Eek!

Eek is a Mac OS X LaunchAgent that will check some URL every time your Mac connects to the Internet and delete important files if it finds certain text in the response. So, if your nice MacBook is stolen or lost, you can create a file at that URL and the first time someone goes on-line with it you can trust that it'll clean out your passwords, bookmarks, SSH keys, &c. Just put this in ~/Library/Application Support/Eek:

#!/bin/sh

echo Eek called at `date` >> ~/Library/Logs/Eek.log

( curl -s -f http://URL | grep 'EEK A MOUSE' ) && \
    echo EEK A MOUSE AT `date` >> ~/Library/Logs/Eek.log && \
    rm -P -r ~/Library/Safari && \
    rm -P ~/Library/StickiesDatabase && \
    rm -P -r ~/.ssh

exit 0

And put this in ~/Library/LaunchAgents/Eek.plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN"
    "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>net.angel.nic.eek</string>
    <key>OnDemand</key>
    <true/>
    <key>ProgramArguments</key>
    <array>
        <string>/Users/yourusername/Library/Application Support/Eek</string>
    </array>
    <key>WatchPaths</key>
    <array>
        <string>/Library/Preferences/SystemConfiguration/com.apple.airport.preferences.plist</string>
    </array>
</dict>
</plist>

Now, if your Mac disappears, you can just put a file at URL containing the words "EEK A MOUSE" and as soon as your Mac connects to a network it'll see that file and clean up your private data. Of course, it's not a bad idea to change the names of these files just in case the person who has your Mac has seen this page!