This Free App Can Solve the Space Crunch on Your Phone; but It Wants Your Trust

By now, you might have heard of WhatsApp Magic Cleaner, a free app that claims that it can remove all the junk images and spammed jokes that have been recirculated on the many WhatsApp groups you're probably a part of. Even if you're not someone who avidly forwards the latest joke on WhatsApp, it's pretty much a certainty today that you know people who do, and that means that you're at the receiving end of dozens of funny images and memes. Or maybe you like sending jokes forward as well, without thinking about the fact that people are running out of space on their phones and can't even refresh their email, far less try out new apps, thanks to the endless stream of images.

Now, there are ways to free up some space manually, whether by cleaning up photos on an iPhone or by clearing up caches on Android, and you can also use a number of apps on Android that can identify the different types of content that you have, and help you to delete it. Magic Cleaner - which recently launched an updated version that doesn't just look at WhatsApp pictures rather all the images on your phone - lets you remove junk images simply and easily, on both iOS, and Android.

It's an attractive idea, but the first time we heard about the app, we worried about the safety and privacy of letting a third party access every single photo that's present on our phones. To find out more about how the app works, and how secure the images being scanned are, we spoke with Romil Mittal, the founder of Delhi-based Siftr Labs, which made Magic Cleaner.

"Security is an absolutely valid concern, and it's something that we take very seriously, and we've ensured that the user has nothing to be concerned about," says Mittal. "The fact is that the images aren't being uploaded at all. We try and avoid that altogether, but if we have to analyse an image from your phone, we only upload a thumbnail of it, and once it's analysed, we remove the image from our servers."

According to Mittal, the way Magic Cleaner works to ensure the security and privacy of its users is a three step process. First, it tries to see if the image that it's checking is a common forward that it's encountered before. To do this, the app creates a checksum - a mathematical formula that's derived from the image, but can't be used to reconstruct the image if intercepted - and sends that to the service. This is similar to the technology that Shoto uses to help share albums with friends, without uploading the images.

"What we realised is that a lot of these forwards, the images that are filling up your phone, will also be on a friend's phone," explains Mittal. "So, instead of having to check every image, we can first quickly check if it's already been detected as spam. We have a database of some 3 crore images - these aren't the original images, but the checksums, so if your image checksum matches one of these then we can mark it as spam."

That seems like a fairly straightforward process. Of course, building up this database of images to discard happens by collecting new images. So what happens if the checksum of your image isn't found on Siftr's servers? "At this point we upload a 100x100 pixel thumbnail, not your original image, and this gets analysed," said Mittal, "and once that is completed, we store the checksum if it's identified as spam, and immediately delete the thumbnail."

By doing this, Siftr is firstly ensuring that no high-detail image of yours that you deem private is being uploaded at all. Secondly, according to Mittal, these tiny thumbnail images are not saved by Siftr anywhere, nor are they accessible to anyone in the company. So even if you have any sensitive content, it's not being exposed to anyone, according to the company. The actual analysis of the thumbnail image happens automatically, using an artificial intelligence process and not by any human intervention, Siftr says.

All of this sounds good, but if you've not heard of the company, then what it's asking for might seem like a lot. The app asks for access to your accounts, your contacts, your phone's status, to be able to read all your files, check if your Wi-Fi is connected, receive data from the Internet, and full network access. This isn't unusual at all, and there are good reasons - harmless, innocuous reasons - for all those permissions. But how comfortable would you feel about giving this access?

Most of us hand over all of this and more to Google the moment we use an Android phone. Sign up for Google Photos, and all your images are being uploaded - in full resolution. But Magic Cleaner is a free app from an Indian startup, so why should you trust it? Well, for one thing, the company doesn't plan to use the intelligence from your images to make money - instead, monetisation shall come through ads in the app, and through in-app purchases that include more filtering options.

And while there are certainly going to be people who will have questions about whether or not to trust the app, there are quite a few people who are already using it. Magic Cleaner just launched on iOS, but the Android app has already been downloaded 60,000 times according to Siftr. It could make your phone run more quickly, and free up space for apps; would you trust it with all your pictures?