Why I’m not a fan of smartphones with fingerprint reader

Smartphone has become a staple for most people, from entry-level Android phones to high-end iPhones that can cost close to a lakh. But these devices have evolved from basic calling and texting devices to warehouses for a lot of important personal and even financial information. Right now you are using virtual wallets to top up your mobile phone balance, but soon it might replace your credit or debit card while shopping. But how do you protect this sensitive information?

So far, we’ve had to rely on passwords, PINs, patterns, or keystrokes. These are still persistent, but they are a single layer of security that can be beaten with a little guesswork or some social engineering. That’s where fingerprint sensors come in – Apple has taken the lead, but many Android phones, including those from HTC and Samsung, have this technology now too. The use of fingerprint detection technology has taken off in mobiles as it enables convenient yet reliable security of our data.

That’s the idea but the reality is a bit different. When a phone that supports the fingerprint sensor is turned on, it initially asks the user to enter fingerprint data so that their phone is secure. The sensors trace the fingerprint and store it in the phone’s local memory. While Apple’s phones have done a better job of securing fingerprints, none are completely secure.

In fact, in Android phones, fingerprints are stored as unencrypted files in local storage and hence are easily readable through sequenced codes of alphabets. With that in mind, your phone might actually be a lot less secure than you imagine. For example, mobile phone manufacturers have created a secure platform to encrypt fingerprint data known as TrustZone, but this has also been hacked into high-end smartphones from HTC and Samsung.

At a conference on the Blackhat hack, researchers exposed the security issues the phones were facing:

Confusions in scanner authorization processes that could allow hackers to install malware and bypass payment services fingerprint security features

Trust zone design flaws in the fingerprint sensor that allow eavesdropping attacks to remotely harvest user fingerprints

Pre-integrated fingerprint backdoors that can be used to hijack fingerprint-protected mobile payments and collect smartphone user data.

In other words, we can assume that our fingerprints aren’t really secure. But if so, then aren’t they worse than passwords? After all, we are repeatedly advised to change our passwords and PINs regularly, and never to use the same password for multiple devices or accounts. In the case of a fingerprint sensor, you can do much less to ensure variability. Once your fingerprint data is available, your security is compromised on all devices at all times.

Apple and Google could bring more features to add security, but the possibility of breaching that security remains. Unless you can achieve “perfect security” for fingerprints, this isn’t really a good solution. Fingerprints cannot be changed by the user to protect their data. The same fingerprints will unlock your phone, desktop, and any other point where biometrics are used.

And that means everything is as secure as the least secure thing you use – if one device is hacked, all of your devices have their locks unlocked. That old cell phone you had is going to be a storehouse of your private data, including a password for every device you own or work with. You can’t choose your fingerprint, so what are you supposed to do about it?

When you consider that governments around the world are also starting to use biometric citizen records for purposes such as visa verification, it becomes even more serious. For one thing, there is little data on how the government will secure this information. At the same time, if an old phone could unlock your fingerprint, it could be misused for identity theft – when your finger is your key at passport control, do you really want your phone to have the same “password” ?