> ## 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.
# Recovery Vault
> Threshold (Shamir k-of-n) post quantum key recovery for any Substrate 2 key: data loss protection and identity continuity with no third party key use.
**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.
**Free for every Substrate 2 customer.** Recovery Vault protects **any key** in your deployment —
encryption keys *and* signing keys — at no additional charge. There is no separate licence to buy.
**Recovery Vault protects *keys*; [Records Vault](/records-vault) preserves *records*.** They share a
word and nothing else — Recovery Vault is threshold key recovery (this page); Records Vault adds
RFC-3161 timestamping, a read-access log, and legal holds for regulated health/legal records. Most
teams run both.
## What it is
**Recovery Vault** is threshold custody for the keys you can't afford to lose — starting with the one
whose loss is *catastrophic*: the master key that decrypts your [Verifiable Archive](/verifiable-archive).
It splits a key into **Shamir k-of-n shares** — any *k* of them reconstruct it, while any *k − 1* reveal
**nothing** — so a single lost or destroyed share never locks you out, and no single holder can use your
key.
**What it protects — and why it matters differs by key type:**
* **Encryption keys** (e.g. the Verifiable Archive ML-KEM master key) — loss means **permanent data
loss**. Here recovery is essential.
* **Signing keys** (e.g. your Substrate 2 receipt / agent-passport / federation keys) — loss would
otherwise force you to rotate and re-establish trust. Recovery preserves **identity continuity**, so
counterparties keep trusting your established public key.
By default it is pure **self-custody**: every share is yours and **AlgoVoi holds nothing**. Optionally,
you can enable **support-assisted recovery**, in which AlgoVoi holds **exactly one** share —
mathematically insufficient to decrypt anything on its own — so our support team can *contribute* that
one share to a break-glass recovery if you lose your own, **without ever being able to read your data
alone**.
Shamir k-of-n: any *k* shares rebuild the key, fewer reveal nothing. Lose a share — or a whole
custodian — and you still recover. No single point of loss, no single point of compromise.
Default: AlgoVoi holds nothing. Opt-in support recovery: AlgoVoi holds **one** share, which is
below threshold — it is not your key and cannot recover or read your data on its own.
Your data stays sealed with ML-KEM-1024 + AES-256-GCM, and the recovery envelope is Falcon-1024
signed — so its parameters and recipient set are tamper-evident into the post-quantum era.
The split uses SLIP-39 — the audited SatoshiLabs Shamir secret-sharing reference implementation —
over a 256-bit data key. No homegrown cryptography.
## What you get
* **Survive a lost key.** A destroyed laptop, a forgotten passphrase, a departed employee — none of
these has to mean losing access to years of encrypted records. Recover from any *k* of *n* shares.
* **Resilience without escrow.** Threshold custody means no single person or box — not even AlgoVoi —
can decrypt your data. The opposite of handing a vendor a master key.
* **Optional break-glass help.** Opt in and AlgoVoi support can contribute its single share if you're
ever stuck below threshold — assistance that still can't read your data.
* **Post-quantum and offline.** The same ML-KEM-1024 + AES-256-GCM that protects the archive; recovery
needs only the shares and the (non-secret) envelope — no AlgoVoi service to call.
* **Free with Substrate 2.** Included in the Verifiable Archive package at no extra charge.
## How it works
| Step | What happens |
| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Split** | The archive master key is sealed under a random 256-bit data key (AES-256-GCM); that data key is Shamir-split into *n* shares with a recovery threshold of *k* (SLIP-39). |
| **Distribute** | You hold the shares — across your own people, sites, or hardware. Optionally, **one** share is encrypted to AlgoVoi's published recovery key and embedded in the envelope (support-assisted, opt-in). |
| **Recover** | Gather any *k* shares → reconstruct the data key → unseal the master key. The recovered key is checked against a sealed **sentinel** before it is ever used. |
The **envelope** (the wrapped key + parameters) is *not* secret — it cannot be opened without *k*
shares — so you can store it alongside the archive. **Break-glass:** if you lose shares down to fewer
than *k*, AlgoVoi can contribute its single share on a verified request — enough to reach the
threshold *only* in combination with your remaining shares.
## Recovery flow
There are two ways to get your key back — which one you use depends only on how many shares you can
gather:
* **Self-recovery (no AlgoVoi involved).** Gather any *k* of your own shares, hand them to a fresh
vault, and the master key is reconstructed. If you keep *k* shares yourself, you never need anyone
else — this is the normal path.
* **Assisted break-glass (opt-in).** If you've lost shares down to *fewer* than *k* and you enabled
support-assisted recovery, send AlgoVoi the **non-secret envelope** on a verified request. AlgoVoi
unwraps its **single** share offline and returns it; combined with your remaining shares (*k* total)
it reconstructs the key. AlgoVoi never sees your other shares and never sees your data — one share is
below threshold and recovers nothing on its own.
Either way, recovery needs only the shares and the (non-secret) envelope — there is no AlgoVoi service
to call — and the recovered key is always checked against a sealed sentinel before it is accepted. Run
a periodic **recovery drill** so you know your shares actually reconstruct *before* you ever need them.
## Custody model
* **Self-custody (default).** All *n* shares are returned to you; **AlgoVoi holds nothing**.
* **Support-assisted (opt-in).** AlgoVoi holds **exactly one** share. One share is below threshold: it
decrypts nothing and cannot recover your data alone. AlgoVoi publishes only a recovery **public**
key; its matching secret is itself **Shamir-split across separate AlgoVoi officers**, so no single
person — at AlgoVoi or anywhere — can use it. Before opting in, verify AlgoVoi's published
recovery-key fingerprint: **`c8655d786306af53`**.
* **You choose *k* and *n*.** A common shape is **2-of-3**: keep two shares yourself (self-recover any
time) and let AlgoVoi hold one (assists only if you lose one of yours).
## Cryptography
* **Post-quantum at rest.** Documents stay sealed with **ML-KEM-1024 + AES-256-GCM** — identical to
the [Verifiable Archive](/verifiable-archive). Recovery never weakens that.
* **Signed envelope.** The recovery envelope is **Falcon-1024** signed (NIST Level 5), so its
threshold parameters and the support-share fingerprint are tamper-evident.
* **Audited threshold split.** The key is divided with **SLIP-39** (Shamir secret sharing, the audited
SatoshiLabs reference implementation) over a 256-bit data key — a standard, not a homegrown scheme.
* **Checked before use.** A recovered key must match a sealed sentinel before it is accepted, so a
wrong or tampered recovery fails closed.
## Integrate it
Recovery Vault drops into an existing AlgoVoi setup with minimal change — it runs *beside* your
services and holds the keys, so your application barely changes:
1. **Run the appliance.** Deploy the sealed container on your own host, bound to loopback, with an
unlock secret and API token supplied from your secret manager.
2. **Register your keys.** Generate a fresh archive (encryption) or signing keypair in the vault, or
import a key you already use. A **2-of-3 recovery is emitted automatically** — distribute the shares
to your own custodians.
3. **Use it in place.** Your services request the key from the vault over loopback when they need it —
to decrypt a [Verifiable Archive](/verifiable-archive) or sign a receipt. If a key is ever lost,
recover it from any two shares: self-service, or with AlgoVoi's one inert share for break-glass.
Nothing else changes — not your receipt formats, your chains, or your existing keys. Recovery Vault
wraps the keys you already use. The full API and deployment steps ship with the appliance.
## Who it's for
* **Anyone running [Verifiable Archive](/verifiable-archive)** who cannot afford to lose access to
encrypted records.
* **Regulated teams** that need a defensible key-recovery story **without vendor escrow** — a common
hard requirement in security reviews.
* **Operators who want threshold custody** of the master key across their own trustees, sites, or
hardware.
## Get Recovery Vault
Recovery Vault is a sealed, client-deployed appliance, **free for every Substrate 2 customer** — there is
no separate licence. It ships with the [Verifiable Archive](/verifiable-archive) and protects any key in
your deployment: enable it when you set up your archive keys, or register any other Substrate 2
signing key for threshold recovery.
Recovery Vault is included — set up your archive, then split your key for threshold recovery.
Planning custody across trustees or an HSM? We'll help you choose *k* and *n* and a recovery drill.