Null Square

Tag cloning in the wild 🟡

RFID/NFC cloning lets attackers read and duplicate proximity tags.
Here’s what it is and how to harden your setup.

Why it matters: doors, payments, and transit rely on these tags—weak configs are easy wins.

- Use modern tags with mutual authentication and strong cryptography.
- Retire legacy protocols without encryption.
- Diversify keys per tag and enforce fine-grained access rules.
- Reduce read range with tuned power and shielding; secure reader placement.
- Monitor access logs and rotate credentials on anomalies.

✅ Strong protocols plus good configuration beat cheap cloners.

False positives, true speed ✨

A Bloom filter is a compact data structure for set membership.
It trades tiny false positives for huge memory savings.

Why it matters: fast lookups at scale without storing full items.

- pick hash count to hit your target false positive rate
- size the bit array for peak load, not average
- avoid deletions unless using a counting variant
- watch saturation; rebuild when the bit density creeps up

✅ Use Bloom filters when you need ultra-light membership checks and can tolerate rare false positives.

🛡️ Passkeys stop phishing at the root.

Passkeys (WebAuthn/FIDO2) use public‑key cryptography instead of passwords. Your credential lives in secure hardware (phone, TPM, or a roaming security key).

Why it matters: no shared secrets to steal; sign‑ins are bound to the site’s origin.

- Register at least two authenticators (phone + security key) for redundancy.
- Require user verification (biometric or PIN) and disable weak fallback factors.
- Prefer discoverable credentials for true passwordless where supported.
- Keep a spare key offline; enable secure sync with strong device lock if you use cloud passkeys.
- Admins: enforce WebAuthn in your IdP, restrict origins, and review attestation policy.

✅ Passkeys cut phishing and reuse risk while making login faster.