017 07:23:38 PM EDT using RSA key ID 51F78E01
gpg: Can't check signature: public key not found

How to get the public key?

Thanks,  - Dan