From Personal Data Server to Personal Metadata Server

Liccium builds the fundamental infrastructure that enables creators and rightsholders to publish machine-readable declarations about their digital works that can be independently verified. The goal is to make information associated with a digital work discoverable and trustworthy without depending on a single platform or service.

A declaration is a machine-readable document signed and published by a creator, rightsholder, custodian, or other declaring party. It contains claims about a digital asset together with a cryptographic signature that allows anyone to verify the origin and integrity of those claims. Those claims may include creator attribution, provenance, rights information, licensing terms, AI training preferences, AI disclosure, identifiers and content fingerprints, certification information, references to related declarations, and other machine-readable metadata associated with the digital asset.

Each declaration references the digital asset using the International Standard Content Code (ISCC, ISO 24138) , a content-derived identifier and fingerprint generated directly from the asset itself. Anyone with access to the asset can independently derive the same ISCC to locate the corresponding declaration, retrieve its metadata, identify the declaring party, and verify that the declaration has not been modified.

At Liccium, we refer to this as content certification: publishing declarations that are cryptographically bound to digital assets, authenticated through trusted digital identities, and independently verifiable.

Different media, the same architecture

AT Protocol gives users control over their identity and data. Every record is published through a Personal Data Server and authenticated by the creator's AT Protocol identity, establishing a verifiable relationship between the identity and the information it publishes.

The architecture closely resembles the way we approach content certification. With Liccium, creators and rightsholders publish signed declarations about digital assets. Both systems rely on cryptographic signatures to establish the origin and integrity of published information, decentralised identities to identify the signer, and creator-controlled infrastructure to make information independently verifiable.

The similarity goes beyond the use of digital signatures. Both systems are built around the same fundamental principle: creators should control how authoritative information about themselves and their work is published.

If creators already use their AT Protocol identity to publish signed records of their posts, why shouldn't they use that same identity to publish declaration metadata describing their digital works?

Publishing declaration metadata

The declaration is the authoritative, signed statement about a digital asset. It is published through a federated declaration infrastructure operated by a publisher, a collective management organisation (CMO), an archive, a federated registry, or another specialised service. These services make declarations available for discovery, resolution, and independent verification.

We propose that the creator's Personal Data Server become an additional, complementary publication channel for declaration metadata. Since the repository is controlled by the declaring party, it becomes the natural place to republish metadata associated with declarations about their digital works. This makes the metadata independently discoverable within the AT Protocol ecosystem while allowing the declaring party to control how it is published.

Applications can discover, index, and interpret this metadata directly through the AT Protocol data graph, alongside any other AT Protocol records. Search engines, archives, rights platforms, AI crawlers, preservation services, and other applications can build their own indexes without depending on a single declaration service or registry.

The declaration itself remains the authoritative, signed statement, published through declaration infrastructure where it can be resolved and independently verified. Republishing its metadata through the creator's Personal Data Server does not replace the declaration; it extends its reach into the AT Protocol ecosystem while giving the declaring party direct control over the publication of metadata describing their digital works.

The Personal Data Server therefore becomes more than a repository for social content. It also becomes a creator-controlled publication point for metadata associated with digital assets. In that sense, it evolves from a Personal Data Server into a Personal Metadata Server.

A common discovery mechanism

If Personal Data Servers become publication points for declaration metadata, applications need a consistent way to discover that metadata.

AT Protocol currently has no standard mechanism for recognising or locating declaration metadata. A post may link to an external resource, but to the protocol it is simply another URL. A client cannot determine whether that resource represents rights information, provenance, licensing terms, AI preferences, or something entirely unrelated. Likewise, there is no common convention for publishing declaration metadata within a creator's repository.

Without a shared discovery mechanism, every application would define its own record structure and lookup process, making interoperability difficult from the outset.

Standard.site is designed to solve exactly this kind of problem. Rather than defining the metadata itself, it defines where structured information is published and how applications discover it.

The same approach can be applied to declaration metadata.

A site.standard.declaration record provides a common location where applications can discover metadata associated with declarations. It deliberately does not define rights vocabularies, provenance models, AI preference formats, trust frameworks, or declaration semantics. Those remain the responsibility of the declaration ecosystems that already define them.

Every application can discover declaration metadata through the same mechanism. Applications that support a particular declaration format can interpret the referenced declaration and present its contents. Applications that do not support that format can still recognise that declaration metadata exists and provide access to the referenced declaration.

Discovery becomes standardised while declaration ecosystems remain independent. Whether declarations originate from Liccium, a publisher, an archive, a collective management organisation, a C2PA manifest, or another future system becomes largely irrelevant. Every application discovers declaration metadata in the same way while remaining free to decide how declarations are resolved, verified, trusted, and presented.

Our proposal

The proposal introduces a Standard.site record named site.standard.declaration that provides a common discovery mechanism for declaration metadata within the AT Protocol ecosystem.

It does not define declaration formats, metadata vocabularies, trust frameworks, or verification procedures. Those remain the responsibility of the declaration ecosystems that define them. The proposal standardises only how declaration metadata is published and discovered through creator repositories.

The proposal is intended as a starting point for discussion. Feedback from the AT Protocol community, developers, and declaration ecosystem providers is welcome to help refine the record and ensure it remains broadly interoperable.

See our proposal on: https://discourse.atprotocol.community/

Proposal: standard.site.declaration

Proposal: standard.site.declaration Draft for Discussion Abstract AT Protocol provides portable identity, portable content, and portable social graphs. What it currently lacks is a standard mechanism for discovering machine-readable declarations associated with digital content. Today, creators and organisations publish declarations about digital assets through websites, registries, the C2PA provenance framework, and other systems. These declarations may describe provenance, copyright ownership...

For more information about Liccium, see liccium.com or docs.liccium.com

By @posth.me , @liccium.com

FAIA: AAC; AC: Co-Creation; ChatGPT, GPT 5.6 Sol