Chaos, Progress In Mobile Payment Security

Rapid transitions have stalled some development efforts, limited others, but improved security is on the way.

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Semiconductor suppliers and their embedded software partners, internally and externally, have made tremendous strides in recent years supporting secure mobile payment processing.

It hasn’t been easy. Or simple. And it’s still evolving.

The result of those efforts, which is now set to play an increasingly important and widespread commercial role in 2017, are trusted execution environment technologies that physically separate and isolate transaction data and processing from the rest of a device’s hardware and software.

Arm TrustZone, a technology it had the foresight to begin working in at least 15 years ago, is central to this scheme for a number of chip companies.

“Mobile payments is driving so much of the technologies in security today,” said Sy Choudhury, senior director of product management for Qualcomm Technologies, the wireless giant’s chipset business. Qualcomm has shipped hundreds of millions of ARM-based mobile phone processor chipsets. The Cortex A7-9 and now the M8 based devices, which combined have very high share in mobile computing, have TrustZone.

“Hollywood, with its content protection, used to drive security requirements,” said Choudhury. “But now it’s transactions and finance. Banks and traditional credit card processing companies, as well as the new ‘wallets’, are really pushing the security features of our silicon as well as the embedded software.”

A complex ecosystem
Choudhury at Qualcomm and other key players like Trustonic, the joint venture of ARM and Gemalto, based in Cambridge, U.K., Rambus’ BellID group based in the Netherlands, and Mentor Graphics’ embedded software division paint a complex picture of the ecosystem they support.

Within this ecosystem are a number of well-known and lesser-known players:

• The largest banks, including Barclaycard and Bank of America;
• EMVCo the standards and specifications consortium for the world’s credit card processors, including MasterCard, VISA and American Express/Discover;
• A long list of wireless communications carriers;
• “Wallets” such as ApplePay, SamsungPay and AndroidPay;
• “Over-the-top” payment modes, including TM, AliPay, WeChatPay, JioMoney and Pay, which are becoming a huge factor in China and India.

Screen Shot 2017-01-31 at 3.01.41 PM

SamsungPay. Source: Samsung

All of these of course owe a debt to the secure mobile payment mode that came before them, smart cards. Gemalto, a part owner of Trustonic, is the successor to Gemplus, a name familiar to anyone who followed the semiconductor business in the 1990s. Today Gemalto is involved in a host of technologies for securing and processing transactions that consumers make on the go.

“The infrastructure and technology is complex,” said Paul Butterworth, strategic marketing manager at Trustonic. Butterworth has spent 25 years in this ecosystem, and he’s had his share of setbacks watching promising mobile payment plans not quite take off. “I’ve been a part of 40 different pilot programs. We’ve had the banks and the mobile operators cooperating extensively to have a trusted services manager, to manage the SIM on the phone, to provision [transaction detail] to that SIM. The bank would have one part, the mobile operator would have another part. In the end, the mobile network providers wanted more revenue share than the banks would pay.”

Progress slowed for a while after that. “So then, Google brought out its KitKat technology, which allowed a device to emulate the SIM,” he said. “Players brought up new cloud-based specs. We got tokenization rather than real card numbers, with limited use keys so you have even more security. All was looking positive. Then Apple threw in ApplePay. They re-wrote the rules. That really forced the card makers to create the big tokenization platforms. The [credit card processors] loved this. They get back into every transaction.”

Trusted execution environments
Trustonic provides the trusted execution environment (TEE) in 800 million mobile devices, and can support “anything with an ARM chip in it.”

But Qualcomm is intent on that being the beginning, not the end of the story on TEEs. Choudhury said biometric security, using fingerprints and iris and face scanning, is spurring mobile payments to spread across all regions right now. “First it was iPhone and higher tier Galaxy handsets, phones from Sharp and Fujitsu in Japan. That really was an inflection point. And that’s a trend we see continuing.”

Choudhury, who worked in RTOSes at Wind River Systems prior to joining Qualcomm, said there are three main considerations and they are all driving the semiconductor and chipset technology features that allow for secure mobile payments for everybody with a smart phone.

“One, how do you make that app, the digital wallet or the banking app, how you make that more secure? Two, how do you securely authenticate the user?… and three, and this is the more emerging area, how do you attest that the device is what you think it is, that it hasn’t been compromised in any way?” said Choudhury.

All Qualcomm SoCs, including the just-announced Snapdragon 835, ship with the ability to have “Non-Secure Mode” (normal mode) and “Secure Mode” (TrustZone mode) to facilitate secure communications and transactions. It integrates ARM Cortex M V8.

“When that TrustZone capability has been implemented, you have hard coding protecting those resources. It could be I/O, it could be memory, but it’s physically not accessible to the normal world,” said Andrew Caples, product marketing manager for Mentor Graphics’ Nucleus RTOS embedded software. “It creates that hard separation. You isolate the Linux vs. the RTOS vs. the bare metal.”

The Qualcomm Secure Execution Environment (QSEE) has been out for about five years. “If you are a mobile banking app, what’s increasingly happening is they are not running that app as solely one running on Android,” Choudhury said. “You run the app on top of the secure execution environment. Then you have even better security. But security is always about layers.”

One of those layers can involve obfuscation technology to prevent side-channel attacks, one of the best understood and least difficult hardware attack vectors because it can be done by applying an external probe connected to a standard oscilloscope. The problem is that solutions typically involve active electronic obfuscation, so they add circuitry, cost, and can increase latency, said Lee Sun, field applications engineer at Kilopass. As a result, using these kinds of solutions needs to be highly targeted.

“For one-time programmable antifuse memory, this isn’t a problem because most times when you store keys, that doesn’t create a performance bottleneck,” Sun said. “But the tradeoff is that someone cannot look inside to determine content. You can add features around bit cells to balance power distribution, detect glitches, and add random data into the bit stream to prevent that.”

Biometrics, multi-factor ID
Qualcomm also designed secure buses for transferring data that executes in the QSEE to the flash memory for secure storage. This is how the authentication of a fingerprint is done.

“Most people think that fingerprint by definition is secure, but it’s really a small photocopier,” he explained. “Take a picture, digitize it, tokenize it. But the sensor also has to connect to the processor through a secure bus. Synaptics [the sensor company] code has to ride on the QSEE. Once you have extracted your fingerprint, you have to store that in a secure place. The fingerprint card talks to a portion of a flash file system—what’s called a replay protected memory block, or RPMB. It’s a subset of the flash memory that is more secure,” said Choudhury. Handling the data this way means the flash memory for its part does not have to any special security features designed in, which saves the handset maker time and money.

Qualcomm was poised to celebrate in 2016, as all of this technology enabled the mobile industry’s first commercial and consumer eye iris-based authentication in the Galaxy Note 7. Unfortunately, this was overshadowed by the widely publicized overheating issues, which were related to some aggressive engineering decisions on the capacity of the lithium ion batteries in the phone rather errors in semiconductor engineering.

But later this month at Mobile World Congress in Barcelona, the Galaxy 8 will debut. Iris authentication for transactions and for device security and locking will be there, too.

“We will see lots more of this in 2017, ” said Choudhury. “The Holy Grail is multi-factor authentication. Your fingerprint and your iris are checked before you make a payment. That’s what the banks want for high value payments. You would have to do both…. And you better have a secure pipeline underneath it.”

Another consideration is device attestation, and all of the semiconductor suppliers and embedded software suppliers have worked on this, as well. “Is their malware running on it? Have any of those been changed or spoofed in any way?” asks Choudhury. This comes into play for mobile payments, and also the enterprise. “It’s fraud and risk control for mobile payments, but in the enterprise it’s protecting trade secrets. We accomplish root kit detection. How would you know of a malicious act? Because we are behind that firewall, we can monitor whether the Android OS has been rooted. Even though an app could access time, location, OS version, you could do that more directly from hardware, from the secure side itself.”

The Snapdragon 835 has a technology built in called the Haven token, he said. “It’s a device ‘health report card.’ We encrypt and sign that file. We sign and encrypt it with a hardware key from the chip itself, and that attests that the information inside the packet is good information, and when it’s in transit from the calling app to the server it’s protected so there is no man in the middle attacks.” The Haven token functionality will be enabled on multiple OSes, he added, and that’s been driven by the mobile payments industry.

“Almost all OEMs take advantage of the secure boot functionality in our chips now. That was not the case three or four years ago. Of course, in our hardware, we have hardware crypto engines. That’s more holistic to all use cases not just payments, but they are fundamental to it,” said Choudhury.

Crypto engines, near-field communications

The crypto engines are a key component of what brought Rambus further into this world, when it bought the Dutch company BellID about a year ago. BellID’s roots are in managing credentials on smart cards, something they started to do in 1993, notes Andre Stoorvogel, the company’s head of marketing.

“In 2008 we really saw the potential of moving the data on a chip card to a mobile phone,” Stoorvogel said. “We never expected it to take this long to achieve this kind of tipping point. We thought by 2012, everybody would be using it.”

The same dynamic that Butterworth at Trustonic talks about came into play, where the mobile carriers and the banks could not come to terms.

Payments based on near-field communications (NFC) were poised to accomplish what many wanted to see. But Apple made a key and important decision to close off access to the NFC chip. It was ApplePay or the highway.

“2013 saw a huge turning point when we got host card emulation. You are putting that secure element in the cloud,” said Stoorvogel. “The banks could have their own server with their own secure element. They can remotely communicate with the customer’s phone. Suddenly, they could bypass the carriers and the device makers.”

Rambus BellID provides software for the host card emulation, and for the provisioning of cards to a customer’s phone.

“We offer all the tokenization technology. It generates the token, issues the token in the transaction, and it keeps track of all the tokens that have been generated. Was there a problem with a certain transaction? The bank can go back and check.” The log links back to the original credit card number.

BellID supplies this software connector to ApplePay, AndroidPay and SamsungPay. However, payments for metro transportation aren’t able to ride on this technology. “The challenge with transportation is speed,” said Stoorvogel. “Within milliseconds you need to have this approval. It’s been quite challenging to come up with a solution there.”

In London, he said, Apple has gone live with metro ride payments from ApplePay. But that will likely be much harder to replicate North American cities mainly due to lack of standards. U.S. users also are uniquely tied to their credit cards. In India and China, the pay by smart phone technologies don’t have to compete with that entrenched psychology and force of habit.

Conclusion
Trying to pick a winner in this market and develop semiconductor technology to tap that formula has been extremely difficult. There are too many companies with a stake in this market, and the technology itself is evolving too quickly.

But there is a widespread recognition that something needs to be done, as well as a number of competing technologies that show merit. Many of these will begin rolling out this year, at which point they can be market-tested to see whether they can withstand an increasingly devious and highly advanced network of hackers — and for how long. What’s becoming clear in this market segment is nothing is for certain, nothing lasts forever, and given enough time and effort, nothing is bulletproof. But for technology to progress, it has to at least increase the time it takes for hackers to breach a system while also limiting the value of the rewards once they do breach it.

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