Blackphone CEO Toby Weir-Jones Flickr/Jon Callas The Blackphone is meant to be an ultra-secure smartphone, designed to keep your texts and emails safe from hackers. But Ars Technica reports that there was a big problem with the Blackphone, which meant that its users were actually less secure than people using normal phones.

The Blackphone comes with a range of specialist software designed to help its users communicate more securely. That's where the security flaw came in.

Blackphone's hardware was secure, but one of the apps had a security flaw that hackers could easily use to intercept messages.

SilentText is the instant messaging app that comes with Blackphones. Security researcher Mark Dowd found that the app could be used to find a worrying amount of information about Blackphone users. All hackers needed was a username or phone number. Once they had that, they could read messages, contacts, and even track the location of the phones.

Dowd reported the flaw to Blackphone, and the company has already issued a patch that fixes it. It's not known whether hackers used this flaw to spy on Blackphone users before it was fixed.