Principles

Eight letters, each one a requirement

The name is a backronym over the properties the standard makes normative. They exist to distinguish a trust infrastructure for persistent artifacts from infrastructures designed for server-identity authentication.

Letter	Property	What the standard requires
S	Sealed	Every trusted artifact is cryptographically sealed: independent co-signatures cover the same canonical payload, one per trust dimension — data, person, time, location, environment, and others defined by the scheme. Convergence of independent attestations, not single-signer authority, establishes trustworthiness.
I	Interoperable	The framework is scheme-independent. One verification pipeline and one coverage-report format serve many application schemes; scheme-specific rules enter through published registries and deployment profiles rather than forked technology.
G	Graduated	Trustworthiness is graduated, not binary. The verifier produces an objective coverage report of hard and soft check results; the scheme’s classification policy maps it to a classification label; the verifier’s acceptance policy turns the label into a decision.
N	Non-repudiable	Issuance is attributable and undeniable. Authority is exercised by threshold quorum and by federated trust authorities spanning organizational boundaries — never by an unaccountable single key — and inclusion in publicly auditable transparency logs provides third-party evidence of what was issued.
A	Anchored	Signing authority flows through a delegation hierarchy with the authorization scope narrowing monotonically at every link, and every verification path terminates at a root anchor in the trust anchor bundle. Verification requires no phone-home to the issuer and no proprietary component.
T	Trust	The domain of the framework is trust: the establishment, assessment, and withdrawal of confidence in signed artifacts. Trust is graduated, and it is a lifecycle — granted authority can be withdrawn through threshold-gated revocation that propagates to every transitively bound artifact.
I	Infrastructure	Signatif operates at the infrastructure level — shared anchors, logs, and registries independent of any single application — beneath any product that needs verifiable artifacts.
F	Framework	Not a product or protocol. Requirements that independent implementations conform to, and that domain-specific profiles instantiate — with conformance classes that make "conforming" testable.

Where the letters come from

Beneath the eight letters, the standard groups its design themes — each theme backing at least one requirements class.

Authority and delegation

Cryptographic scope enforcement — scope is a signed field checked at every link, not an external policy document
Threshold signing at every level — no single point of cryptographic compromise anywhere in the graph
Federated trust authorities — threshold groups of independent organizations sharing one aggregate key
Topology flexibility — hierarchical, federated, cross-recognized, and mesh profiles as first-class citizens

Multi-party attestation

Multi-party co-signed artifacts — several signers attest the same canonical payload
Multi-dimensional reality attestation — time, location, and environment as cryptographic dimensions, not metadata
Cross-domain trust fusion — co-signatures from independent roots carried on one artifact

Scope and binding

Live scope conditions — executable predicates evaluated at verification time against content and context
Revocation propagation — revoking authority state invalidates every transitively bound artifact, across all dimensions and chains
Challenge-response authenticity — nonce-bound fresh artifacts prove a live key, defeating replay of static copies

Transparency and time

Mandatory transparency — inclusion in a recognized log is a verification requirement, not a courtesy
Multi-log attestation — M-of-K independent logs, so no single operator controls the record
External time anchoring — signing time established by independent time sources, never the signer’s clock alone

Trust assessment

Graduated trust — labels reflect the depth and breadth of dimensional coverage, not just primary-signature validity
Risk-based acceptance — verifiers apply their own policy to the label for each decision context
Deterministic reporting — identical verifier state yields identical coverage reports

Not a criticism of PKI

These principles address the persistent-artifact trust problem specifically. PKI remains the appropriate, mature technology for TLS, code signing under active policy enforcement, and identity binding — and PKI-like deployments are one configuration of the Signatif framework, not a rejected alternative.