E-Mail

Remember that e-mails are similarly insecure as postcards and people snoop on them. If you know how to do it, use my public PGP key. (Instructions in English and German)

guenther at unix dash ag dot uni dash kl dot de

PGP fingerprint:
7F02 BDCC 6157 6E11 1A87
9BD1 1C62 9E5A F9E8 CDA1

Other

I have a Swiss and a German cell phone number, and am using TextSecure and Threema on my phone, registered with the Swiss phone number. I do not use Facebook.

Or you can just leave a public comment below.