PBBans should be using SSL encryption (https) by default for the entire site.
Let's Encrypt will be deploying free SSL certificates for the general public. This will not only add encryption security to prevent man-in-the-middle eavesdropping for user's passwords, it will also boost PBBans's SEO credibility and ranking on Google's searches, and possible other search engines, thus increasing the site's exposure and popularity.
https://letsencrypt.org/
The free certificates will be made available to the public sometime this month (November, 2015). Keep an eye open for it.
If you don't want to wait, an alternative solution is StartSSL, which also offers free SSL certificates. The link is http://www.startssl.com/
Cheers,
Knives*