App snap for phone lets you lock it with a look

There's a new smartphone app in town, one that lets users replace their oh-so-tough passwords with a selfie - for like, you know, if you are going senile or something.

Or maybe if you are suddenly too lazy to think, this will be convenient.

According to CNN, the 1U app was part of many that formed part of the 2015 Consumer Electronics Show in Las Vegas.

The app is available in the Apple App Store or on Google Play for free.

Those who have downloaded it via Google Play have rated it an average of 3.8 stars out of five.

After a tedious registration process that requires confirmation that you are older than 12, and provision of your e-mail address, among other details, you are ready to go.

Hector Hoyos, the president of developer Hoyos Labs, told CNN that there was a slim chance of being hacked.

"We developed technology which is Lifeness, which actually detects that you're a live person.

"And we do that by various methods. One is looking at pupil dilation, asking a user to facial sensing, which means you can raise your eyebrows, smile, do different things that detect motion of the muscles.

"Everything is possible to be hacked, but the probability is very, very low."

Facebook has been using facial recognition technology to help suggest tags on photos uploaded by users, while Google+ also uses similar software.

Of course there have been other similar apps - FotoTiger for Facebook, which is free, stores your Facebook friends list. If you do not want to upload new pictures of your friends to Facebook, the tags are kept locally to organise the photos based on the people in them.