This page lists usernames of various websites as well as signatures of various cryptographic keys.

If you have reason to believe someone is trying to impersonate me, please contact me right away.

Verify this page: View it in the Google cache or the Wayback machine. The source code is on GitHub. A detached GnuPG signature of this document is available here.

Accounts on websites

Any account on any website that is not listed here (or under deprecated), should be considered an impersonation - please contact me right away!

• Twitter (a.k.a. X): @mathiasertl
• Bluesky: @mathiasertl.bsky.social
• Instagram: matiertl
• GitHub: mathiasertl

Some websites I barely use. Don't expect too much activity here, but feel free to add me to your Network:

• LinkedIn: Mathias Ertl
• Xing: Mathias Ertl

SSH keys

SSH keys used to connect to remote machines. I use unique keys for every host.

• mati@tpx1 (Primary SSH key, since 2023-01-31): id_ed25519.pub, id_rsa.pub

GnuPG

My primary GPG key (download) is used for signing commits on GitHub:

• Fingerprint: E817 2F29 40EA 9F70 9842 2908 70BD 9664 FA39 47CD

This key is renewed every two years.

A second GnuPG key (download): is used on some remote hosts. Since its more likely that the host is compromised, less trust should be given to this (and it is hence only valid for at most a year).

• Fingerprint: 73D8 904C 7230 B6BD ACFB 412D 0B36 C59B D792 B1D9

Deprecated

A short, certainly incomplete list of stuff I don't use anymore:

• SSH keys - remove these keys if you find them on an SSH host:
  • mertl@ubimet.com (SSH key used at Ubimet, from 2021-05-01 until 2023-08-05): id_ed25519.pub, id_rsa.pub
• GitHub: matigit (until 2013-12-22)
• Google+: Mathias Ertl
• Flattr: mathiasertl
• GnuPG: 1D503977 (until 2013-12-01) (download)
• OTR via Jabber/XMPP (just unusable):
  • 17708AFD A10AE972 F8057908 DF5FE9C2 11F3D174
  • D79314F0 37341CAF A4DC7C9D 89838CF1 B9DA55CC
  • 3C753FC6 E881C943 14B6FC20 C0E979B9 2CF9D596
• S/MIME certificates:
  • from 2015-12-25 until 2016-09-18 (download):
    • sha1: E6:31:0A:99:12:E4:69:EE:B0:65:35:92:76:8F:29:A2:D7:62:AE:21
    • sha256: AA:BE:8D:27:84:1E:4F:77:6A:58:F2:68:55:5A:A5:05:91:39:58:4A:9D:BB:B9:06:E4:73:C5:75:92:A3:03:27
  • from 2013-12-25 until 2015-12-25 (download):
    • sha1: 3C:D4:BE:A7:BB:ED:E9:41:26:55:D0:C8:0B:26:74:4C:6E:62:1D:09
    • sha256: 95:85:BD:54:E7:D6:11:EA:A6:86:6A:22:FC:14:AD:0C:06:CA:AD:B7:55:07:08:F2:A4:FD:05:7B:2B:30:C3:14

About this homepage

The source for this homepage is managed on GitHub.