how to store keys securely?

[ezamp]

HI, I'm developing a device (based on uBlox Anna-B112 with nRF52832) that must securely store three 256bit keys. These keys must remain secret and must not be readable by any user, otherwise the security of the device would be compromised.

Is there a software module that allows me to save these keys securely in flash memory? I will definitely have to block access to memory via programmer/debugger but I don't think that's enough.

I think the best solution is to use an external crypto chip. Is there any chip already compatible with the software modules present in the SDK?

Thanks

[Vidar Berg]

Hi,

This does depends on the level of security you require for your product. The easiest and cheapest option is of course to keep the keys in internal flash. But for higher secuity you may consider Infineon's OPTIGA Trust X module. The nRF5 SDK includes the Infineon OPTIGA Trust X Custom Example to demonstrate how it can be integrated. 

Best regards,

Vidar

Edit: Link to a blog post about the infineon module: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/new-in-nrf5-sdk-v15-strong-hardware-based-security-with-infineon-optiga-trust-x-1421904473

[ezamp]

Thanks for the reply, I chose to use the Infineon OPTIGA Trust X. 

Looking at some examples for the SDK17 I noticed that for the pca10040 the I2C pins are indicated as ARDUINO_SCL_PIN (27) and ARDUINO_SDA_PIN(26). If I look at the schematic of the EVK-ANNA-B112 dev kit (www.u-blox.com/.../UBX-18018539) I noted that the I2C uses pins 14 and 15 (I2C according to the arduino socket) and not 26 and 27 as indicated by the example. 

In a week I should get a dev kit for the Optiga Trust X and I will try both pinouts.

Thanks for your help!