Do you know which of your passwords hackers have stolen? If you don’t, it’s never too late to check. In any case, you probably remember the times you’ve lost your phone much more clearly than all the times you’ve been hacked.
That’s the reasoning behind the security argument that Rivetz CEO Steven Sprague presented today at MWC Barcelona (formerly called Mobile World Congress): we should trust people to keep track of their devices, but not their passwords.
Hardware-makers have for years built so-called Trusted Execution Environments (TEEs), which are walled-off parts of processors designed to prevent everyday applications or programs from accessing our most sensitive information. Intel offers one called SGX and ARM has one called Trustzone. "This is useful functionality to have,” says Roland van Rijswijk-Deij of the University of Twente in The Netherlands. “In theory, the TEE can protect against applications on the ‘normal’ OS gaining access to credentials.”
To replace traditional passwords, Sprague’s startup puts one of a user’s private keys into the TEE and another onto a user’s SIM card. That means that any message encrypted with both keys must have come from a sender in possession of the working device and an active account with their mobile network operator.
That makes the message very reliable—a bank can be more confident that message came from its client and not from a hacker, for example. And, those messages can be stored in a blockchain that verifies that the messages were created in that hardware safe space, and that nothing has happened to the message since its creation.
That reliability makes the service attractive to partners such as Civic, which is using Rivetz to allow customers to choose which parts of their identity, such as their age, they’d like to reveal to online businesses, without needing to give away more information than necessary.
Involving the SIM card makes it possible for your operator to offer another handy service: If you lose your device, you can contact your carrier, verify your identity to them through other trusted devices, and remotely block the missing device. Unlike when you report a credit card as stolen, if you later recover the device, you can reactivate it from one of those other trusted devices.
“We are a collection of devices, not any one of them,” Sprague said during his presentation.
But Rivetz, like any feature involving TEEs, only works on certain devices. For now, Rivetz offers its software, which sits sandwiched between hardware and apps written by third parties via a software development kit, only on certain versions of the Android operating system. That means if you don’t have a compatible device on you, you cannot log into a Rivetz-secured application from a different device, such as a work computer or a friend’s phone.
It’s also not easy for normal users to verify whether a given TEE is actually safe, van Rijswijk-Deij says: "The TEE might be a perfectly secure design, but this is difficult for users to establish. Effectively, you're going to have to trust [the manufacturer’s] claim that it is secure, which can be fair: trust has to start somewhere.”
Sprague says those are worthwhile tradeoffs and that banks and others should have made them long ago, instead of focusing on systems involving usernames and passwords so that anybody could log in from any device. “It’s not about the identity of humans,” he told IEEE Spectrum, “it’s about the identity of things.”