I send mail signed with my PGP key. The fingerprint is 94B3 3D04 F47E 6611 ADD9 76A6 76F8 F1CB 49F9 1B02. You can download the key like so:
# FreeBSD:
$ fetch -o - https://www.53hor.net/contact/atc.gpg | gpg --import
# Also FreeBSD, but more inclusive:
$ curl https://www.53hor.net/contact/atc.gpg | gpg --import