Expert Analysis and Statement of a European Patent Attorney on Proofbox

At Proofbox, formal compliance and global findability are not an afterthought — they are the core of our offering. To further validate our publishing process, we commissioned a comprehensive expert analysis by a licensed representative before the European Patent Office. The goal: to assess whether a technical disclosure published via Proofbox can be recognized as prior art before courts and patent offices in Europe and the United States. This approach acknowledges that recognition before a court can only be established after a judicial ruling.

The analysis focused on whether defensive publications made through Proofbox meet the formal and practical requirements to be accepted as effective prior art, particularly before the EPO, the Unified Patent Court (UPC), and the USPTO.

We are proud to share this in-depth analysis below.

Expert Opinion on Proofbox Disclosures

The evaluation of online publications with respect to their suitability as prior art under the European Patent Convention (EPC) and U.S. patent law requires a nuanced analysis of the underlying technical and legal framework conditions. The subject of this analysis is a specific form of online publication provided through the Proofbox platform. Proofbox enables users to upload a technical document for a fee into a publicly accessible, web-based archive. Each document is timestamped via a qualified eSeal, hashed, published in an SEO-optimized blog format with a unique URL, and monitored for permanent availability through daily retrieval logs. Furthermore, the archive can be filtered by publication date, enabling systematic and chronological traceability of priority-relevant information. Additionally, Proofbox features a semantic, AI-based search function that enables content-related access to publications. Users can not only search for specific topics or keywords but also automatically receive thematically related documents. This significantly increases the actual and documentable discoverability of individual publications and enables searchability that corresponds to the standards referenced in EPO case law on public accessibility of library holdings (e.g., T 834/09, T 314/99). Access to the information is thus ensured not only formally but also in practice.

According to Art. 54(2) EPC, the state of the art comprises everything made available to the public before the filing date. The consistent case law of the EPO, in particular decision G 1/92, specifies this provision to mean that an item is made available to the public if there was no confidentiality obligation and a skilled person could access the information using ordinary means (G 1/92, OJ EPO 1993, 277). Decision T 482/89 further emphasizes the principle of free evaluation of evidence, whereby any evidence that appears suitable for establishing facts may be considered (T 482/89, OJ EPO 1992, 646).

The EPO Guidelines confirm that online publications can constitute prior art, provided the publication date is verifiable and access was not restricted. Section G-IV, 7.5 of the Guidelines clarifies that even content behind a paywall may be considered public if there is no confidentiality obligation and access is generally possible (EPO Guidelines G-IV, 7.5). A paid publication is therefore not per se excluded from the public domain. The EPO draws a parallel to purchasing a textbook or journal article, for which a fee is also charged. The key requirement is that access does not depend on selection processes or individual approval, but is open to anyone willing to pay. This applies to the Proofbox model.

The main challenge lies in proving the time and immutability of the publication. The EPO emphasizes the need for credible proof of the publication date, which is to be assessed on the balance of probabilities (EPO Guidelines G-IV, 7.5.2). This does not require absolute certainty, but rather a convincing demonstration that publication occurred at the stated time. Mere assertions without evidence are insufficient; on the other hand, no mathematical proof is required. T 750/94 highlights that in serious matters such as the validity of a prior publication, strict requirements are placed on the evidentiary value of the submitted documents (T 750/94, OJ EPO 1998, 32).

In the case of Proofbox, the publication date is proven by a digital and qualified timestamp generated by a qualified trust service provider. These timestamps are eIDAS-compliant (EU Regulation No. 910/2014) and thus meet European requirements for qualified electronic time evidence. The embedding of the document hash into the timestamp via a qualified eSeal also ensures document integrity. This practice complies with ISO/IEC 18014 and ISO/IEC 27001 and forms the basis for a reliable chain of custody for content and date.

Moreover, the corresponding hash value is embedded in the document's eSeal, enabling full traceability of any changes. Availability is monitored server-side at least daily and recorded in a tamper-proof log. Each publication is accessible via a permanent, individualized URL, equipped with SEO metadata, and indexable by search engines, thus fulfilling the public accessibility requirement referenced in decision T 2/09 (PHILIPS), according to which documents findable via web search engines are generally publicly available (T 2/09, point 4.8).

A remaining risk lies in how different boards of the EPO evaluate such evidence. Decision T 1961/13 (COLUMBIA UNIVERSITY) shows that the EPO may apply a strict standard when assessing public accessibility. In that case, the online availability of a document was denied because the archiving mechanisms and exact date could not be sufficiently substantiated (T 1961/13, points 4 and 5). This decision illustrates that even a plausible Google index entry without reliable archive sources or timestamp evidence is insufficient.

Under U.S. patent law, the relevant standard is 35 U.S.C. § 102(a)(1), which covers any "printed publication" made publicly accessible before the relevant filing date. According to MPEP § 2128, online publications must be both publicly accessible and permanently available. A publication behind a paywall is permissible provided access is possible and no confidentiality obligation exists. The USPTO accepts digital timestamps and archived content under certain conditions but requires objective verifiability of the date.

Proofbox provides a robust level of documentation by U.S. standards, particularly through eIDAS-compliant timestamping, hash protection, public URL, SEO optimization, and logging of ongoing online availability. In a legal dispute, however, a U.S. court or the USPTO would need to assess whether the technology employed and the chain of evidence meet the authentication and accessibility requirements. U.S. case law on online publications tends to be pragmatic and places particular emphasis on archived and verifiable sources (e.g., Wayback Machine, DOI, or published metadata).

Additionally, the new Unified Patent Court (UPC) must be considered. The UPC follows the EPC in substantive law and applies its own rules of procedure. Under Rule 262.2 of the UPC Rules of Procedure, the principle of free evaluation of evidence also applies. Electronic documents are expressly admissible as evidence, provided their authenticity and relevance can be sufficiently demonstrated. The combination of eIDAS-compliant timestamps, documented public availability, and secure logging suggests that a Proofbox publication would be admissible as evidence before the UPC, particularly if a technical expert is called upon to validate the digital evidence. Nevertheless, some uncertainty remains as the UPC has not yet ruled on comparable internet publications.

Ultimately, the recognition of Proofbox documents in proceedings before the EPO, UPC, or in U.S. court proceedings depends on the persuasiveness of the evidence presented. The EPO operates on the principle of free evaluation of evidence, where each piece of evidence is assessed by its weight (T 482/89). The use of a qualified timestamp, tamper-proof archiving mechanisms, and documented public accessibility supports a high evidentiary value. Nevertheless, legal uncertainty remains as no judicial decision has yet addressed a publication mechanism directly comparable to Proofbox.

In summary, the technical and organizational measures implemented by Proofbox are, under current law in Europe, before the UPC, and under U.S. law, fundamentally suitable to produce an online publication that qualifies as prior art. This is conditional on consistent proof of publication date, content, immutability, and public accessibility being provided in each individual case. The evaluation of evidence remains reserved for the competent authority or court. Based on existing case law, in particular G 1/92, T 482/89, T 750/94, T 2/09, and T 1961/13, as well as the UPC Rules of Procedure, recognition as prior art is likely but has not yet been confirmed by a precedent. The requirements in the U.S. are similar and focus on objective verifiability and permanent availability. Proofbox's measures are aligned with these standards but are ultimately always subject to case-specific review.

Notice

Due to legal restrictions under unfair competition regulations in certain jurisdictions, the identity of the expert cannot be disclosed publicly. If you have questions or wish to discuss technical aspects of discoverability or recognition as prior art, please contact us via our contact form. We will be happy to connect you with the person behind this analysis.

Alternatively, for further legal questions, you may also consult any registered person authorized to represent before the European Patent Office or any U.S. patent attorney through the following public registers:

• EPO Register (European Patent Attorneys)
• USPTO Register (US Patent Attorneys)