architecture/diode-standard — PointSav Documentation

An attacker who breaches one machine rarely wants that machine. They want the next one. Lateral movement — pivoting from a first compromised node to more valuable nodes — is the dominant pattern in modern breach reports [^2].

The Diode Standard removes the pivot. In electrical engineering a diode conducts current one way and blocks the other; the Diode Standard applies the same rule to commands across the PointSav operating-system family — traffic flows from authority to subject, and never the reverse [^1].

A Subject operating system has no code to initiate an authority relationship: no shell client, no peer-to-peer routing table. Upstream control is not blocked by a firewall rule — the code to express it does not exist on the Subject.

For a regulated buyer the consequence is concrete. An entire breach category is removed by structure, and a complex fleet stays auditable because every connection obeys one uniform rule. This article covers the authority hierarchy, the three traffic categories, the structural removal of lateral movement, and the adapter that enforces the standard.

[edit]The hierarchy

The Diode is the foundational topology of the whole operating-system family — not a feature of one operating system, but the law governing how all of them communicate.

Position	Operating system	Privilege
Authority	[[console-os	`os-console`]] and [[os-orchestration
Subject	[[totebox-os	`os-totebox`]], [[mediakit-os

A Totebox cannot command a MediaKit; a MediaKit cannot reach into a Totebox. A compromised Subject cannot move laterally to another Subject, because the protocol stack contains no routing logic to do so.

[edit]The three traffic categories

Traffic	Direction	Status
Downstream control	Authority → Subject	Permitted: configuration, content, commands, updates
Upstream telemetry	Subject → Authority	Permitted but strictly sanitised: logs, heartbeats, status
Upstream control	Subject → Authority	Structurally blocked: no shell access, no RPC, no admin requests

Upstream control is blocked because the Subject is structurally incapable of initiating an authority relationship. The absence is the control.

[edit]Why this matters

Lateral movement — an attacker compromising one node and using it to reach more valuable nodes — is the dominant pattern in modern breach reports [^2]. The Diode Standard removes it structurally.

Scenario	Without the Diode	With the Diode
A plugin on `os-mediakit` is compromised	The attacker rides the management tunnel back to the corporate `os-totebox`	The adapter has no upstream route; the attacker is contained on the public-facing host
A Totebox kiosk is physically compromised	The attacker scans the local network and pivots to the MediaKit	The kiosk Totebox cannot route to other Subjects; it is a dead end
`os-orchestration` is compromised	The attacker holds the keys to every Totebox in the fleet	`os-orchestration` holds no Totebox keys; it requests signed capabilities per query, so a full Orchestration compromise yields no Totebox decryption material

[edit]The adapter

The Diode is enforced by a small, hot-pluggable service, `service-pointsav-link` (the pointsav-protocol package). It is the only code that translates authority commands into Subject-executable operations.

Property	Behaviour
Default state	Not installed; the Subject has no concept of phoning home
Activated state	Hot-plugged by the operator with a single command; brings the Subject under fleet management
Failure mode	If the adapter crashes, the link severs cleanly; the Subject keeps running standalone; the fleet-management surface goes dark
Code path	Diode policy lives inside the adapter, not the OS kernel — the policy can be updated without touching the rest of the system

[edit]The universal standard

The Diode is not a MediaKit feature or a Totebox feature; it applies identically to every os-* operating system. The same `service-pointsav-link` package, with different policy bindings, sits between any pair of nodes that communicate.

This single uniform standard is why a complex fleet stays auditable: every connection looks the same and obeys the same rules.

[edit]See also

os-family-overview — the eight operating systems the Diode topology governs
machine-based-auth — the machine-based authorization system the Diode works alongside
deployment-patterns — the fleet deployment patterns that apply the Diode discipline