
NOR Flash supports data encryption for secure vehicles
The fusion of NOR storage and security is based on the insight that connected systems must increasingly be protected against cyber attacks. End-to-end protection is therefore a growing concern for system providers, explained Rainer Hoehler, head of The Cypress Flash business unit (and now working for Infineon).
Semper Secure NOR flash memories are based on the intelligent memory architecture of Semper NOR flash; this architecture has proven itself with its robust functionality in practical use and is the first memory solution to combine the aspects of security against unauthorized memory access with functional security in a single NOR flash device. It thus offers the level of security and reliability required by connected automotive systems such as ADAS ECUs. For applications in industrial and communication systems the requirements are similar.
A secure NOR flash solution is especially important if the NOR flash is placed outside a processor, making it vulnerable to a variety of attacks. Semper Secure is the only NOR-Flash solution that provides a hardware-based root-of-trust, which allows a complete end-to-end protection, Hoehler claims. “The software code in the NOR memory of ECUs is often security-relevant; in addition, vehicle manufacturers want to protect this software against unauthorized readout and manipulation.”

The protection of memory contents is also gaining in relevance because the complex ECUs frequently used today in ADAS ECUs usually no longer have an integrated flash area. Therefore, the sensitive program code is stored in external NOR memories – and must then be encrypted accordingly. For this purpose, the storage controller also contains a crypto engine that even supports asymmetric encryption and the associated complex key management. Such a key management is also indispensable for software updates over the air (OTA) which are planned by most major carmakers for future vehicle generations.
During the development of the Semper Secure NOR flash, Cypress was working with a number of semiconductor partners involved in automotive electronics, Hoehler explained. Examples are Texas Instruments, Toshiba, Xilinx and Renesas.
To facilitate system development and integration, Infineon offers a suitable development kit.
The Semper Secure NOR flash family includes AEC-Q100 qualified automotive-grade devices with an extended temperature range of -40 °C to +125 °C, supports 1.8 V and 3.3 V power supplies and is available in 128 Mb, 256 Mb and 512 Mb capacities. Semper Secure NOR flash meets the requirements of the ISO 26262 standard. It is ASIL-B compliant and can be used in systems up to ASIL-D. The implemented EnduraFlex architecture simplifies system design by allowing optimization for partitions with a large number of programming cycles or long storage periods without data loss. The devices are offered with the Quad Serial Peripheral Interface (SPI), Octal SPI and HyperBus interfaces. The Octal and HyperBus interface devices are compliant with the JEDEC eXpanded SPI (xSPI) standard for high-speed x8 NOR serial flash and offer a bandwidth for read operations of up to 400 MByte/s.
Infineon’s 256-Mb Semper-Secure NOR Flash devices are currently being sampled for key customers, with volume production expected in the second quarter of 2021.
More information: www.infineon.com/sempersecure
