Legacy Wallet (ECDSA baseline)

Generate keys

# ECDSA (default)
node wallet.js
# Dilithium‑5 (post‑quantum)
node wallet.js --alg dilithium

| Test                       | Purpose                                        |
| -------------------------- | ---------------------------------------------- |
| **keygen → sign → verify** | “Happy path”—prove Dilithium works.            |
| **tampering**              | Make sure forged messages fail.                |
| **0-byte / 4 MB**          | Edge-cases: empty string and huge blob.        |
| **save ↔ load**            | File persistence didn’t corrupt keys.          |
| **wrong publicKey**        | Signature can’t be validated with another key. |

### Quantum-Risk Scan

| Metric | Day 3 | Day 9 |
|--------|-------|-------|
| **Risk score** | 30 / 100 | **0 / 100** |
| PQ algorithms detected | — | Dilithium-5 |
| Legacy ECDSA exposure | High | Mitigated (ECDSA_SHOR weight 0) |