PGTAIL: Pre-Transaction Risk Evaluation for Digital Asset Protection
Policy-Governed, Audit-Native, Fail-Closed
Version 1.0 — May 2026
Abstract
This paper introduces the PGTAIL engine: a pre-transaction risk evaluation API that evaluates every proposed blockchain transaction against user-defined policy before funds move. Unlike traditional security tools that respond after a loss, PGTAIL operates in the only window where the outcome can still be changed — before settlement.
The production engine evaluates transactions against 60+ behavioral, registry, and pattern-based threat guards, returning a structured decision — allow, warn, hold, or block — with a full audit log. Policy is fully configurable: five named postures from Standard to Zero-Trust, or a fully custom profile with per-guard control. The architecture is fail-closed: ambiguity defaults to protection, not convenience.
The long-term vision extends this enforcement to the protocol layer — a security-first Layer 2 where every transaction is evaluated at the sequencer level by default. That vision is the roadmap. This document describes what is built and working today.
1. Introduction: The Systemic Failure
The rise of digital assets has outpaced the development of equivalent trust, control, and fraud mitigation mechanisms. The current ecosystem forces users into an impossible choice:
- Custodial Platforms (e.g., Exchanges): These offer convenience but expose users to catastrophic insider threats, operational errors, and a complete loss of sovereignty. As recent events have shown, users are not in control.
- Self-Custody (e.g., Cold Wallets):These offer strong key custody but lack behavioral intelligence and policy enforcement. They are secure but “dumb,” offering no protection from sophisticated phishing, social engineering, or simple user error.
The gap is not in key management. The gap is in pre-transaction policy enforcement — the ability to evaluate a proposed action against your own rules before it becomes irreversible. PGTAIL closes that gap at the API layer, available today, without requiring users to change how they hold their keys.
2. The PGTAIL Engine: What Is Built Today
PGTAIL is a pre-transaction risk evaluation API. Before a transaction leaves a wallet or application, it is submitted to the engine for evaluation. The engine checks the proposed action against the user's active policy and returns a structured decision. The calling application acts on that decision before signing.
This is comparable in architecture to Stripe Radar — a risk API that sits in front of payments — but purpose-built for blockchain transactions, with policy fully in the user's hands rather than the platform's.
60+ Active Threat Guards
Behavioral detection, registry enforcement, approval control, wallet fingerprinting, network health, and transaction anomaly guards — evaluated before signing.
Policy Configurator
Five named postures from Standard to Zero-Trust, or a fully custom profile with per-guard control and threshold tuning. Policy deploys to the engine immediately.
Structured Decisions — Fail-Closed
Every evaluation returns allow, warn, hold, or block. Blocks occur only when policy explicitly demands them. Ambiguity defaults to protection, not convenience.
Forensic-Ready Audit Log
Every decision is logged with full context: which guards fired, what scores were assigned, what the policy state was at evaluation time. Signed, timestamped, reviewable.
Guard Coverage (60+ active guards across 9 categories)
- Registry enforcement: blacklist, graylist, whitelist matching
- Trust range: sovereign cap, risk floor, block threshold
- Behavioral — dusting: ceiling, mature wallet threshold
- Behavioral — peeling chain: spread, timing, bot-like patterns
- Wallet & signature: address poisoning, EIP-712/Permit guard
- Token & asset: honeypot detection, airdrop block, stolen asset tagging
- Allowance & approval: firewall, simulation, drain detection
- Network & protocol: sanctions screening, bridge health, DeFi risk
- Transaction behavior: velocity, composite signal, wash sale awareness
3. Background and Motivation
The inception of this protocol is rooted in firsthand experience. Its creator, Richard Balia, is a cybersecurity leadership official with 30 years of technical experience, including over 15 years leading cyber and information assurance efforts across the U.S. Department of Defense and commercial tech firms.
In early 2025, Richard became a victim of a major Coinbase security breach that exposed critical failures in user account protection. This proved a definitive truth: in any architecture where policy enforcement is separate from the asset itself, users are not in control.
The response was not to build another wallet or another custodian. The response was to build the enforcement layer that sits in front of every transaction — configurable by the user, auditable by design, and fail-closed by default. The PGTAIL engine is that layer.
4. Roadmap
The prevention engine is the foundation. Each phase extends the reach and depth of that enforcement.
Policy Engine + Dashboard — Complete
PGTAIL pre-transaction evaluation API with 60+ guards, five named postures, policy configurator dashboard, and fail-closed architecture. Production-deployed on AWS.
Forensics Production — Active
Structured case intake, transaction graph analysis, pattern extraction, and evidence packaging for law enforcement, insurance, and compliance teams. Every investigated case feeds back into prevention policy.
Institutional API — Planned
Enterprise SDK and SLA-backed integration for exchanges and custody providers. The same PGTAIL engine at institutional transaction volume, with batch evaluation and compliance report generation.
Protocol-Native Enforcement — Vision
On-chain smart account contracts enforce policy at the transaction execution layer. Sequencer-level integration embeds PGTAIL as a mandatory pre-execution hook — every transaction on the network is evaluated by default, without requiring API integration by the application.