Hello,

I will organize a PGP keysigning event for the participants of Linux
Plumbers and Open Source Summit Europe in Prague this October.

The idea is to meet during the two conferences and exchange/verify PGP
fingerprints and (depending on how you practise keysigning) ID checking. 
Then each participant back at home can sign the verified certificates to
improve the web of trust. (Current state of the web of trust (as of
commit f8c2189fb65f in the kernel's pgpkeys repo):

 - 654 certificates, among them 12 invalid
 - 8088 signatures, 3613 of them invalid
 - 9 certificates are not reachable from Greg's stable key
   (38DBBDC86092693E).
 - 317 certificates are not reachable from Linus's cert
   (79BE3E4300411886). (That's why Greg is used as trust root since some
   time.)
 - strong set size: 289
 - average distance in the strong set: 4.85
 - maximal distance in the strong set: 13
 - Best connected certificate is Daniel Wagner's 587C5ECA5D0A306C which
   can reach the other strong set certs with an average of 3.89 steps.
)

The gatherings will be on Tue 2026-10-06 and Thu 2026-10-08 (that is on
the second day of each conference) after the official program.

I don't know the conference location and also don't have any idea yet
how many people will participate, so I will communicate the location and
exact time later. (If you have insights about the possibilities there,
please reach out.)

While it's not mandatory, please register by sending your PGP
certificate ("public key") to lpcosse-keysigning@baylibre.com until
2026-09-27 08:00 UTC. Your certificate doesn't need to be in the kernel
pgpkeys repo for that. I will prepare a text file with all the
registered certificates to speed up the event using the
Zimmermann–Sassaman key-signing protocol[1]. You can join without
sending your certificate, but then you have to care yourself about how
to share your fingerprint. (Probably use gpg-key2ps to prepare paper
slips with your certificate data. Having some of these even if you're on
the list might be a good idea.)

Note I will provide the text file (and thus all the personal information
contained in the certificates I receive) in this mail thread to allow
late joining (without being on the list then though). If you don't agree
to that, don't send in your certificate.

If you have questions, don't hesitate to ask (using above email
address).

Best regards
Uwe

[1] https://en.wikipedia.org/wiki/Zimmermann%E2%80%93Sassaman_key-signing_protocol