I support encrypted communication and encourage everyone to do that as well.
GPG
I prefer GPG. My current GPG key:
pub rsa4096 2017-04-09 [SC] [expires: 2023-04-08]
97B1 20E7 6B79 ACB7 D211 2875 16F6 1D41 1E4E E897
Old GPG Keys
The following keys can still be used, but I recommend to replace them as soon as possible.
806E B64E 91F2 4718 9160 C233 9549 DD04 E2EF 5D13
expires 2018-11-19
OTR
For my XMPP:
63728113 1D7FC937 9218CF32 05CB28F1 866C8F98
S/MIME
I used to support S/MIME, but it is difficult to find trustworthy CAs who issue S/MIME certificates at reasonable rates. Thus, I will no longer offer S/MIME.