Rust limitation no longer applies; warning about circom/arkworks diff

README.md

@@ -65,9 +65,12 @@ Tests require the following installed:
 - [x] Proof generations and verification using Arkworks
 - [ ] CLI for common operations
 
-## Known limitations
+## Notes
 
-Currently, due to an issue in our upstream (https://github.com/wasmerio/wasmer/issues/4072), this crate works as expected only up to Rust version `1.67.0`; in newer Rust versions, `wasmer` is currently unsound.
+The prover key generated by circom differs from the one generated by arkworks' groth16 library. While the format is the same, it represents different values.
+Circom 'prepares' the powers of tau by converting them to Lagrange base, i.e. from `s^i.G` -> `L_i(s).G`. This affects the witness generation process, and the caller needs to ensure the correct `R1CSToQAP` implementer is used:
+- use [`CircomReduction`](https://github.com/arkworks-rs/circom-compat/blob/b892c62597687c23341cda1e8e89d58bb6428f36/src/circom/qap.rs#L12) for working with circom-generated files,
+- use [`LibsnarkReduction`](https://github.com/arkworks-rs/groth16/blob/5272c935bda290a24cd18d0a3f994b0af70d5f27/src/r1cs_to_qap.rs#L101) for setup produced using the arkworks backend.
 
 ## Acknowledgements