Background: Attacks on electronic devices and systems such as IOT endpoints, computers, medical devices and infrastructure are on the rise. These attacks not only pose information security and safety hazards to companies and individuals, but also counterfeiting risks to brand name products. To resist such attacks and maintain secure communications, computing and control, new devices are implementing security which depend upon cryptographic “keys”. These keys are used to encrypt/decrypt data as well as create and verify digital signatures. Cryptographic keys are commonly referred to as a “physical unclonable function”, or PUF keys. These keys act as a secret “digital fingerprint” providing a set of random-unique identifying numbers for a specific device that cannot be easily observed, deciphered or copied, preventing an attacker from impersonating a valid device. PUF keys are often 256 bits in length employed to secure and unlock the operation of devices by approved users. The foundation for the secure operation of computing systems is often referred to as “root of trust” which typically utilizes a challenge-response method of authentication. For higher levels of security, root of trust keys are primarily implemented within integrated circuit semiconductor hardware.
While CrossBar’s ReRAM technology has been traditionally utilized for non-volatile memory, the company has recently introduced its unique ReRAM cell technology for the novel use as cryptographic keys for the secure operation of electronic devices and systems.
Advantages of ReRAM PUF: While there are numerous technologies capable of being used as PUF keys, the most common hardware approach available today is to exploit the randomness characteristics of semiconductor SRAM memory (Static Random Access Memory). Unfortunately, SRAM PUF key technology has numerous drawback limiting its level of security and effectiveness as noted in its:
* Lower levels of key randomness,
* High bit error rates,
* Limited tamper and side-channel resistance and
* Longer sensing times.
In contrast, CrossBar’s latest ReRAM PUF cryptographic key technology is enabling a new class of secure devices and systems, addressing many of the issues associated with SRAM PUF. CrossBar’s ReRAM based cryptographic keys have a very high level of randomness, extremely low bit error rate, resistance to invasive attacks and the capability of handling a broad set of environmental characteristics such as temperature, supply voltage and electromagnetic interference due to the inherent physical characteristics of the Resistive RAM technology.
CrossBar’s new ReRAM PUF technology is an ideal candidate for applications requiring both high security (PUF cryptographic keys) and efficient non-volatile memory embedded in semiconductors, which is especially important at foundry nodes less than 28nm where embedded NVM memory (flash memory) is not typically available.