Sentinel

Token-2022 Native
Transfer Hook Protocol

Programmable Compliance for Token-2022 Assets

Sentinel is a Token-2022 transfer hook protocol that enforces programmable compliance policies directly at transfer execution. No backend queues. No centralized enforcement.

Compliance Execution Flow

Transfer Request
Initiator wallet
Token-2022 Transfer Hook
Program invocation
Sentinel Compliance Engine
RuleSet PDA + ComplianceRecord PDA
Rule Evaluation
9 composable policy primitives
ALLOW
REJECT
Built on SolanaToken-2022 NativeTransfer Hook PoweredAnchor FrameworkPrivacy-OrientedFully On-Chain

The Problem

Compliance Should Live Inside The Asset

Most compliance systems rely on off-chain monitoring, centralized approval workflows, and fragmented enforcement layers — creating manual reviews, regulatory fragmentation, and centralized trust assumptions.

Traditional Model

Transfer
External Compliance Service
Manual Enforcement
Settlement

Sentinel

Transfer
Token-2022 Hook
On-Chain Rule Engine
Settlement

Capabilities

Protocol-Native Compliance

On-Chain Rule Engine

Composable compliance policies evaluated atomically during transfer execution, with no external dependencies.

Jurisdiction Controls

Restrict transfers based on regulatory regions using bitmask-based policy enforcement over wallet compliance records.

KYC Attestations

Attach compliance records directly to wallets through on-chain attestations with configurable expiry windows.

Velocity Monitoring

Enforce rolling-window transfer volume limits with automatic resets — no backend required.

Transfer Controls

Minimum transfers, maximum transfers, cooldown periods, and time-restricted transfer windows.

Privacy-Ready Architecture

Designed for future zero-knowledge attestations without exposing identity data on-chain.

Architecture

Protocol Architecture

Wallet
Initiator
Transfer Request
Token-2022 Transfer
Sentinel Transfer Hook
Program CPI
RuleSet PDA
Policies
ComplianceRecord PDA
Wallet state
Compliance Evaluator
On-chain logic
ALLOW
REJECT

Rule Primitives

9 Composable Compliance Policies

Velocity Limit

Rolling-window volume controls that reset automatically based on time intervals.

Volume: 2,000 / 5,000 — PASS
KYC TTL

Require valid compliance within configurable expiry windows attached to wallet records.

Expires in 215 days — PASS
Jurisdiction Block

Region-based transfer restrictions using bitmask encoding over compliance records.

Jurisdiction: OFAC — FAIL
Allowlist

Restrict transfers to a pre-approved set of wallet addresses.

Wallet in allowlist — PASS
Sanctions Blocklist

Block known prohibited addresses from executing transfers.

Wallet on blocklist — FAIL
Maximum Transfer

Enforce per-transfer ceiling amounts to prevent large single transactions.

500 ≤ 1,000 ceiling — PASS
Cooldown Period

Require mandatory waiting periods between successive transfers.

Last transfer: 2h ago — PASS
Transfer Window Lock

Restrict transfers to approved UTC time windows only.

Hour 21 outside 9–17 — FAIL
Minimum Transfer

Enforce transaction floors to prevent dust and micro-transaction spam.

Amount ≥ floor — PASS

Technical Design

Designed for Real Compliance Workflows

Sentinel separates attestation from enforcement. A compliance provider calls attest_wallet to create or update an on-chain compliance record storing jurisdiction bitmask, KYC expiry, and compliance metadata.

During transfer execution, the Token-2022 hook loads the wallet's record and evaluates the active ruleset atomically. No backend approvals. No off-chain monitoring. No identity information leaves the chain.

9
Rule Types
Atomic
Enforcement
Token-2022
Native
On-Chain
Fully

Test Coverage

9 compliance rule primitives
PDA-based ruleset architecture
Atomic transfer enforcement
LiteSVM unit test coverage
Token-2022 transfer_checked CPI
Independent rule evaluation tests

Interactive Demo

See the Compliance Engine in Action

Live Compliance Simulation

Transfer Parameters

500 tokens

Rule Evaluation Trace

KYC TTLPASS
JurisdictionPASS
Velocity LimitPASS
Maximum TransferPASS
✓ TRANSFER ALLOWED

Use Cases

Built for Real Deployments

AI Agent Wallets

Per-agent spending limits, transfer windows, and policy enforcement for autonomous agent systems.

Real World Assets

Investor accreditation and jurisdiction restrictions for tokenized real-world assets.

DAO Treasury & Payroll

Transfer limits and compliance enforcement for contributor payments and treasury operations.

Institutional Stablecoins

Programmable transfer controls built directly into the asset at issuance.

Roadmap

What's Next

Phase 1

Programmable Compliance Engine

Completed

Phase 2

Token-2022 Ecosystem Integration

In Progress

Phase 3

Zero-Knowledge Compliance Proofs

Planned

Phase 4

AI Compliance Agents

Research

Protocol Native

Compliance enforced directly at transfer execution. No monitoring layer. No approval queues. No backend.

Composable

Works with any Token-2022 asset without requiring custom implementations. Drop-in compliance infrastructure.

Privacy-Oriented

Designed for future zero-knowledge attestations and privacy-preserving compliance proofs.

Build Compliant Assets Without Sacrificing Composability

Sentinel brings programmable compliance directly into Solana token execution — atomic, on-chain, and fully composable.