Strict Baseline Class

NAP-CLASS-1

Strict Baseline Class

draft

NAP ID: NAP-CLASS-1 Parent: NAP-CLASS Class number: 1

Description

NAP-CLASS-1 is the strict baseline posture for napplets that do not declare any class-contributing NAP capabilities. Shells emit a restrictive Content Security Policy with connect-src 'none', show no consent prompt, and send class.assigned with class: 1. This is the default class for any napplet whose manifest lacks tags from NAPs that would promote it to a higher class.

CSP Posture

connect-src 'none'

Shells emitting the NAP-CLASS-1 posture MUST include connect-src 'none' in the runtime CSP served with the napplet's HTML. The directive is the signal that the napplet has no user-approved direct-network origins. Other directives in the baseline CSP (e.g., script-src, default-src, img-src) are shell-policy concerns and are NOT specified by NAP-CLASS-1 — only the connect-src value is the class's defining characteristic.

Manifest Prerequisites

NAP-CLASS-1 is the default posture. A napplet manifest reaches NAP-CLASS-1 when no other class-contributing NAP's trigger conditions are met. Future NAP-CLASS-$N entries (with $N > 1) MUST document their own trigger conditions; absence of all such triggers means the napplet is NAP-CLASS-1.

There is no consent state associated with NAP-CLASS-1 and therefore no user-consent prerequisite. A napplet resolves to this class at first load, at every subsequent load, and under every shell that implements the base protocol — independent of user action.

Shell Responsibilities

• Shell MUST emit a runtime CSP header containing connect-src 'none' for the napplet's HTML response.
• Shell MUST NOT prompt the user for any network-access consent when serving a NAP-CLASS-1 napplet — there is nothing to consent to, and raising a prompt would mislead the user into believing a choice is available when none is.
• Shell MUST send exactly one class.assigned envelope with payload { class: 1 } at iframe-ready time per NAP-CLASS's wire-timing rules. A shell that implements nap:class MUST deliver the envelope even when the value is 1; silence is not the same signal as explicit assignment.
• Shell SHOULD treat residual <meta http-equiv="Content-Security-Policy"> in NAP-CLASS-1 napplet HTML as harmless (CSP intersection of two connect-src 'none' values is still 'none'), but MAY log a deployment warning to encourage napplet authors to migrate away from meta-CSP emission. Shells MUST NOT refuse-to-serve a NAP-CLASS-1 napplet solely on the basis of residual meta-CSP.
• Shell MUST NOT add sandbox relaxations or CSP directives that would cause a NAP-CLASS-1 napplet to behave distinguishably from another NAP-CLASS-1 napplet. The posture is uniform across all napplets in this class.

Security Considerations

Strictness floor, not a ceiling

NAP-CLASS-1 is the minimum-trust posture. It is appropriate for napplets with no network requirements, napplets that rely exclusively on shell-mediated resource fetching (via other NAPs that provide proxied resource access), or napplets in development/test environments where network egress is disabled by policy. A shell that wishes to apply a weaker posture than NAP-CLASS-1 cannot do so while claiming conformance to this class — the connect-src 'none' directive is not a default, it is a guarantee. A weaker posture is a different class and MUST be assigned a different integer.

CSP intersection

Because the browser enforces CSP as an intersection of header and meta directives, a NAP-CLASS-1 napplet that accidentally ships meta-CSP with connect-src 'none' will still behave correctly — the intersection of 'none' and 'none' is 'none'. This is why shells treat residual meta-CSP as harmless in the NAP-CLASS-1 case but refuse-to-serve in higher classes: a meta-CSP with connect-src 'none' silently suppresses any header-level grant, which is catastrophic for classes that rely on granted origins but a no-op here.

No grant state

NAP-CLASS-1 has no persistent state — no consent decision, no origin list, no (dTag, aggregateHash) key. Every napplet resolving to NAP-CLASS-1 is indistinguishable from every other at the class level. This makes the class a safe default: a shell may assign it silently, without interrupting the user, without persisting any record that would outlive the session.

Compatibility with other NAPs

NAP-CLASS-1 is deliberately compatible with every other NAP a shell may choose to implement. A shell may grant a NAP-CLASS-1 napplet access to, for example, a shell-mediated storage NAP or a shell-mediated relay NAP; the class does not forbid this. What the class forbids is the napplet reaching external network origins directly from the frame — everything network-sourced MUST flow through a shell-mediated NAP's postMessage surface.

References

• NAP-CLASS.md — parent spec; defines the class.assigned envelope, the window.napplet.class runtime surface, and the authoring rules for track members including NAP-CLASS-1.
• NIP-5D — Napplet wire format.

Changelog

• 71ad6a1 - Introduced NAP-CLASS-1 as the strict baseline posture sub-track.