Because Proof Deserves a Permanent Identity: eSeal and DOI at Proofbox

On June 4, 2026, Proofbox GmbH became an official member of Crossref. For Proofbox, this step is far more than an administrative footnote: from now on, every defensive publication released through Proofbox receives a persistent Digital Object Identifier (DOI) in addition to its existing qualified eSeal, the same identifier standard used by scientific journals worldwide. As a result, every piece of evidence documented through Proofbox gains a permanent, globally unique identity that remains citable, discoverable, and verifiable independent of the continued existence of any single website or provider.

This milestone is a good opportunity to outline how Proofbox's approach differs, in some key respects, from established providers of defensive publication such as IP.com and Research Disclosure, two names that have represented the industry for decades.

Two Established Traditions of Defensive Publication

Research Disclosure dates back to 1960 and was originally published as a printed technical journal. The brand has been part of the Questel Group (Questel Ireland Ltd) since 2011, which acquired it from Kenneth Mason Publication. New disclosures are now published online first and subsequently assigned to consecutive journal issues, so the journal-based format from its early years still shapes the service today. IP.com was founded in 2000 and, from the outset, built a purely digital model, the Prior Art Database (PAD), now part of the InnovationQ platform. Both providers have established themselves as recognized institutions in the industry over many years.

A shared characteristic of both models is that interested organizations can purchase paid subscriptions, such as InnovationQ+ at IP.com or Orbit Innovation at Questel, to gain full-text search access to the entire database. For many use cases, such as classic patent searching, this is a sensible and well-established model. For inventors and authors whose primary concern is preserving their own freedom to operate, however, a fully searchable archive can also mean that competitors or automated analysis tools with a corresponding subscription can search specifically for particular topics or technology fields.

Proofbox Publishes Differently: Discoverable, but Without Automated Full-Text Monitoring

To meet this specific need, creating publicly verifiable prior art without enabling automated competitor and technology monitoring with full access to the entire document content, Proofbox has chosen a complementary approach. Every publication is released exclusively as a pure internet publication, without an accompanying print edition and without a database offering comprehensive full access. Proofbox's archive is publicly discoverable and searchable through structured metadata, a dedicated sitemap, and semantic search functions, for patent offices, courts, and other authorized parties as well as for search engines. The complete content of individual documents, by contrast, is deliberately not retrievable in full text by bots, crawlers, or automated scraping tools.

As a result, every publication is available as publicly discoverable prior art, without third parties being able to access the entire document content in an automated, full-text manner and thereby conduct systematic competitor or technology monitoring. This balance between public discoverability through metadata and controlled access to the full content is one of the aspects in which Proofbox's model differs from IP.com and Research Disclosure.

The Qualified eSeal as the Foundation of Future-Proofing

To make data integrity and the exact time of publication permanently verifiable, Proofbox applies a qualified, eIDAS-compliant eSeal to every single publication. To the best of Proofbox's knowledge, neither IP.com nor Research Disclosure applies a comparable qualified electronic seal. It is precisely this eSeal that, to a large extent, underpins the future-proofing of a Proofbox publication: a qualified eSeal under eIDAS is generally recognized worldwide, explicitly including in North America. Both the USPTO and U.S. courts require objectively verifiable data integrity and robust proof of timing for an online publication to be recognized as prior art, among other things under the standards of MPEP § 2128, precisely the properties that a qualified eIDAS eSeal provides. Only in China may recognition be questioned in individual cases depending on the reviewing organization, which is one of the reasons why the additional issuance of DOIs serves as a further safeguard.

DOI as a Second Layer of Trust: Why Proofbox Is Now a Crossref Member

To further strengthen the authority and recognition of each individual publication, Proofbox has now introduced a second, independent layer of trust: the DOI. As a Crossref member, Proofbox assigns a persistent Digital Object Identifier to every published document, the same standard that scientific journals worldwide rely on to keep their publications permanently citable. Implementing a qualified eSeal and a DOI together for every single publication is a distinguishing feature. This combination of cryptographically secured data integrity and an internationally recognized, persistent identifier forms the technical foundation on which Proofbox builds its future-proofing.

This comprehensive safeguarding of integrity has already been acknowledged externally. For instance, the Swiss Federal Institute of Intellectual Property (IGE) lists Proofbox on its official page on alternatives to patenting alongside IP.com and Research Disclosure as a platform for defensive publication, a notable external confirmation that Proofbox is perceived as a serious complement to providers that have been established for decades.

Beyond public discoverability, Proofbox is in coordination with the European Patent Office (EPO) and the World Intellectual Property Organization (WIPO) to provide patent office examiners with searchable full access to publications through a central interface, exclusively for this group of users and exclusively for examination purposes. Examiners at individual patent offices are already aware of the platform. Specifically, Proofbox is in contact with the EPO to be included in a central search infrastructure used by more than 40 patent offices worldwide.

Auditable Discoverability Replaces the Wayback Machine

Proofbox's pure internet publication deliberately avoids the need to additionally rely on the Wayback Machine or comparable external measures for evidence preservation. Instead, the discoverability of each individual publication, meaning every individual URL together with its associated DOI, is automatically checked at random intervals and at least daily. The result of each of these checks is logged in a continuous hash chain, similar in structure to a blockchain. As a result, not only is the content integrity of a document evidenced by the eSeal, but its ongoing discoverability itself is also fully auditable.

A New Standard for Legally Robust Defensive Publications

In sum, Proofbox thereby combines four layers of evidence preservation in a single solution: controlled, pure internet publication without a purchasable full-text database, the qualified eIDAS-compliant eSeal for integrity and timing, the persistent Crossref DOI as an additional, internationally established layer of trust, and the auditable discoverability of each individual publication, logged in a hash chain.

Proofbox's distinguishing feature is that it equips every publication with both a qualified eIDAS eSeal and a persistent Crossref DOI, while additionally logging its discoverability on an ongoing basis in an auditable hash chain, to the best of Proofbox's knowledge a uniquely comprehensive safeguard for defensive publications in this combination.

We are convinced that, with this combination, Proofbox sets a new standard for legally and judicially recognizable defensive publications, a standard that meaningfully complements the well-established journal and database models and gives inventors and innovators an additional, future-proof foundation to positively shape their freedom to operate and, with it, their room for innovation.