fix(abi/mockEncrypt): fix no-op bitmask in generateMockCtHash string hashing

[amathxbt]

Summary

generateMockCtHash in packages/abi/src/mockEncrypt.ts uses hash & hash as a bitmask when hashing strings, with the comment "Convert to 32-bit integer". This is a no-op — x & x === x for any value — so the intended 32-bit truncation never occurs.

Bug

if (typeof data === 'string') {
  let hash = 0n;
  for (let i = 0; i < data.length; i++) {
    const char = data.charCodeAt(i);
    hash = (hash << 5n) - hash + BigInt(char);
    hash = hash & hash;   // ← BUG: hash & hash == hash, this is a no-op!
    //                              Was intended to be: hash & 0xFFFFFFFFn
  }
  return hash < 0n ? -hash : hash;
}

Consequences:

1. The hash accumulates a left-shift of 5 bits per character. For an input string of length N, the intermediate value can reach up to 2^(5*N) bits. A 200-character string produces a hash with ~1000 bits, far exceeding the uint256 (256-bit) size of a ctHash field.
2. When this overflowing bigint is passed as ctHash in an EncryptedInput struct and encoded via abi.encode, Solidity silently truncates it to the lower 256 bits — potentially producing the same ctHash for two different strings (collision), breaking mock test isolation.
3. Mock tests that encrypt string values (e.g., addresses as strings) may produce unexpected results that only manifest at long input lengths.

Fix

Replace hash & hash with the correct 32-bit mask hash & 0xFFFFFFFFn, matching the stated intent of the comment.

[vercel]

@amathxbt is attempting to deploy a commit to the Fhenix Team on Vercel.

A member of the Team first needs to authorize it.

[changeset-bot]

⚠️ No Changeset found

Latest commit: be3837a

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[architect-dev]

Please update so that the CI checks are passing. Also please remove the commented annotation.

Thanks for your contribution 👍

[architect-dev]

Lets remove the annotation, better in the PR description instead of baked into the codebase.

[amathxbt]

Lets remove the annotation, better in the PR description instead of baked into the codebase.

Working on this thanks for your feedback