What's the best way to wipe a smartphone?

Tech guru Peter Cowley tackled Golfvswag's question...

Peter - First of all you’ve got to understand there's quite a big difference between Android and IOS - so IOS is the Apple operating system; Android has about 75 percent of the market in the world, and IOS most of the rest apart from a few Windows phones, except in the UK actually where they’re about 50/50 - because they have different levels of security built in anyway. So first of all there is a function in all of them to delete or wipe the whole of the contents. But some research was done in Cambridge actually, I think last year, which took a phone - Android phones - and found that you could get data off it again. This is because of something called levelling, wear levelling of the flash memory, where a block of memory is actually not used any longer because it might get worn out. And so to avoid that, I  think there are two possibilities, both of which should be used - well, in different cases. One: if you encrypt it first, the phone, and an IOS phone is encrypted anyway using hardware, but if it’s an Android phone you encrypt it first, then you wipe it, you will almost certainly have removed... there'll be no way of getting at any data at all. First point. With IOS as I say there's a piece of hardware in there and has been for the last nine years or so. Of course the final, which doesn't allow any recycling, is just to get a sledgehammer.

Chris - That works quite well, doesn't it.

Peter - Well I suspect it probably works well but you've still got to break the chip involved. And so if a crime was involved which might involve murder, and it's not completely broken, then it could be cracked.

Chris - You could still read that. Lívia?

Lívia - How do you encrypt the phone?

Peter - The encryption is a software encryption on an Android. There's a switch inside it, so you go into the settings, you'll find ‘encrypt’. The problem about encrypting is that the decrypt process can take time. Which is why on IOS it's done in hardware, it's done as the data is coming out of the memory chip in hardware, and therefore it's done the whole time. So information on an IOS device, an Apple device, is always encrypted. So you'd actually have to force the encryption. Whether there’s a knock-on effect on an Android device we’ve encrypted because of the speed of response, I don't know, because I use Apple.