security: side-channel safety & constant-time operations #12
Description
Guarantee constant-time arithmetic on secret values to prevent timing attacks.
Approach
- Integrate the subtle crate for constant-time comparisons and conditionals.
- Audit all field and share operations for secret-dependent branches.
- Add ct_eq and Choice where needed.
Tasks
- Integrate subtle crate.
- Replace unsafe branches with subtle conditionals.
- Add timing tests or analysis harness.
- Update SECURITY.md.