enTrail

Verification

The .entv file Beta

A verification you can hand to someone. It carries the receipt that was checked, the answer the verifier gave word for word, and the receipt of the sealed record proving that check happened.

What it is for

A verification on a screen convinces the person looking at the screen. An auditor asking about a decision from March needs something they can keep, re-read, and check themselves months later. That is this file.

It is not a new kind of proof. It is a container for proofs you already have, plus the evidence that the check itself took place and was recorded.

PropertyValue
Extension.entv
Filename<box>-<event_id>-<verification_id>.entv
Media typeapplication/vnd.entrail.trail-verification+json
ContentsCanonical JSON, version 1
Built byThe box, on the server. No part of it is assembled in a browser.

Getting one

Verify an event in the trail explorer, then download the file from that verification. It becomes available once the record of the verification has itself been sealed, which takes roughly two minutes.

That wait is the point rather than a delay: the file includes the receipt for its own record, and that receipt cannot exist before the record is sealed.

Download
curl -sS -OJ \
  https://your-box.box.entrail.io/api/trail/<env>/verifications/<id>/entv

What a reader can check, without us

Three things, in this order, and none of them require enTrail software or an account.

  1. The record of the verification is sealed. Its receipt verifies like any other.
  2. The answer in the file is the answer that was sealed. Hash the verbatim answer and compare it with the hash inside the sealed record. If someone edited the wording afterwards, this fails.
  3. The original event's receipt verifies. This is the ordinary check described in verify a receipt, and it is where the actual proof lives.
Be clear about what this file proves. It is produced by the box's own verifier, so the answer inside it is not independent evidence on its own. What makes it worth anything are the receipts it carries: those verify against published keys and the Bitcoin anchor, with no enTrail service involved. Treat the file as a convenient envelope, and the receipts inside it as the proof.

Why the extension is what it is

An earlier release used .tv. That was changed deliberately. It is a domain ending, so a filename pasted into an email or a chat window can be turned into a link to a website, which is exactly the wrong behaviour for a proof file and an obvious opening for phishing. It is also already used by several unrelated programs.

.entv has no known use and is not a domain ending. A file already downloaded as .tv is byte-for-byte the same format, so renaming it is enough.

The format is not frozen yet. Its JSON schema is not yet published alongside the other contracts, so treat the field layout as settled in practice but not guaranteed. Build against the three checks above rather than against exact key names, and we will say here when the schema lands.