Show HN: Building a future where security checks leave no permanent trails

1 point

4 months ago

Every time someone checks if a password has been breached, a permanent record is created: this person checked this password at this time.

(All code is open-source, MIT licensed)

I've been exploring whether we can design a different future—one where security doesn't require this privacy trade-off. The Credential Shield Protocol (CSP) is a step in that direction: it allows checking password breaches without the checking service learning whether your password was actually found.

The key insight: send only a fragment (prefix) of the password hash. The server returns possible matches from breach databases, but the actual verification happens on your device. The server is intentionally kept "blind."

What's available today: • RFC-style draft with formal analysis • Complete reference implementation (Node.js) • Test vectors and collision probability analysis

This is early-stage protocol research, not a product. I'm looking for: - Cryptographic review of the approach - Feedback on the threat model - Implementation critique - Discussion on whether this future is worth building toward

GitHub: https://github.com/IAmAxolotl-04/password-smoke-detector RFC Draft: https://github.com/IAmAxolotl-04/password-smoke-detector/tre...

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