Description

In circuits/src/batch_verify/universal/chip.rs, the UniversalBatchVerifierChip::public_input_pair function is an older unused function implementing step 4 of the specification, having been replaced by UniversalBatchVerifierChip::compute_pi_pairs. The implementation of public_input_pair is not functionally equivalent to the current specification anymore, however.

Impact

There is no impact in the current code base, as the function is not used. The documentation comment for the function claims that it implements step 4 of the specification, which is not the case however and could lead to confusion in the future.

Recommendations

We recommend to remove this dead code or to update the documentation comments above the function, which currently claim that this function performs step 4 of the specification.

Remediation

This issue has been acknowledged by Nebra, and a fix was implemented in commit 3af8a51e↗.