One of the most persistent iPhone rumours of recent times is that the next Apple handset will feature a fingerprint scanner.
The rumour started last summer, when Apple bought biometric firm AuthenTec. But since then we've seen mounting evidence that the next iPhone will have the ability to scan your digits.
In the last few days, the packaging for the iPhone 5S has leaked, showing a silver ring around the home button.
This suggests Apple has built in the fingerprint scanner, and wants to draw attention to it on the box.
The standard square on the home button has also vanished, bolstering rumours of a redesign.
Sources speaking to The Wall Street Journal reckon the fingerprint scanner is a dead cert for the iPhone 5S.
One blogger posted pictures of what he claims is the fingerprint scanner, obtained from the Apple supply chain in China.
The feature has even been named. According to leaked documents, the scanner will be called a 'Touch ID sensor'.
Apple will need to put some distance between the iPhone 5S and 5C in order to justify the former's higher price point. Both handsets are expected to run iOS 7, after all.
Even Apple would have a hard time convincing punters to pay extra for a slightly more premium-feeling case and better camera.
A fingerprint sensor would not only make the 5S safer and less vulnerable to being tampered with, it would also show that Apple can still innovate.
Traditionally, a new iPhone features a slight improvement in specs. This is especially true for the 'S' models, which are more modifications than proper new iPhones.
Every year, the tech press bemoans Apple's lack of innovation. And it's justified, to a point.
Apple usually takes existing tech, and puts its own spin on it, making it more user-friendly than anything that's gone before.
OK, fingerprint sensors aren't new - they've featured in laptops for years. But Apple would be the first mainstream tech company to use them in mobiles.
Then of course there's the security aspect.
How many more of us would secure our phones if we could unlock them with just the tap of a finger? No more PIN codes to type in every time you want to use your mobile.
It would also make signing in to websites and social networks far easier. Instead of entering a password, just scan your finger.
Cybercrime is increasingly attractive for criminals. One recent report estimated a staggering 9 million Britons had fallen victim to it in the last year.
We're using our mobiles for more and more nowadays, from banking, to shopping, to social networking, so this type of crime is only going to become more common.
Rivals Samsung and HTC increasingly cram their flagship handsets full of bloatware - i.e. useless software that consumers don't want - and that takes up valuable storage space.
Tech that makes the handset easier to use, faster to unlock, as well as safer would put the iPhone 5S head and shoulders above its rivals.