Twitter experienced downtime and elevated error rates for less than an hour today following the rollout of a setting that beefs up security by default.

Even with the timing of the opt-in HTTPS feature, neither the cause of the problem, nor how widespread it was, has yet been revealed by the company. A note on Twitter's status blog simply notes that the company is aware of the problem and taking steps to fix it.

The Hyptertext Transfer Protocol Secure (HTTPS) mode, encrypts the username, password, and any personal data, keeping it from being useful if intercepted by thieves. It comes standard on the mobile iPhone version of Twitter, though not on m.Twitter.com just yet. The new option, found in Twitter's general settings enables users to force the service to always use HTTPS.

Update at 3:25 p.m.: Twitter says the problem has been fully sorted out. "This issue is resolved, access to all features for all users is restored," the company said on its status blog.