A defensible chain of custody for AI-assisted review.

CHP’s evidence is SHA256 hash-chained — which is, almost literally, chain of custody. This page shows how it would work for legal work with today’s primitives; the matter-level retention and access layer is what we build with a design partner.

Read the essay: “Chain of custody for AI-assisted review” →

The pain

AI now reads, summarizes, and flags documents in review and e-discovery. When the work product is questioned, you need a defensible record of what the model touched, what a person decided, and that the record is intact — chain of custody, not a screenshot.

The trigger

Opposing counsel, a court, or an internal risk review asks: “Show the provenance of this AI-assisted review, and demonstrate it hasn’t been altered.” Without a tamper-evident record, the work product is exposed.

Who owns it

General counsel and legal operations — accountable for defensibility, privilege, and the integrity of the review record.

What CHP would do

Every action — a model reading a document, a reviewer asserting or waiving privilege — is a governed event in a SHA256 hash-chained record, correlated by matter. Privilege becomes an explicit approve/deny decision, and the chain itself proves the record was not altered after the fact.

The demonstrated record

Every action, in a chain that proves itself.

This is a CHP evidence event: a stable action id, the host, the correlation that ties it to the matter, an explicit outcome, and a hash that links it to the prior event. Alter any record and the chain breaks — which is exactly what defensibility requires.

Demonstrated, not yet shipped: hash-chained evidence and replay exist today. Matter-level retention, access control, and export are what we build with a design partner.

evidence event — hash-chained

json

{
  "event_id": "evt_8f3a1c",
  "event_type": "execution_completed",
  "invocation_id": "inv_session_abc_001",
  "capability_id": "payments.transfer",
  "capability_version": "1.0.0",
  "host_id": "my-host",
  "correlation": { "correlation_id": "session-abc" },
  "sequence": 2,
  "timestamp": "2026-06-03T00:14:22.104Z",
  "outcome": "success",
  "payload": { "duration_ms": 43 },
  "redacted": true,
  "assurance": { "level": "S1" }
}

Using AI in review or e-discovery?

Bring a real review workflow. We’ll map provenance and privilege onto the protocol and build the retention and access your matters require, together.

Build it with us