The Document That Proves Itself.

Conventional e-signature services prove a document in two ways. They embed their own digital certificate in the executed PDF, which a PDF reader can check for tampering. And they keep the document, its audit trail, and the details of everyone who signed it on their own servers, ready to produce if a signature is challenged.

Both methods work, but both depend on the provider. The certificate is only as good as the reader’s trust in the provider who issued it, and the archive is only there while the provider keeps it. The proof belongs to the provider, not to the client.

The archive also creates a risk of its own. Every document signed through a conventional service adds to a store of executed agreements: trust deeds, operating agreements, powers of attorney, account mandates, each one filed with the names and email addresses of its signers. For a business signing sales contracts, that may be an acceptable trade. For families whose planning depends on discretion, a permanent third-party archive of their structure documents is exactly what they should not have.

Encryption and access controls reduce the danger. They do not remove it. An archive that exists can be breached, subpoenaed, or misused. An archive that does not exist cannot.

Lighthouse E-Sign keeps documents only while they are out for signature, and then only in encrypted form: the file, every signature image, and the audit trail. When the last signature is applied, the executed copy is delivered and filed to the client’s record with the firm. E-Sign then permanently erases its copy of the document, the signatures, and the names and email addresses of everyone who signed. A document that is never collected is erased automatically within thirty days.

What remains is a fingerprint of the document, the date it was executed, and the location of its public record. None of it can be used to reconstruct the document or identify the people who signed it.

The fingerprint is a SHA-256 hash: a 64-character value computed from every byte of the executed document. The same document always produces the same value. Any change produces a completely different one. Replace a page, move a decimal point, or remove a schedule, and the fingerprint no longer matches. A forger cannot work backward from the fingerprint to make an altered document fit, because no practical method of doing so is known.

That is why page substitution, the oldest way to tamper with a long agreement, does not work against an E-Sign document. The fingerprint covers the whole executed file, not just the signature page.

At execution, E-Sign records the fingerprint, with the document’s reference number, on the Solana public blockchain. The entry contains no names and no personal information. It is written by a signing key held in a hardware security module, which cannot be copied out by anyone, including the firm’s own staff. Once written, the entry cannot be altered or withdrawn, and the ledger fixes the time it was made.

This is what sets the service apart. The proof no longer depends on the firm. Every executed document carries a Certificate of Execution with its reference number and a code linking to the public verification page. Anyone holding the document can open that page and select the file. The fingerprint is computed in their own browser, and the document is never uploaded. If it matches the public record, the document is exactly the one that was executed. If the firm, or E-Sign itself, ceased to exist, the record on Solana would remain, and anyone could still check the document against it.

A fingerprint proves that a document has not changed since it was executed, and when it was executed. It does not, on its own, prove who signed. That evidence comes from the signing process: each signer is invited by the Lighthouse officer handling the matter, confirms their identity with a one-time code sent to their email, and every step is written to a hash-chained audit trail, in which each event is bound to the one before it. Signing evidence is only as strong as the signer’s control of their own email account, which is why we ask clients to protect it.

Two practical points follow. First, verification checks the file exactly as delivered. A copy that has been re-saved, combined into a binder, or printed and scanned will not match, even if nothing in it has changed. Clients should keep the delivered file as their original. Second, whether an electronic signature is legally effective for a given document, in a given jurisdiction, is a matter of governing law, not of technology. Some instruments still require wet ink, a witness, or a notary, and for those the firm continues to arrange execution on paper.

The documents our clients sign are among the most consequential they will ever hold. They should not sit in someone else’s archive, and their authenticity should not depend on someone else’s word. Lighthouse E-Sign keeps nothing once a document is filed, and it leaves behind a public record that anyone can check and no one can rewrite. It is available to clients of the firm, and to the counterparties who sign with them, at no additional charge. More about the service is on the Lighthouse E-Sign page.

This note is informational and is not legal advice to any person. The legal effect of an electronic signature depends on the document, the parties, and the governing law.