Keysigning on Chemnitz Linux-Days

Date of key signing

The key signing party will once again take place during the Chemnitzer Linux-Tage 2019. We will meet on Saturday, 16th March at 5.00 p.m. in room W3. We will compare the fingerprints of our PGP keys and thus extend our web of trust.

What is keysigning?

Encryption of data or proving their correctness is necessary for various confidential issues. One solution of this problem is offered by GnuPG. By using GnuPG, you can create a pair of keys associated with name and email address in order to protect or digital sign your data.

In case another person would like to sent you confidential information he has the opportunity to search for your public key and use it in order to encrypt his email.

However how can this person ensure that the denounced key really is the appropriate one? Finally everybody is able to create a key by using any name. In order to obtain more security, so called key signing parties are held. This means that people will meet and compare their identity cards in order to ensure that the person related to the key and the person met in reality are the same. When this is clear they sign each others key.

Users of GnuPG are able to show a list of all subscribers by typing the command gpg --list-sigs KEYID
(where KEYID stands for a distinct key name). In general, it can be assumed that a key is more trustworthy the more signings it has.

We would like to meet at the Chemnitzer Linux Tag in order to verify the data of every participating key. The advantage of key signing at central events is the efficiency due to a congregation of many owners at a particular place. That strengthens everybody's web of trust.


What do you have to do in order to take part in the key signing?

  • Create a pair of keys, if not already done
    • In case of using GnuPG type gpg --gen-key for generating. For further information read the HOWTO.
    • If you already own a key, it should be registered on a public key server.
  • Before keysigning, download the list of subscribers and verify that your key is included. If your key is not listed within two or three days, please get again in touch with the above-named address. The final list will be provided a few days before the Chemnitzer Linux Tage - All members of list will receive information via email.
  • Calculate the MD5, SHA1, and SHA256 hash sum of the list. This can be done by using the programs md5sum, sha1sum, or sha256sum from GNU Coreutils. Also GnuPG (gpg --print-mds $FILE) or another program can perform this task. The calculated value has to be entered into the appropriate field of the list and will be compared on day of keysigning.
  • Print out the list and bring it along with you when visiting the Chemnitzer Linux Tage.

Procedure of key signing

As already mentioned, the identity of every key owner has to be verified by means of an official document. Most appropriate are the identity card or passport. It should be valid on day of key signing.

However, on meeting we will start compare the calculated checksum for the list to ensure, everybody is using the last and correct version of the attendees list. If this was successful, we will verify the identities one after another by building up a row and moving around. So everybody have the chance to check each attendees identity.

After this has been done, you can sign all keys you trust in at the computer. Using GnuPG you have to type gpg --sign-key KEYID or gpg --edit-key KEYID in order to do that.

Indeed, it is better to automatise the signing. The small programme signing-party/caff is suited best for this job.

Further information

For further questions, please do not hesitate to get in touch with me.

My contact data are:

Jens Kubieziel
60D8 5B8D 9A1C D2D1 355E BE9F 65B3 F094 EA3E 4D61

For additional information you can also read the GPG key signing party HOWTO