Nostr Web Client

The ESP32 used by these signers is not a very secure chip. Most MCUs in general including STM32, ESP32, RP2350 etc lack security features.

While most devices use secure elements, they export the key to the insecure MCU once the boot is complete.

This requires an on-SE signing solution. I am currently building the first secure element designed for Nostr and Bitcoin, ensuring your keys never leave the device.

This is based on an EAL6+ chip from a large SE vendor that also protects billions of credit cards and passports.

There are 2 distinct possible use cases:

- A USB stick you can plug into a home server like an Umbrel or a Start9, that provides a secure storage for your keys and a trusted anchor for future use cases, and can allow most actions without review.

- The HWW device I am working on will be able to store and handle Nostr key operations with manual approval for the more sensitive event kinds. This also uses a security-hardened MCU.

frphank 1mo ago 💬 2

> This is based on an EAL6+ chip from a large SE vendor that also protects billions of credit cards and passports.

You mentioned the NXP SE050 before which is marketed as an IoT chip ... Nitrokey uses the NXP P5DF081 which is more geared towards smart card use but otherwise not much different.

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Discussion

semisol 1mo ago 💬 1

SmartMX1 (P5 series) is a dinosaur. SmartMx2, the successor, was introduced in about 2010 and it is at P71/SmartMX3 now.

SE050 is similar to the Infineon Optiga ones. Both are better than ATECC.

The problem is there is no SEs supporting Bitcoin algorithms, or content-aware signing (so you can for example block a Request to Vanish event from ever being signed)

frphank 1mo ago

Not sure what's so special about Bitcoin algorithms other than the koblitz curve but neither do I care.

As for content aware signing not the role of the SE to my knowledge.