px-reverse

What problem does it solve?

This skill solves the complex, time-consuming process of reverse-engineering PerimeterX (PX) SDK collector traffic to generate valid _px3 or _px2 cookies. Without this skill, developers must manually deobfuscate SDK code, locate cryptographic constants, decode binary OB responses, and reconstruct 200+ field payloads across multiple deployment tiers, often spending 6-12 hours per new site with no guarantee the generated cookie will pass backend trust validation.

Core Features & Use Cases

• End-to-End PX Cookie Generation: From CDP capture to a working _px3/_px2 generator, covering all 4 validated sites (iFood, Grubhub, Total Wine, Academy) across lenient, strict, and strict+ tiers.
• Algorithm Reconstruction: Includes 9 bundled Node.js algorithm modules (payload XOR, HMAC-MD5 PC, OB decode, SID steganography, UUID v1, djb2 hash, memory synthesis, anti-tamper, /ns fetch) that have remained stable for 3 years.
• Cross-Version SDK Analysis: Provides grep-pattern-based location methods, a 27-entry OB handler shape-matching table, and 23 real-world gotchas to handle SDK upgrades without rewriting generators.
• Strict-Tier Validation: Includes field-by-field diff tools, cross-event consistency checkers, counter synchronization validators, and a 4-way trust matrix to localize whether failures are due to cookie content or transport/IP issues.

Quick Start

Use the px-reverse skill to reverse-engineer a new PX-protected site by providing the target URL and capturing 6 batches of collector traffic via CDP, then run the bundled decode and diff scripts to build a working cookie generator.