> ## Documentation Index
> Fetch the complete documentation index at: https://docs.algovoi.co.uk/llms.txt
> Use this file to discover all available pages before exploring further.

# Verifiable Archive

> Tamper evident, post quantum document archiving: every document is content addressed, encrypted at rest, and recorded in an append only chain you verify.

<Note>
  **Also in the on-prem suite.** This product is included in the [AlgoVoi Compliance and Payments On-Prem Suite](/substrate-2), one commercial licence that unlocks and runs the complete self-hosted platform.
</Note>

## What it is

**Verifiable Archive** is evidence-grade document archiving: prove a document existed at a point in
time, hasn't been altered, and sits in a record that can't be back-dated, reordered, or silently
deleted. Every document is **content-addressed**, **encrypted at rest**, and recorded as a
**post-quantum-signed** entry in an **append-only, hash-linked chain** that anyone can verify offline.

It is **not** a document-management system — no folders, sharing, or search. It is the *evidence
layer* for documents: integrity, provenance, and verifiable retention, for records that must stand up
to an audit or a regulator years later.

<CardGroup cols={2}>
  <Card title="Tamper-evident chain" icon="link">
    Each entry is signed and linked to the one before it. Any alteration, insertion, deletion,
    reorder, or back-date breaks verification — tampering is detectable, not deniable.
  </Card>

  <Card title="Post-quantum, both axes" icon="shield-halved">
    Entries are Falcon-1024 signed; documents are encrypted with ML-KEM-1024 + AES-256-GCM. Records
    kept for decades stay verifiable and confidential past the migration to post-quantum cryptography.
  </Card>

  <Card title="Encrypted at rest, one method" icon="lock">
    Encryption happens in the engine, before storage — so a local-disk archive and an S3 archive are
    sealed identically. Storage only ever sees ciphertext.
  </Card>

  <Card title="Reporting & auditing built in" icon="clipboard-check">
    Signed audit reports, continuous integrity attestations, retention/compliance reports, and
    portable evidence packs — exported to your SIEM, Grafana, and GRC tools.
  </Card>
</CardGroup>

## What you get

* **Evidence-grade integrity.** A document's hash is bound into a post-quantum-signed entry; the
  chain proves the whole archive's order and completeness. Verification needs only the public key.

* **Encryption with one method, everywhere.** ML-KEM-1024 + AES-256-GCM (a fresh per-document key) on
  local disk or S3 alike — the storage target is a plug-in, the cryptography is not.

* **Storage you choose.** A local-filesystem backend for on-prem and air-gapped deployments, or an
  S3 / S3-compatible backend (Amazon S3, MinIO, Cloudflare R2, Wasabi) for durable object storage —
  same evidence model either way.

* **Reporting and auditing that proves continuity.** A read-only auditor produces signed audit
  reports and *continuous* integrity attestations — chained "still intact as of T" proofs of custody —
  plus retention reports and regulator-verifiable evidence packs.

* **Feeds the tools you already run.** Audit events and metrics export to SIEM (JSON-lines, syslog,
  CEF), Prometheus/Grafana (`/metrics`), and GRC/BI (CSV) — it owns the cryptography and integrates
  with your dashboards, rather than replacing them.

* **Optionally Substrate 2-bound.** Fold archive entries and audit reports into the broader
  [Substrate 2](/substrate-2) evidence chain.

## How it works

| Step         | What happens                                                                                  |
| ------------ | --------------------------------------------------------------------------------------------- |
| **Archive**  | Hash the document, encrypt it, and record a signed entry linked to the previous one.          |
| **Verify**   | Check any entry — or the whole chain's integrity and ordering — offline, from the public key. |
| **Retrieve** | Fetch and decrypt a stored document, integrity-checked against its recorded hash.             |
| **Audit**    | Produce signed reports, continuous attestations, retention reports, and evidence packs.       |

## Packages

| Capability                 | What it is                                                                   |
| -------------------------- | ---------------------------------------------------------------------------- |
| **Engine + local backend** | The archive engine and a local-filesystem backend — on-prem, air-gapped.     |
| **S3 backend**             | S3 / S3-compatible object storage (Amazon S3, MinIO, R2, Wasabi).            |
| **Auditor**                | Read-only reporting & auditing with SIEM / Prometheus / GRC export adapters. |

## Backups

Notarise every backup into the archive's tamper-evident, post-quantum chain — record just its hash
(no double-storage) or encrypt and store the bytes:

```python theme={null}
import hashlib
from algovoi_doc_archive import Archive, LocalFsBackend, HybridPqcEncryptor, signing
from algovoi_doc_archive.encryption import generate_mlkem_keypair

# One-time keys: Falcon-1024 signs entries; ML-KEM-1024 encrypts documents.
pk, sk         = signing.generate_keypair()
kem_pk, kem_sk = generate_mlkem_keypair()        # keep kem_sk offline — needed only to restore

# Public ML-KEM key only → the backup host can sign + encrypt, but cannot read past backups.
arc = Archive(secret_key=sk, public_key=pk,
              storage=LocalFsBackend("/srv/archive"),
              encryptor=HybridPqcEncryptor(kem_pk))

backup = open("db-2026-06-09.sql.gz", "rb").read()

# Hash-only: record existence + integrity, no extra storage.
e = await arc.notarize(doc_hash="sha256:" + hashlib.sha256(backup).hexdigest(),
                       title="db-2026-06-09", metadata={"host": "db01"})

# ...or encrypt-and-store the bytes (post-quantum encryption at rest):
# e = await arc.notarize(data=backup, title="db-2026-06-09", content_type="application/gzip")

assert (await arc.verify_chain()).valid          # whole-chain integrity + ordering — offline
```

* **Write-only nodes** — give the backup host only the ML-KEM *public* key; the secret key lives in an
  offline vault and is needed only to `retrieve()` and restore.
* **Two modes** — *hash-only* is a signed, ordered, tamper-evident ledger of your existing backups with no
  extra storage; *encrypt-and-store* also keeps the bytes encrypted at rest (ML-KEM-1024 + AES-256-GCM).
* **Independent audit** — anyone holding the Falcon public key can verify the entire chain offline, with
  no AlgoVoi service and no secret. Swap `LocalFsBackend` for the S3 backend for object storage, same chain.

## Cryptography

* **Post-quantum on both axes.** Entries are signed with Falcon-1024 (NIST Level 5); documents are
  encrypted with ML-KEM-1024 + AES-256-GCM. Both the integrity (signatures) **and** the confidentiality
  (encryption) are post-quantum — not just the signatures.
* The append-only chain is SHA-256-linked (quantum-resistant) and verifies offline.
* **Canonical form verified across 8 implementations.** Entry preimages use RFC 8785 (JCS)
  canonicalization — the discipline in AlgoVoi's open [conformance corpus](/conformance-vectors). A real
  archive entry canonicalized byte-identically across eight independent JCS implementations (Python,
  Node.js, Ruby, PHP, Go, Rust, Java, .NET), so the exact bytes a signature covers are reproducible in
  your own stack. The 8-language guarantee is the canonical form; the Falcon-1024 signature is verified
  with the published Python reference.

## Why commercial

The engine, verifier, and auditor were never published as open source — there is no free tier to
fall back on. It is offered as a **commercial product** because the value is in maintained,
quantum-resistant, evidence-grade archiving:

* **Embed without attribution overhead.** A commercial OEM licence lets you ship it inside your own
  product with no open-source notice obligations.
* **Enterprise terms.** Support, warranty, and a defined relationship — for a records-critical
  dependency.
* **Maintained crypto suite.** Post-quantum primitives and long-horizon record formats are ongoing
  work, bundled into the licence.

## Who it's for

* **Regulated record-keeping** — broker-dealers, investment firms, and any organisation with
  tamper-evident, long-horizon retention obligations.
* **Legal, IP, and contracts** — proof a document or invention existed on a date, unaltered.
* **Healthcare and public sector** — long-lived immutable records, including air-gapped on-prem.
* Anyone who needs **records that an auditor or regulator can verify independently**, without
  trusting the storage vendor.

## Get Verifiable Archive

Verifiable Archive is an **additional, separately-licensed package** — an add-on that binds to
Substrate 2, not part of Substrate 2 itself. It is available **self-serve as a Starter licence (perpetual one-time or annual)** (see below) and as a **commercial OEM SDK** and is
included in the AlgoVoi Enterprise and [On-premise](/on-premise) plans. It is not distributed on
public package registries.

<Card title="Buy Starter licences" icon="cart-shopping" href="https://api.algovoi.co.uk/suite-store">
  Three Starter licences — **perpetual (one-time) or annual subscription**, self-hosted, paid in **USDC**: **Verifiable Archive**, **S3 backend** (needs the Archive), and **Archive Auditor** (needs the Archive). The [store](https://api.algovoi.co.uk/suite-store) shows current pricing for each (and for both models) and issues your licence key + install command; set `ALGOVOI_LICENSE_KEY` to run. Enterprise / OEM: [email us](mailto:hello@algovoi.co.uk).
</Card>