First on-silicon Semaphore v4 verifier for microcontrollers (no_std Rust, ~1s on a $7 chip)

[Niek-Kamer]

Hi! I built a no_std Rust verifier for Semaphore v4 proofs that runs on microcontrollers in the 128 KB SRAM tier (hardware wallet class chips: nRF52, STM32F4, Ledger ST33, etc.).

Took a real Semaphore v4.14.2 proof (Merkle depth 10, 4 public inputs) generated by snarkjs under the production trusted setup, verified it on a Raspberry Pi Pico 2 W. Same VK + proof bytes that the Ethereum Semaphore precompile accepts, unmodified.

Numbers, on-device:

• Cortex-M33: 1,176 ms (761 ms with hand-written UMAAL asm)
• RISC-V Hazard3: 1,564 ms
• Total RAM during verify: ~97 KB

As far as I can tell this is the first public no_std Rust Semaphore verifier in this SRAM tier. Repo (MIT/Apache): https://github.com/Niek-Kamer/zkmcu

Curious whether this is interesting to the Semaphore team happy to write it up as a technical report, integrate it into the benchmarks repo, or chat about what would make it more useful for the ecosystem.