Precompiled optimizations and ecrecover refactor

[hecmas]

Contents

This PR contains the following significative optimizations:

Commit 718b4f5e5947:

• ecMul.zkasm calls to ecAdd.zkasm now avoid unnecessary checks.
• Added a new file doublePointBN254.zkasm to perform doublings.

Commit 586ca2067565:

• ecMul.zkasm now does not use any binary to perform the scalar k reconstruction.
• A new file bitwiseReconstruction.zkasm has been added to allow "fill in" the missing bits of a particular $256$-bit number.

Counters:

• Added counters explicitly for ecAdd, ecMul and ecPairing.
• Some files renaming, to be more consistent with the theory; e.g., instead of scalarMulBN254, we now use scalarMulFP2BN254 to put emphasy on the underlying finite field.
• All scalar reconstructions have been optimized with the slogan: "focus on verifying, not computing".
• Minor optimizations and reorganizations of the code.
• A new function has been added to perform point scalar multiplication by $6 x^2$ directly, where $x$ is the BN254 generator parameter.

EcRecover Refactor: A complete refactor of the ecrecover folder has been done, along with some major optimizations to the double scalar multiplication needed for the public key recovery. See the PR for more details.

Commit 96c24911d introduces a significant improvement (in the sense of number of steps) of the dblScalarMulSecp256k1 function. In particular, in order to avoid using memory variables that are used to reconstruct the scalars, we use small registers RCX and HASHPOS for this end, which are reset every 32-bit cycle.

• Importantly, the file sm_main_exec.js of the proverjs needs to be corrected, since the fe2n() function is incorrectly throwing an error when the small registers are larger than 31 bits.

[sonarqubecloud]

Quality Gate passed

Kudos, no new issues were introduced!

0 New issues
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[hecmas]

Splited between #327 and #328