Add property-based tests for HMAC signature verification edge cases

[mikewheeleer]

Description

Webhook signature verification in src/webhookDelivery.ts needs adversarial coverage. Add property-based tests that fuzz signatures, headers, and bodies to ensure no malformed input bypasses verification or throws unhandled errors.

Requirements and context

• Use generated inputs (random bytes, truncated signatures, wrong-length HMACs, mismatched encodings) to assert rejection.
• Confirm constant-time comparison behavior and that errors route through safeErrors.ts.
• Acceptance: fuzz suite runs deterministically with a fixed seed; zero accepted forgeries; branch coverage on verify path >= 95%.

Suggested execution

• Fork the repo and create a branch:
  • git checkout -b test/hmac-property-tests
• Implement changes:
  • src/webhookDelivery.ts
  • Tests: src/webhookDelivery.test.ts
  • Docs: docs/webhook-signature-verification.md
  • Include TSDoc/NatSpec-style doc comments
  • Validate security assumptions (input validation, auth, signature verification, secret redaction, idempotency)

Test and commit

• Run tests: npm test (coverage: npm run test:ci)
• Cover edge cases
• Include test output and security notes in the PR

Example commit message

test(webhooks): add property-based HMAC verification tests

Guidelines

• Minimum 95% line coverage on new/changed code
• No secrets in repo; use .env + deployment secrets only
• Clear documentation
• Timeframe: 96 hours from assignment

[Jayking40]

@Jayking40 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I'd like to volunteer for the issue "Add property-based tests for HMAC signature verification edge cases" (Talenttrust/Talenttrust-Backend). As a contributor with experience in typescript and jest, I'm confident in implementing property-based tests to ensure robust HMAC signature verification. I'll focus on fuzzing signatures, headers, and bodies to prevent malformed inputs from bypassing verification or throwing unhandled errors. I estimate completing the task within the next 18 hours (@Jayking40).

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Jayking40 to this issue.

[drips-wave]

Congratulations, @Jayking40! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @Jayking40: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

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