[WIP] Common objects for Signing

[derekpierre]

Type of PR:

• Bugfix
• Feature
• Documentation
• Other

Required reviews:

• 1
• 2
• 3

What this does:

High-level idea of the changes introduced in this PR.
List relevant API changes (if any), as well as related PRs and issues.

Issues fixed/closed:

• Fixes #...

Why it's needed:

Explain how this PR fits in the greater context of the NuCypher Network.
E.g., if this PR address a nucypher/productdev issue, let reviewers know!

Notes for reviewers:

What should reviewers focus on?
Is there a particular commit/function/section of your PR that requires more attention from reviewers?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 36.88784% with 799 lines in your changes missing coverage. Please review.
✅ Project coverage is 32.70%. Comparing base (e080d33) to head (5490090).

Files with missing lines	Patch %	Lines
nucypher-core-python/src/lib.rs	0.00%	523 Missing ⚠️
nucypher-core/src/signature_request.rs	61.01%	276 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #113      +/-   ##
==========================================
+ Coverage   30.05%   32.70%   +2.64%     
==========================================
  Files          18       19       +1     
  Lines        2349     3605    +1256     
==========================================
+ Hits          706     1179     +473     
- Misses       1643     2426     +783     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[derekpierre]

@KPrasch , do we have some mismatched types here?

I thought this value and others are supposed to be uint256 (based on the spec - https://eips.ethereum.org/EIPS/eip-4337) but are only represented as u128? My understanding is that Rust built-in types only go up to u128.

• Do we need some other library that provides uint256 functionality, or create a type ourselves? eg. https://docs.rs/primitive-types/0.13.1/primitive_types/
• Did you ever look into whether there are existing Rust libraries that already have a representation for UserOperation that we can leverage, as opposed to writing our own? For eg. https://docs.rs/alloy-rpc-types-eth/latest/alloy_rpc_types_eth/ or https://github.com/alchemyplatform/rundler. - I haven't looked into it, just noticed it in a search.

[derekpierre]

^ @KPrasch any thoughts here?

[KPrasch]

2¹²⁸ ≈ 3.4 × 10³⁸ is an astronomically large number :) Ethereum mainnet block gas limit (as of 2025) is on the order of 30 million gas per block (~3 × 10⁷). So even if gas limits grew a trillion-fold, you’d still be nowhere near 2¹²⁸.

From a practical standpoint, u128 is vastly more than enough to represent gas limits or call gas. However, the EIP-4337 spec does defines them as uint256.

That being said, alloy does look like a promising tool here if we want to accept a new dependency.