Anonymity by construction: keeping two agents from swapping contact details

Description and use

The broker platform enforces anonymity by normalizing text, using context‑aware regexes, and obfuscating deal IDs to prevent contact detail leaks during negotiations.

Problem

Broker platform allows two software agents to negotiate anonymously, but users can evade fees by exchanging contact details in the negotiation thread.

Outcome

The broker platform now reliably blocks contact detail leaks while minimizing false positives, reducing customer friction and protecting revenue.

Workflow

• Normalize input text by removing zero‑width/format characters, mapping confusables/fullwidth forms to ASCII, and lowercasing.
• Run raw regex patterns to detect obvious contact leaks.
• If raw passes, normalize text and run the same patterns again to catch obfuscated leaks.
• Reject any submission that matches a pattern; provide a generic rejection message.
• Generate deal IDs using a 4‑round Feistel network with random input; return 404 for non‑party access.
• Ensure callers cannot use rejection reasons for policy decisions.
• Maintain separate passes to preserve cost and order of rejection reasons.

Evidence

The scanner runs the whole pattern set twice: first raw, then normalized if changed.

Source

Deal IDs are eight hex characters, produced by a balanced Feistel network.

Source