5. Legal Framework

Authentication Standards for Blockchain-Anchored Evidence

A photo submitted as pre-loss documentation enters a predictable sequence of challenges. Opposing counsel questions when it was taken. The file metadata shows a timestamp. Counsel argues metadata is editable. The phone manufacturer's logs show a creation date. Counsel argues the phone clock can be manipulated. The claimant's testimony affirms the date. Credibility becomes the issue, and credibility is exactly what litigation is designed to contest.

This is the authentication problem for digital evidence. The federal rules for resolving it are specific, numbered, and already in force.

FRE 901(b)(9): Process-Based Authentication

Federal Rule of Evidence 901 establishes the general standard: the proponent must produce sufficient evidence to support a finding that the item is what the proponent claims.

FRE 901(b)(9) provides a specific mechanism: authentication is satisfied by "evidence describing a process or system and showing that it produces an accurate result." This is the evidentiary foundation for blockchain timestamp authentication in federal proceedings.

Two points are worth stating plainly, because they are routinely conflated in legal and insurance practice.

First: FRE 901(b)(9) is not self-authentication. It requires a foundation, typically expert testimony or technical documentation, establishing that the anchoring process produces reliable, accurate results. The blockchain record alone does not authenticate itself under this rule. The process must be described and its accuracy demonstrated.

Second: authentication under 901(b)(9) is about the process, not the metadata. EXIF timestamps embedded in a file are metadata fields. They are not output from a certified process. When an authentication argument rests on EXIF data, opposing counsel has a straightforward response: the field is editable. Authentication under 901(b)(9) requires demonstrating that a systematic process produced the result and that the process works. A public blockchain ledger with independent validator consensus is a process. A metadata field written by the device is not.

FRE 902(13) and 902(14): Self-Authentication for Machine-Generated Records

The 2017 amendments to the Federal Rules of Evidence added two categories that substantially change the authentication burden for digital records.

FRE 902(13) provides for self-authentication of "a record generated by an electronic process or system that produces an accurate result, as shown by a certification of a qualified person" complying with the certification requirements in FRE 902(11) or (12). No live testimony required.

FRE 902(14) addresses copies of electronically stored information under the same certification framework.

The practical effect: a written certification from the party operating the anchoring process can satisfy authentication without calling a technical witness at trial. This matters in claims contexts where litigation is already resource-intensive. A written certification that describes the hash anchoring process, identifies the specific hash and its on-chain transaction records, and attests that the process produces accurate results satisfies the rule's requirements.

The certification approach is already established in federal practice for electronic records generally. FRE 902(13) extended it to machine-generated records specifically, reflecting the courts' recognition that these records are generated by process, not by human observation, and that human testimony about a machine's output is often less reliable than a certification describing how the machine operates.

Daubert and Process Reliability

In federal courts applying Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993), expert testimony about technical processes must satisfy reliability criteria: the methodology must be testable, subject to peer review, have a known error rate, and be generally accepted in the relevant field.

SHA-256 hashing and blockchain consensus mechanisms meet these criteria without meaningful controversy. SHA-256 is a NIST-standardized algorithm with mathematically established collision resistance. The Bitcoin and Polygon consensus mechanisms are public, documented, and independently audited by cryptographers worldwide. An expert offering foundation testimony under 901(b)(9) has a strong evidentiary record to draw on.

The dual-chain architecture strengthens this foundation. When the same SHA-256 hash is recorded on both Polygon and Bitcoin, two independent networks confirm the same fact. Each has different validator sets, different consensus logic, different global infrastructure. Agreement between them is not coordination. It's independent corroboration. From a Daubert reliability standpoint, dual-chain confirmation is a materially stronger position than single-chain.

Challenges and Their Limits

Blockchain timestamps are not immune to attack at trial, but the available challenges are narrow.

The most common challenge is temporal: did the anchor occur before or after the loss event? This is a factual question. The blockchain timestamp is publicly verifiable by any party with the hash and the transaction ID. If the anchor predates the documented loss date on the blockchain's ledger, that is the record. The argument fails unless the challenger can demonstrate that the loss itself occurred earlier than claimed, redirecting the dispute to a different factual question.

A second challenge concerns custody at the time of anchoring: did the file match the hash at the moment it was submitted? Nothing in the blockchain record prevents a party from altering a file and then anchoring the altered version. This is a custody argument, not a technical one. The response is documentation: when was the file created, by whom, on what device, and how was the original preserved between creation and anchoring. Chain of custody practices answer that question. The blockchain answers the separate question of whether the hash existed at a specific point in time. Neither replaces the other.

What cannot be challenged: the on-chain record itself. It is on a public ledger. It cannot be back-dated, altered, or deleted. Opposing counsel can verify it independently using the public verify endpoint at proofledger.io/api/v1/verify (no authentication required) or via the verify-proof PyPI package for offline verification. The verification is deterministic: the hash either matches the on-chain record, or it doesn't.

Proposed FRE 707

In June 2025, the Judicial Conference approved proposed FRE 707, a new rule specifically addressing machine-generated evidence. The public comment window closed in February 2026.

If adopted, FRE 707 would create an explicit evidentiary framework for records produced by automated systems, distinct from existing rules that address human-generated records with digital characteristics. Blockchain timestamps, which are fully machine-generated (no human observation or attestation involved in the anchoring process), fit the proposed rule's scope directly.

The proposed rule reflects a gap that has been apparent in federal practice for years. FRE 901 and 902 were written before blockchain infrastructure existed at scale. Courts have applied them to blockchain records by analogy, and that approach has generally held. But an explicit rule eliminates the foundation-laying exercise that 901(b)(9) currently requires. Organizations that establish consistent blockchain timestamp procedures before FRE 707's adoption will be positioned to take advantage of the streamlined admissibility path when the rule takes effect.

The Authentication Chain in Practice

A properly structured evidentiary submission using blockchain-anchored documentation follows a predictable sequence.

The file is SHA-256 hashed at the time of documentation and submitted for anchoring. The hash (not the file) is recorded on Polygon, typically within the same session, and included in a Bitcoin merkle batch within 24 hours. A proof record is generated with a certificate URL and transaction IDs for both chains. The file itself never leaves the submitting party's possession.

At the point of a dispute, the proof record is preserved alongside the original file. A certification can be issued describing the anchoring process and the specific on-chain record. That certification supports self-authentication under FRE 902(13) without live testimony.

Any party to the proceeding can independently verify the record. The hash, the transaction IDs, and the block timestamps are public. The verification tools are public. There is no proprietary system that opposing counsel cannot inspect.

That transparency is the point. The authentication argument doesn't depend on trust in the anchoring platform. It depends on the blockchain's properties: public, immutable, independently verifiable. The legal framework for those properties is already written.