Decoding the Fortza Stack

Why Fortza Uses Deterministic and Non-Deterministic Layers to Detect Fraud Others Miss
Fraud is no longer a binary problem, it’s a behavioral one. And as fraud becomes more adaptive, emotional, and AI-powered, the tools we use to detect it must evolve too.
At Fortza, we use a layered architecture built on two fundamental types of analysis: deterministic and non-deterministic. These aren’t just technical terms, they’re the reason Fortza can detect what other systems miss.
Let’s break it down.
What is a Deterministic Layer?
A deterministic layer is based on fixed, rule-driven logic. If X happens, then Y is triggered. Think of it as a digital tripwire, designed to flag anything that violates a known constraint.
Examples of Deterministic Layers in Fortza:
- Address Validation: If the provided address fails verification against Google’s Address API, the build is blocked or escalated.
- Geolocation Hotspot: If a transaction occurs in a confirmed fraud hotspot, it’s flagged based on past abuse linked to that location.
- Historical Customer Data: If the behavior in this session deviates significantly from the user’s own established history, it's considered a deterministic flag.
Why We Use It:
Deterministic layers are fast, reliable, and built on known truths. They provide immediate certainty, ideal for catching repeat fraud patterns, rule violations, or identity manipulation. But they have limits: they can only catch what’s already been defined.

What is a Non-Deterministic Layer?
Non-deterministic layers use probabilistic models, AI, and behavioral heuristics to make judgment calls. They analyze intent, emotional state, and deviations from expected norms, not just hard-coded violations.
Examples of Non-Deterministic Layers in Fortza:
- Encoder-Decoder AI: Detects subtle deviations in session flow and behavior, things that feel off, even if they don’t break a rule.
- Psychosocial Analysis (e.g., Name Recognition, Moral Drift): Interprets emotional tone, justification language, and social cues that may indicate manipulation or fraud rationalization.
- Anomaly Detection: Flags statistically unusual behavior that doesn’t match user or cohort norms, even if it’s never been seen before.
- FBI Identity Check: Uses partial-match logic to identify potential overlaps with known flagged identities, but lacks biometric or definitive verification, so it’s informative, not fatal.
- Domain Validation: Scores email domains based on age, DNS structure, MX records, and known burner lists, adding contextual risk but not certainty.
- Zip Code Proximity: Raises risk when a transaction occurs near previously reported fraud zones, but correlation doesn’t imply direct intent.
Why We Use It:
Fraud doesn’t always look like fraud, especially in first-party fraud, social engineering, or insider threats. Non-deterministic layers allow Fortza to infer intent, detect emerging fraud tactics, and surface early behavioral indicators.
They give us nuance, adaptability, and early warning, critical tools in a landscape where today’s fraud often mimics normal behavior.
Why This Dual Approach Matters
Here’s the punchline: Fraud isn’t either/or. It’s both/and.
The data shows us that most successful fraudsters today fall into two categories:
- Blatant actors who exploit known technical gaps (deterministic layers catch them fast).
- Sophisticated mimics who operate inside the lines, slowly escalating intent (non-deterministic layers are the only defense).
By using both types of layers, Fortza detects:
- First-time synthetic identities that sneak past traditional KYC.
- Behavioral mimicry, where a fraudster builds a fake profile over time.
- Impersonation patterns, like name overlaps or suspicious email syntax.
- Fraud clusters, where behavioral and geographic signals converge.

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Fortza's Philosophy:
Redundancy Is Resilience
We don’t trust a single signal. We trust the convergence of signals.
That’s why Fortza’s stack doesn’t rely on just a rules engine, or just an AI model. It uses a conversation between deterministic logic, behavioral inference, and psychosocial insight. The result? A fraud signal that’s smarter, faster, and harder to fool.
Non-deterministic layers catch the evolving. They’re intelligent, adaptive, and behavioral.
That’s the real competitive edge.
Why Use Fatal Layers?
Fatal layers are used when the signal is conclusive, not suggestive. These layers are designed to shut down a transaction immediately based on objective evidence—no scoring, no nuance, no further discussion.
Examples of Fortza’s fatal-capable (deterministic) layers include:

Address Validation (Deterministic):
If the Google Address API returns a failed match, the transaction is blocked. The address either exists or it doesn’t—no gray area.
Geolocation Hotspot (Deterministic):
Fires when the transaction’s location matches a confirmed geographic zone tied to previous abuse. These zones are manually flagged based on verified patterns—not predictions.
Historical Customer Data (Deterministic):
Identifies significant deviation from a user's established behavioral baseline. This is a controlled comparison against that user’s own past behavior—not a generalized model—which allows for strict rule-based validation.
These layers are grounded in direct data, not inference. They are black-and-white by design.
Only Deterministic Layers Can Be Fatal
Fortza only allows deterministic layers to be configured as fatal. Why? Because fatal implies final. It implies no further review. That decision must be based on absolute information.
Deterministic layers:
- Operate on fixed logic: If X, then Y.
- Are explainable and repeatable.
- Hold up to legal, audit, and operational scrutiny.
Non-deterministic layers, by contrast, are powerful but probabilistic
- FBI Identity Check (Non-deterministic):
Uses a combination of identity factors like name and gender to surface potential matches, but without fingerprint or biometric verification, there's room for false positives. So it informs risk, but doesn’t decide fate.
- Zip Code Proximity (Non-deterministic):
Flags when a transaction occurs near high-fraud zones, but fraud clusters evolve, and proximity alone doesn’t prove intent. - Domain Validation (Non-deterministic):
Evaluates domain risk based on age, MX record presence, and historical abuse, but some valid domains may still appear risky on paper. - Behavioral & Psychosocial Layers (Non-deterministic):
These read how someone is acting, tone, timing, hesitation, justification, but they require interpretation and trend analysis.
Holistic Fraud Prevention
In fraud prevention, it’s not just about catching the bad, it’s about knowing which bad is undeniable.
Fortza’s fatal layers draw a hard line using deterministic logic.
Because in a world of increasingly human-like fraud, some calls still need to be made by the machine, with zero hesitation.