feat: Layer 3 KYC/OFAC attribute proof demo — BBS+ selective disclosure via extensions.lemma Header

[aggre]

Concept Demo: x402 Layer 3 — KYC/OFAC Attribute Proof

Demonstrates the "Third Layer" on top of x402 + AgentCore Payments:
BBS+ selective disclosure of KYC/OFAC attributes via extensions.lemma Header.

Architecture

This implements the 3-layer architecture described in the PPSI stablecoin blog article:

• Layer 1: x402 HTTP payment protocol (signature verification)
• Layer 2: AgentCore Payments (spending limits, audit trail, wallet integration)
• Layer 3: Lemma ZK attribute proof (KYC/CDD/OFAC/sanctions — this demo)

What's Included

• 6-phase agent demo with typewrite CLI effects showing the full KYC verification flow
• 3 KYC profiles: basic, amlCompliance (PPSI/MiCA), institutional
• BBS+ selective disclosure matrix: 4 of 8 attributes revealed, PII never transmitted
• Self-contained implementation: works with only main-branch dependencies
• 15 tests: profile→gate mapping, PPSI/MiCA compliance attributes, header construction

Usage

pnpm layer3                # Basic KYC verification
pnpm layer3:aml            # Full AML/KYC with OFAC sanctions
pnpm layer3:disclosure     # With BBS+ selective disclosure visualization

Regulatory Scope

• PPSI NPRM (US): CDD, AML/CFT, OFAC sanctions screening, beneficial ownership
• MiCA (EU): KYC, AML, cross-border notification
• Wallet-invariant: Coinbase CDP ✓ | Stripe Privy ✓