Please note that except for the mobile phone number, all above addresses are strictly for non-work-related correspondence. Do not send any confidential work-related information to any of the above addresses - please call instead.
For secure email, using GnuPG is preferred.
These keys are strictly for private correspondence. Do not use them for anything work-related. I have separate GnuPG and S/MIME keys for work-related purposes - contact me at my work address to obtain these.
If GnuPG is unavailable to you, you may also try S/MIME, which is the stuff that is available in, say, Mac OS X Mail. However, please note that my capabilities to read S/MIME emails are more limited and may result in a longer time to answer. Download my S/MIME certificate in PEM format or the same certificate in DER format. If this made no sense to you, just try each one.
You will also want to install the CACert root keys in order to properly verify my certificate.
Certificate SHA-1 fingerprint is 33:1f:0b:40:36:03:66:ae:8f:ce:77:ea:a5:98:66:1b:c4:b3:30:c4 (but you shouldn't rely on this - rely on the root).