Security has become a top priority in the IoT era, especially at the hardware level. Maxim hopes to bring both security and low power consumption to IoT applications with its cryptographic processors.As the world becomes more digital, so do the risks and fears of cybersecurity. Only the security of software design can no longer meet the needs of security, but it is increasingly necessary to consider security when designing hardware, even at the silicon level.
Maxim Integrated (now officially part of ADI) has been working hard to accomplish this. The company has released a new low-power cryptographic controller that leverages Physical Unclonable Function (PUF) technology to improve hardware security. This article will analyze the characteristics of PUF technology and Maxim's latest encryption unit.
About PUF
Before we dive into what Maxim has released, let's talk about PUF, one of the most important technologies in hardware security.
PUF is a hardware security technology that exploits inherent variation in device characteristics to produce unclonable, unique device responses to a given input. The PUF's response is unique, random, and repeatable, and it can aid in the generation and "storage" of encryption keys, making them extremely difficult to crack at the hardware or software level.
A major benefit of PUF is that it's a non-volatile technology, but it also doesn't physically "store" keys.
Instead, PUFs create keys in a challenge-response fashion when needed, after which the keys are wiped almost instantaneously. As Maxim Integrated said. "There is always a key, but you can never see it." Using PUF enables strong and highly secure cryptographic key storage at the hardware level, which is why Maxim included it in its security platform ChipDNA PUF.
Maxim's ChipDNA PUF
Maxim Integrated has invested heavily in PUF technology and its flagship product is ChipDNA PUF.
ChipDNA works by exploiting random variations and mismatches in analog properties that naturally occur in CMOS designs. The figure below shows a simplified block diagram of the PUF architecture with an example key size of 128 bits.
The image above shows a 16 x 16 array of 256 analog PUF elements combined into 128 pairs. Due to process variations, each component exhibits random I/V characteristics, and Maxim then generates binary values through circuit-level comparisons of each pair of components. This process is repeated for all 128 pairs, resulting in a unique 128-bit key output.
Most importantly, as a hardware-level security feature, ChipDNA PUF is completely immune to all known invasive attacks (i.e., probes) and thus can be a way to provide hardware-level security.
MAXQ1065 = Low Power and Security
Maxim's newest security coprocessor, the MAXQ1065, is an ultra-low-power cryptographic controller for the Internet of Things.
In IoT applications, low power consumption is one of the most important aspects. The MAXQ1065 achieves this with <100nA standby power consumption, which Maxim says can reduce power consumption by a factor of 30 compared to similar products.
The device is designed to provide several security measures, including root of trust, mutual authentication, data confidentiality and integrity, and secure boot.
Building on this, the MAXQ1065 utilizes ChipDNA PUF technology to prevent device-level security attacks. Other hardware security measures include.
A true random number generator (TRNG)
A TLS/DTLS 1.2 handshake and record layer
An 8 kB user data secure memory
In the future, Maxim hopes to see the MAXQ1065 used in IoT devices such as supervisory control and data acquisition (SCADA), medical equipment, building and home automation, smart cities, and smart metering. As the world becomes more connected, the continued search for low-power and high-security processors will be critical.
