From July 3 through July 21 of 2017, ConsenSys Diligence conducted a security audit of the 0xProject's contract system. The findings and recommendations are presented here in this report. The 0x team on July 28 presented an updated system for ConsenSys Diligence to review. On August 3, a final system was presented and this report includes the resolutions and is published on August 4.

Disclaimer: This entire report is a DRAFT. As much as possible, we've clearly indicated in the heading which sections might are expected to change.

Contents:

• 1. Summary of the Review process and scope
• 2. Description of the 0x contract system functions
• 3. General Findings
• 4. Specific Findings
• 5. Test Coverage Analysis
• 6. Appendix