FST Pay ensures safe teen payments with strict real-time checks

FST Pay: Deterministic Safety-Gated Architecture for Youth Digital Payments

Software EngineeringCryptography and Security

Summary

Digital payment systems now let teens access money instantly, which helps them learn about finances but also risks impulsive buys and scams. The authors present FST Pay, a system that ensures teen payments follow strict, clear rules before approval. It blocks or flags risky transactions using six fixed safety checks, involving spending limits, guardian approval, timing, and device security. AI is only used afterward to explain transactions, not to influence payment decisions.

What this means in practice

  • For digital payment providers: Implement a safe teen payment system by enforcing strict deterministic checks and guardian approvals to reduce fraud and impulsive spending.$Commercial implications: Enables payment platforms to offer youth accounts with built-in safety features that comply with financial regulations.
  • For financial fraud prevention teams: Use deterministic gating on transactions to detect and block high-risk teen spending without relying on unpredictable AI models.

Authors

Shaikh Mohammed Burhan, Syed Farhaan Quadri, Tabassum Nahid Sultana

Abstract

Digital payment infrastructures increasingly provide adolescent users with direct access to real-time financial services. While early access promotes financial literacy and digital inclusion, it exposes young users to severe risks of impulsive spending, social engineering frauds, unauthorized transactions, and merchant exploitation. Conventional countermeasures rely on probabilistic machine learning or rigid static controls. However, allowing probabilistic or generative artificial intelligence (AI) models to directly influence real-time payment authorization introduces non-determinism, unpredictable edge-case behavior, and critical audit vulnerabilities. This paper introduces Financial Safety for Teens Pay (FST Pay) as an architectural and formal specification. FST Pay is founded on an immutable operational boundary: strict deterministic safety gating on the real-time authorization path coupled with decoupled downstream AI explanation. Transactions initiated via rails like UPI are subjected to six deterministic invariant checks covering spending limits, guardian co-sign policies, transaction amount thresholds, merchant category codes, temporal access intervals, and hardware integrity constraints. Transactions are classified strictly into ALLOW, REVIEW, or BLOCK outcomes through an ordered, mutually exclusive decision function. High-risk transactions trigger an asynchronous guardian co-sign workflow. Generative AI is relegated entirely downstream of settlement, consuming published post-decision events solely to generate natural-language financial insights without holding mutation privileges over the ledger.