FERZ is not Runtime Application Security
This comparison addresses an adjacent category that shares the runtime property with FERZ: both architectures operate at runtime and can prevent execution. The distinguishing FERZ property is that the runtime decision is an authorization verdict evaluated against encoded policy and governed state, not an attack-detection verdict evaluated against threat signatures or behavioral baselines. The architectural-class test is established in The Authorization Artifact Test (Meyman, 2026; DOI 10.5281/zenodo.20013582) and the category-separation framework in A Taxonomy of AI Governance Approaches (Meyman, 2026; DOI 10.5281/zenodo.18275969), which frames Visibility, Alignment, and Authorization as the three governance problems. Runtime Application Security addresses defensive security, a separate concern.
Where the categories diverge
The two architectures diverge along four architectural axes.
At the AI action proposal boundary. The authorization verdict precedes execution of the proposed action, with built-in action canonicalization and AI-action semantics.
At the request-handling or function-invocation boundary inside the instrumented application runtime. Inspects activity as it flows through hooks placed in the application.
Encoded policy evaluated against a canonicalized action specification, governed state, and policy version. The question asked is whether the action is authorized.
Pattern matching against attack signatures, behavioral analytics, or vulnerability fingerprints. The question asked is whether the action looks like an attack.
A verdict in the canonical verdict space {ALLOW, DENY, ABSTAIN} with a authorization artifact reconstructable from policy, action specification, and governed state.
An attack-detection record, block log, or alert. The artifact states what attack pattern was detected and what defensive response was taken.
Fail-closed by architectural design. Execution is blocked when governance conditions are not met.
Configurable. Products typically offer monitor-only, alert-only, or block-on-detection modes. Default behavior varies by product and deployment.
Why the distinction is structural
The two architectures ask categorically different questions even when both operate at runtime and both can prevent execution. Runtime Application Security asks whether an action is an attack: does this request match a known attack signature, does this function call deviate from baseline behavior, does this payload contain a vulnerability fingerprint. FERZ asks whether an action is authorized: does this proposed AI action, evaluated against encoded policy and governed state, fall within what governing policy permits. Attack-detection and policy-based authorization are different decision problems, and improvements in attack-detection do not produce authorization properties.
The authority sources do not substitute for each other. Attack signatures generalize across applications because attack patterns are well-studied: SQL injection, deserialization attacks, prompt injection. Authorization policies are domain-specific to the AI system being governed: which actions are permitted, under which conditions, against which governed state. A RASP system configured with AI-specific signatures detects more AI-specific attacks; it does not begin to evaluate whether a proposed action is permitted by policy. The two authority sources address different concerns and produce different evidence artifacts.
The evidence artifacts reflect this difference. A Runtime Application Security record states what attack pattern was detected and what defensive action was taken: "request matched SQL injection signature SI-042 and was blocked." A FERZ verdict states what was authorized: "policy version P-17 evaluated against canonicalized action A-921 in governed state G-558 and emitted verdict ABSTAIN." The first is an attack-detection log; the second is a policy-versioned authorization artifact. Both can be useful; they are not interchangeable, and a more sophisticated attack-detection log does not become an authorization artifact.
The structural claim follows. Runtime Application Security and FERZ compose well: Runtime Application Security can protect the FERZ control plane from attacks; FERZ can govern AI actions within an application that Runtime Application Security also protects. But applying Runtime Application Security to AI systems does not produce AI-action authorization. The architectural class remains security and attack-detection regardless of what is being protected. Calling a Runtime Application Security capability "AI governance" in the authorization sense is a category error.
What buyers often confuse
The most common conflations involve security-class systems repositioned as AI governance under runtime framing. The architectural argument applies regardless of presentation.
Architectural diagnostic
Any vendor or product claiming AI governance can be evaluated against four architectural questions, anchored to The Authorization Artifact Test (Meyman, 2026; DOI 10.5281/zenodo.20013582):
Does the system produce an artifact for the proposed AI action that exists before the action executes?
Is the authorization artifact reproducible from policy, canonicalized action specification, and governed state, sufficient for independent third-party verification?
Does the system include an ABSTAIN verdict with explicit fail-closed semantics pending authorized human override?
Is fail-closed the architectural default, or an opt-in configuration?
References
Related doctrine and concepts
Frequently asked questions
A RASP product configured with AI-specific signatures detects AI-specific attacks. The decision basis remains attack-pattern matching. AI-action authorization requires evaluating proposed actions against encoded policy and governed state, not against attack signatures. The two decision problems are categorically different and do not substitute for each other.
A WAF inspects HTTP traffic for attack patterns at the network boundary. It operates one layer earlier than the AI runtime and does not see the proposed AI action specification. WAFs are useful defensive infrastructure; they do not constitute AI-action authorization.
They compose. RASP protects the runtime from attacks; FERZ authorizes AI actions against policy. RASP can defend the FERZ control plane itself; FERZ can govern AI actions within an application that RASP also protects. The two address different concerns and are layered, not substitutable.
Three properties: the authority source (encoded policy and canonicalized action specification versus attack signatures), the evidence artifact (authorization verdict with policy-versioned evidence versus attack-detection record), and the default execution behavior (fail-closed by architectural design versus configurable, often fail-passive in monitor-only deployments).
"AI security" is accurate; RASP is a security architecture. "AI governance" in the authorization sense is a category error if the underlying capability is attack-detection. Governance in the authorization sense requires policy-based decisions about proposed actions, not signature-based decisions about attack patterns.
FERZ, Inc. (2026). FERZ is not Runtime Application Security. https://ferz.ai/governance/comparisons/ferz-is-not-runtime-application-security
BibTeX
@misc{ferz2026notrasp,
author = {{FERZ, Inc.}},
title = {FERZ is not Runtime Application Security},
year = {2026},
url = {https://ferz.ai/governance/comparisons/ferz-is-not-runtime-application-security},
note = {FERZ Architectural Comparison}
}