Cryptography: why modes matter, and why 'encrypted' is not always 'unreadable'

You should give proper attribution for your images.<p><a href="http://en.wikipedia.org/wiki/File:Tux.jpg" rel="nofollow">http://en.wikipedia.org/wiki/File:Tux.jpg</a><p><a href="http://en.wikipedia.org/wiki/File:Tux_ecb.jpg" rel="nofollow">http://en.wikipedia.org/wiki/File:Tux_ecb.jpg</a><p><a href="http://en.wikipedia.org/wiki/File:Tux_secure.jpg" rel="nofollow">http://en.wikipedia.org/wiki/File:Tux_secure.jpg</a>

Fair point, attributions modified.