Timestamping and blockchain evidence

Timestamping is the process that associates a certain date and time with a document or with a digital fingerprint of it, in order to establish that it existed in that form at that moment. Blockchain evidence consists in recording the fingerprint of a file in a distributed ledger regarded as tamper-proof, whose dated entry can later be verified. In intellectual property, these techniques serve to establish the prior existence of a creation, an invention or know-how, alongside traditional methods such as the Soleau envelope or a deposit with a public officer.

Legal framework of evidence

Legal facts may be proved by any means (Article 1358 of the Civil Code), so that the prior existence of a creation may be established by any evidence, the court freely assessing the weight of the material produced. An electronic document has the same evidential value as a paper document provided that its author can be identified and that it is kept in conditions capable of guaranteeing its integrity (Article 1366 of the Civil Code). Regulation (EU) No 910/2014, known as eIDAS, recognises electronic timestamping as a trust service and attaches to qualified electronic timestamps a presumption of the accuracy of the date and time and of the integrity of the data. Its revision by Regulation (EU) 2024/1183 adds electronic ledgers to the list of trust services, which paves the way for qualified timestamping based on a blockchain.

Evidential value of a blockchain entry

Recording a fingerprint in a public blockchain establishes that the corresponding file existed at the date of the block, subject to two limits. The first concerns identification of the author: the entry proves the existence of the file, not the authorship or inventorship of the person who recorded it, which must be established by other evidence. The second concerns preservation of the original file, since the fingerprint allows no reconstruction and any later modification makes verification impossible. Without qualified timestamping, the entry is prima facie evidence that the court assesses freely, and the French courts have begun to accept such evidence when it is corroborated, without there yet being settled case law. A judicial officer’s report describing the entry and its verification usefully strengthens the file.

Uses in intellectual property

Timestamping is useful for proof of the date of creation of a work, for establishing prior personal possession that may be relied upon against a later patent, for putting in place the reasonable protective measures required of the holder of a trade secret, and for tracing successive versions of software or a design. It confers no right and replaces neither the filing of a title nor publication.

Key points

Timestamping and blockchain establish that a file existed on a given date, without proving who its author is or creating any right. Their weight is freely assessed and enhanced where the timestamp is qualified within the meaning of the eIDAS Regulation. Keep the original unchanged, document the identity of the person recording it and combine the entry with a traditional deposit for high value creations.

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This glossary entry is general in scope and does not constitute legal advice.

Dhenne Avocats litigates patent disputes before the Paris Judicial Court, the Paris Court of Appeal and the Unified Patent Court. When the question arises in a real case, the right moment is almost always before proceedings are issued.

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