How do I verify a signature signed using Polkadot.js app with rust code

Question

I am trying to write a discord bot using rust/serenity to verify signature signed using polkadot.js app. I use schnorrkel crate, wrap the message in <Bytes>...</Bytes> and use the verify method to do this. Everything works as expected for sr25519 signatures. But if the user has generated an ed25519 keypair, this fails.

How can I verify ed25519 signatures? Can I figure out from the signature (or public key) if it has been generated by a ed25519 keypair? I tried with ed25519_dalek crate but could not make it work.

Answer 1

The JS side actually operates via WASM (if available, which is 99.99% of the cases). When using WASM it uses the same ed25519_dalek crate you pointed to.

Specifically here is the Rust/WASM code it uses for ed25519 verification.

(There are WASM and non-WASM tests on the JS libs to ensure that they do match, i.e. the WASM verification should align with a pure JS implementation as well)