Evidence in practice
Blockchain evidence has already been used in court.
Real disputes. Documented decisions. See where blockchain records made a difference, and what mattered alongside them.
Explore the casesThe surrounding evidence connects the story.
- Admissibility
- Can the court consider it?The record must meet the applicable evidence rules.
- Probative weight
- What does it establish?Integrity, timing, authorship and truth are different questions.
01 / File records
File evidence in real disputes
Designs, webpages and video. Records considered alongside the surrounding evidence and the question before the court.
AZ Factory v. Valeria Moda
Timestamps helped connect design files to an earlier date, alongside other evidence.
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AZ Factory v. Valeria Moda
Timestamps helped connect design files to an earlier date, alongside other evidence.
Read case & sourcesClose caseMarseille Judicial Court · France · RG 23/00046
In a fashion-design copyright dispute, the court relied on blockchain timestamp reports for design files, a judicial officer’s verification and evidence of public disclosure in finding for AZ Factory.
The dated fingerprints contributed to a successful claim alongside evidence connecting the designs to the claimant.
Huatai v. Daotong
Recorded hashes and capture logs helped establish reliable webpage evidence.
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Huatai v. Daotong
Recorded hashes and capture logs helped establish reliable webpage evidence.
Read case & sourcesClose caseHangzhou Internet Court · China · (2018) Zhe 0192 Min Chu 81
The court accepted webpage evidence whose hashes had been recorded on Bitcoin and Factom. Screenshots, source code and logs corroborated how it was captured, and the claimant received damages.
The court examined both the blockchain record and the reliability of the underlying evidence.
Microvision Horizon v. Baidu
The evidence was acknowledged. The infringement claim still failed.
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Microvision Horizon v. Baidu
The evidence was acknowledged. The infringement claim still failed.
Read case & sourcesClose caseBeijing Internet Court · China · Short-video copyright dispute
The plaintiff collected evidence through a third-party blockchain platform, and the defendants acknowledged it. The court described blockchain as a reliable way to maintain content integrity.
The defendants still prevailed on the separate infringement question. Reliable file evidence and the legal merits are separate parts of a case.
Social-media preservation appeal
The court noted blockchain preservation while refusing urgent relief.
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Social-media preservation appeal
The court noted blockchain preservation while refusing urgent relief.
Read case & sourcesClose caseSão Paulo Court of Justice · Brazil · AI 2237253-77.2018.8.26.0000 · judgment p. 5
In a dispute over allegedly offensive social-media posts, the appellant said he had preserved the content through OriginalMy. The court cited that preservation when refusing a request to keep third parties unaware of the proceedings, and dismissed the appeal for interim relief.
This was a procedural decision. It did not establish that the posts were defamatory, conduct a general audit of blockchain reliability or make all blockchain records admissible.
02 / Transaction records
Other blockchain evidence in U.S. courts
These cases concern cryptocurrency transfers and transaction analysis, rather than timestamps on customer files.
United States v. Sterlingov
Expert Bitcoin-tracing testimony was admitted; the appeal upheld that decision.
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United States v. Sterlingov
Expert Bitcoin-tracing testimony was admitted; the appeal upheld that decision.
Read case & sourcesClose caseU.S. Court of Appeals · D.C. Circuit · No. 24-3161 · opinion pp. 19–23
The appeals court upheld admission of expert testimony using Chainalysis Reactor to trace Bitcoin transactions. It considered explanations of the methods, reliability checks and corroborating evidence.
This decision concerns expert transaction analysis. It does not decide how a court would assess a timestamp on a customer’s file.
United States v. Costanzo
The jury saw blockchain verification evidence in a cryptocurrency-transfer case.
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United States v. Costanzo
The jury saw blockchain verification evidence in a cryptocurrency-transfer case.
Read case & sourcesClose caseU.S. Court of Appeals · Ninth Circuit · No. 18-10291 · opinion pp. 6–10
The opinion describes trial evidence about Bitcoin transfers, including a blockchain verification screenshot shown to the jury. The court affirmed the conviction when reviewing the interstate-commerce element.
It documents blockchain information used at trial; the published ruling concerns cryptocurrency transfers and federal jurisdiction.
03 / Authentication
Cryptography beyond timestamping
Document forensics and hash certification offer related lessons. These decisions are not approvals of blockchain timestamping services.
COPA v. Wright
Technical inconsistencies helped expose backdated documents.
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COPA v. Wright
Technical inconsistencies helped expose backdated documents.
Read case & sourcesClose caseHigh Court of Justice · England and Wales · [2024] EWHC 1198 (Ch)
The court rejected Craig Wright’s claim to be Satoshi Nakamoto after examining extensive forensic and other evidence. File metadata, software history, cryptographic material and corroborating records helped test the claimed dates and authenticity of documents.
This illustrates forensic scrutiny of a claimed history, rather than judicial approval of a file-timestamping service. The written reasons followed declarations made on 14 March 2024. They also discuss backdating findings from the earlier Kleiman litigation.
Pune Bar Association v. Union of India
Hash disclosure and expert certification survived a constitutional challenge.
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Pune Bar Association v. Union of India
Hash disclosure and expert certification survived a constitutional challenge.
Read case & sourcesClose caseSupreme Court of India · W.P. (Civil) 599/2026
The court rejected the arbitrariness challenge to the certificate requirements under Section 63(4) of the Bharatiya Sakshya Adhiniyam. It described hash disclosure and expert certification as rational safeguards for the authenticity and integrity of secondary electronic evidence.
This concerns electronic-evidence certification, not blockchain timestamping or a universal SHA-256 mandate. The court left the question of who may qualify as the Part B expert open, while removing the cited restrictive High Court view’s binding effect.
The method matters
How courts evaluate the technical architecture.
The useful distinction: what happened before the record, and what can be checked after it. The precise legal test depends on the jurisdiction.
- 01Capture the source
- 02Compute the hash
- 03Anchor the record
- 04Verify the match
Was the source reliable?
Capture methods, source files, collection logs and corroboration help explain where the evidence came from. An accurate hash can still describe a manipulated file.
Does the proof check out?
The original file, hash calculation, chain reference and verification method connect the retained bytes to the earlier record. A match supports integrity, not every claim about the content.
How the rules differ
ChinaSeparate the record from its source
Articles 16–19 of the 2021 Online Litigation Rules allow a finding of no post-anchoring alteration after technical verification, subject to contrary evidence. Courts can examine platform reliability, capture methods and authenticity before anchoring, with expert help where needed. These are rules of the Chinese courts, not a worldwide presumption.
European UnionElectronic form and qualified status are different
eIDAS Article 41 protects electronic timestamps from rejection solely because they are electronic or non-qualified. Qualified timestamps receive specific presumptions about time and integrity. Article 45k makes a similar distinction for electronic ledgers. A public-chain record does not, by itself, acquire qualified status or establish the whole claim.
BrazilPreserving a post does not settle its truth
The São Paulo appeal shows why the procedural question matters. The court noted the appellant’s blockchain preservation, but reserved a fuller assessment of removal and user-identification requests for the trial court. It did not decide that the recorded statements were true or that every blockchain capture replaces a notarial record.
United StatesAuthentication still needs a proper foundation
Federal Rules of Evidence 902(13) and 902(14) provide certification routes for electronic processes and digitally identified copies, with qualified-person certification and notice requirements. Matching hashes can authenticate a copy. Relevance, hearsay and other objections remain separate; a blockchain receipt is not automatically a compliant certification.
Four gaps a timestamp cannot close
Strong records still need a complete story.
01A timestamp does not name the author
Connect the file to the person.
Someone can record a file they did not create. Keep draft histories, agreements, delivery messages and other evidence of attribution alongside the dated fingerprint.
02A hash cannot repair a staged capture
Explain how the evidence was collected.
A manipulated screenshot can be hashed just as easily as an accurate one. Preserve capture logs, source material and any independent witness or collection procedure. Post-anchoring integrity cannot establish pre-anchoring truth.
03The original still matters
Keep a byte-for-byte copy.
Re-saving or re-exporting a file can change its hash. The altered copy will not match the earlier record. Retain an unchanged original and backups; a digest cannot reconstruct a lost file.
04The proof must remain checkable
Export the evidence and its verification path.
Some systems require a Merkle path or other supporting data to connect a file to a chain record. Retain everything needed for that system, along with suitable chain-history access. Open verification reduces provider dependence; it does not guarantee future availability or legal acceptance.
How Quantum Notary’s record is checked
Quantum Notary records each file’s own 32-byte SHA-256 digest directly in Base transaction calldata. An independent verifier hashes the retained file and compares it with the slot identified by the receipt’s batchIndex. Keep the original, exported proof and transaction reference; checking also requires suitable Base history.
This establishes a byte match to the record, not authorship or truth. The service’s finalized status means it observed a successful Base L2 receipt, not Ethereum L1 settlement.
See the independent verification stepsYour evidence, in three parts
Keep more than a timestamp.
A matching fingerprint and Base record support exact-file integrity and existence by the recorded date. Keep these together.
- 01
The exact file
Keep the original bytes. Editing or re-exporting can change the fingerprint.
Original, unchanged - 02
The exported proof
Save the receipt and included proof PDF. Independent checking also needs access to Base history.
Receipt + proof PDF - 03
The surrounding story
Keep drafts, agreements and messages that connect the file to your dispute.
Context + supporting records
These cases concern other systems and their particular facts. They do not evaluate Quantum Notary or its Base implementation. Courts decide what to accept, its weight and the outcome; none is guaranteed.
What a file record establishesStart with the original
Make the record.
Before the dispute.
One file. One credit. Proof PDF included.