Stage286: QSP Internal Connection as a Product Specification

Overview

Stage286 upgrades the QSP-to-VEP connection from an implementation detail into a product specification.

This stage defines a stable internal contract for how QSP:

• receives normalized input
• produces a decision
• enforces fail-closed behavior
• exports a public-facing exposure contract for VEP

This transforms:

• a connected system

into:

• a reproducible product interface

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Why This Stage Matters

Previous stages established:

• evidence generation
• trust measurement
• QSP–VEP connectivity

Stage286 makes that connection:

• stable
• replaceable
• product-ready

The goal is not a new cryptographic primitive.

The goal is to define a durable internal contract that allows future engines (QKD, PQC, hybrid, etc.) to evolve without breaking the external verification experience.

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Core Product Model

Stage286 defines four product layers:

1. Input Layer

• session_id
• subject
• policy
• evidence (integrity / execution / identity / time)

2. Decision Layer

• decision: accept / pending / reject
• reason
• trust scores
• verified claims

3. Enforcement Layer

• fail-closed behavior (explicit)
• execution state
• allowed outputs

4. Exposure Layer

• public status
• exposure artifacts
• contract SHA-256

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Product Contract

All QSP decisions are normalized into a single deterministic contract:

out/product/qsp_product_contract.json

This contract becomes:

• the source of truth for VEP
• the basis for public verification
• the interface boundary for future systems

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What This Stage Proves

• QSP internal connection can be formalized as a product contract
• fail-closed behavior can be explicitly modeled and verified
• VEP can consume a normalized contract instead of ad hoc artifacts
• system evolution (QKD / PQC / hybrid) is possible without breaking the interface

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Repository Structure

spec/ qsp_product_spec.json

schemas/ qsp_product_contract.schema.json

tools/ build_stage286_product_contract.py verify_stage286_product_contract.py

out/product/ qsp_product_contract.json qsp_product_contract.json.sha256

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Build

python3 tools/build_stage286_product_contract.py
Verify
python3 tools/verify_stage286_product_contract.py
Verification Guarantees

The verification step ensures:

correct stage binding (stage286)
explicit fail-closed requirement
valid decision type
consistency between decision and public status
SHA-256 integrity of the contract
Product Significance

This stage represents a transition:

From:

research pipeline
verification stack
connected prototype

To:

product contract
replaceable architecture
stable verification interface
Conceptual Summary

Stage285:

QSP and VEP are connected

Stage286:

The connection is defined as a product contract

Future Directions
Contract compatibility (versioning / backward support)
Policy negotiation
QKD session binding
PQC signature integration
Threshold/multi-party approval
Remote attested execution
SaaS deployment model
License

MIT License
Copyright (c) 2025