# 4SI

> 4SI develops physical trust infrastructure that helps digital systems verify the human, object or physical authority behind consequential decisions. 4SI is a brand of For Safety Group Inc., headquartered in Phoenix, Arizona.

4SI addresses a specific trust gap: digital systems can secure and process information, but information alone does not always establish whether the expected person or physical object is actually present. Presence is the 4SI platform connecting physically grounded verification to existing identity, policy, transaction and operational systems. Protected mechanisms and sensitive implementation details are intentionally not published.

## Start here

- [Homepage](https://www.by4si.com/): The institutional thesis and a plain-language explanation of what 4SI does.
- [Presence](https://www.by4si.com/presence): The 4SI physical trust platform comprising Presence Key, Presence Layer and Presence Home.
- [Applications](https://www.by4si.com/applications): Human authorization, product authenticity, critical infrastructure, AI-agent authorization, finance, defense and other deployment domains.
- [4SI Intelligence](https://www.by4si.com/intelligence): Evidence, risk indexing and decision support for physical trust deployment.
- [Presence Risk Index](https://www.by4si.com/intelligence/presence-risk-index): A versioned 0–100 editorial research position across human, agentic, object and infrastructure Presence Risk; not a probability or prevalence estimate.
- [Presence Exposure Radar](https://www.by4si.com/intelligence/exposure-radar): Five reviewed systemic Exposure clusters showing where trust is breaking, which action is at risk and which physical trust boundary is missing.
- [Evidence Explorer](https://www.by4si.com/intelligence/incidents): A current filterable snapshot of 4,527 source-backed records, including 4,512 official records, 15 extended validations and transparent A–D Evidence Assurance.
- [State of Presence Risk 2026](https://www.by4si.com/intelligence/reports/presence-12-month-review): The public launch report, including ten curated Flagship Cases and explicit data limitations.
- [Intelligence Methodology](https://www.by4si.com/intelligence/methodology): Evidence tiers, scoring, confidence and Economic Consequence Range boundaries.
- [Legal Center](https://www.by4si.com/legal): Research disclaimers, regional privacy notices, source standards, corrections and AI/editorial transparency.
- [Approach](https://www.by4si.com/approach): Evaluation principles, threat models, boundaries and integration logic.
- [Founding Institution Program](https://www.by4si.com/founding-institutions): A structured pathway for qualified organizations to map, evaluate and pilot one consequential physical trust boundary with 4SI.

## Presence products

- [Presence Key](https://www.by4si.com/presence/key): Physical human-presence and authority verification at consequential decision boundaries.
- [Presence Layer](https://www.by4si.com/presence/layer): Physical product, component, document and asset authenticity verification.
- [Presence Home](https://www.by4si.com/presence/home): The institutional environment for trust relationships, policy, lifecycle, evidence and controlled integrations.
- [CL Technology](https://www.by4si.com/presence#cl-technology): 4SI's proprietary verification technology. Public descriptions cover its purpose and outputs, not its confidential implementation.

## Research and explanations

- [Verification as a Control Primitive for Frontier AI](https://www.by4si.com/verification-control-primitive): 4SI's research argument for physically grounded authority at consequential AI execution boundaries.
- [Economic Research](https://www.by4si.com/economic-research): Research on the economic exposure created by weak links between digital records and physical reality.
- [Papers](https://www.by4si.com/papers): 4SI research index.
- [FAQ](https://www.by4si.com/faq): Direct answers about the platform, integration, privacy, post-quantum positioning and public disclosure boundaries.
- [Glossary](https://www.by4si.com/glossary): Canonical definitions for physical trust, reality verification, authority, physical anchors and verification results.

## Company and contact

- [Company](https://www.by4si.com/company): Company origin, founder and strategic direction.
- [Founding Institution Program](https://www.by4si.com/founding-institutions): Institutional design partnerships beginning with one real authority, authenticity or custody workflow.
- [Contact](https://www.by4si.com/contact): Business and institutional inquiries.
- Email: contact@by4si.com

## Canonical identity

- Brand: 4SI
- Legal entity: For Safety Group Inc.
- Category: Physical trust infrastructure
- Website: https://www.by4si.com/
- Slogan: Trust must survive intelligence.
- Primary language: English

## More detail

- [Full AI-readable company and Presence summary](https://www.by4si.com/llms-full.txt)