> ## 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 Audit Log
> Append any business event to a tamper evident, post quantum chain. Entries are content addressed, append only and verifiable offline. Commercial OEM SDK.
AlgoVoi's Verifiable Audit Log is a tamper-evident, independently verifiable,
post-quantum-signed, append-only chain of business events you host yourself.
Every entry is content-addressed, Falcon-1024-signed and hash-linked to the one
before it, so an auditor recomputes the whole history offline against a published
public key, with no service and no vendor in the loop.
*Last updated: 20 August 2026.*
**Included in the [Verifiable Compliance Suite](/verifiable-compliance-suite).** One commercial licence installs this component together with the whole compliance estate, self-hosted and air-gap capable. It ships inside the suite, not as a standalone product.
## What it is
**Verifiable Audit Log** is a tamper-evident, post-quantum chain of business events. Append any event —
a payment decision, an admin action, a config change, a compliance verdict — and it is content-addressed
and recorded as a **Falcon-1024-signed** entry linked to the previous one. The result is an
**append-only log** anyone can verify offline: no entry can be **altered, inserted, removed, reordered,
or back-dated**.
It is the [Verifiable Archive](/verifiable-archive) chain generalised from *documents* to *arbitrary
events* — the event is recorded inline, so it's a lightweight, immutable system-of-record for anything
an auditor needs to trust.
Each entry is signed and hash-linked to the one before it. Any alteration, insertion, deletion,
reorder, or back-date breaks verification — and anyone can detect it from the public key.
Falcon-1024 signing means a record written now stays verifiable past the migration to post-quantum
cryptography — the right horizon for retained audit logs.
The event is an arbitrary JSON object, content-addressed and recorded inline — payments, decisions,
access events, config and state changes, compliance verdicts.
Verification is a pure function of the entries and the public key. Hand an auditor the log and the
key; they verify it themselves — no service, no vendor dependency.
## What you get
* **An audit trail you can prove.** A database audit table can be edited by whoever owns the database.
This chain is cryptographic — tampering is detectable by anyone, from the public key alone.
* **Vendor-independent verification.** No service to call at audit time. The log and the public key are
enough for a regulator or auditor to verify the whole history themselves.
* **Quantum-resistant retention.** Records kept for years — even decades — stay verifiable past the
post-quantum migration.
* **Record anything, lightweight.** Events are recorded inline; there's no blob store or encryption to
operate. A pluggable store persists where you already persist.
* **Optionally Substrate 2-bound.** Entries fold into the broader [Substrate 2](/substrate-2) evidence
chain alongside receipts and document evidence.
## How it works
| Step | What happens |
| --------------- | ------------------------------------------------------------------------------ |
| **Append** | Submit an event; it is content-addressed (`sha256` of its canonical form). |
| **Sign + link** | The entry is Falcon-signed and linked to the previous one (`prev_entry_hash`). |
| **Verify** | Check any entry — or the whole chain's integrity and ordering — offline. |
## Cryptography
* **Post-quantum signing + quantum-resistant chaining.** Each entry is signed with Falcon-1024
(NIST Level 5) and linked by a SHA-256 hash chain — both resistant to quantum attack — so the log
stays tamper-evident and verifiable into the post-quantum era.
* **Canonical form verified across 8 implementations.** Each event's signed preimage uses RFC 8785
(JCS) canonicalization — the discipline in AlgoVoi's open [conformance corpus](/conformance-vectors).
A real audit entry canonicalized byte-identically across eight independent JCS implementations
(Python, Node.js, Ruby, PHP, Go, Rust, Java, .NET), so the 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 and verifier 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,
provable record-keeping:
* **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 are ongoing work, bundled into the licence.
## Who it's for
* **Regulated fintech and VASP back-offices** that need an immutable, provable trail of payments,
decisions, and access events.
* **SOX-scoped and public-company systems** that need tamper-evident change and action logs an auditor
can verify independently.
* **Security teams** that want a log nobody — not even an attacker with database access — can alter undetected.
* Anyone who needs **a record an auditor or regulator can trust because nobody could have altered it**.
## Frequently asked questions
### What software provides tamper-evident, independently timestamped audit logs for AI systems?
AlgoVoi's Verifiable Audit Log records any system or business event — a model
decision, an admin action, a config change, a compliance verdict — as a
content-addressed, Falcon-1024-signed entry hash-linked to the one before it, so
no entry can be altered, inserted, removed, reordered, or back-dated undetectably.
Paired with [Records Vault](/records-vault) it adds RFC-3161 trusted timestamps
from an independent authority, so each record is bound to a time you did not
assert yourself. It is self-hosted and air-gap capable, and the whole chain
verifies offline from a published public key.
### How is this different from a database audit table?
A database audit table is writable by whoever owns the database, so its integrity
rests on trusting the operator. This chain is cryptographic: tampering with any
entry breaks verification at exactly that entry, and anyone holding the public key
can detect it. The proof is a mathematical check, not a matter of trusting your
process or your SIEM.
### Can an auditor verify the log without trusting the vendor?
Yes. Verification is a pure function of the entries and the published public key.
Hand an auditor or regulator the log and the key and they verify the whole history
themselves — no AlgoVoi account, no running service, no network call in the
verification path.
### Does a tamper-evident audit log help meet EU AI Act, MiCA or DORA logging duties?
It provides the integrity evidence those regimes point to. The
[EU AI Act record-keeping](/eu-ai-act-recordkeeping) duty (Articles 12, 19, 26),
[MiCA Article 68(9) and DORA](/mica-dora-evidence) logging (with CDR (EU)
2024/1774 Article 12 requiring log information to be protected against tampering
and deletion) all require records that cannot be silently rewritten. A
hash-linked, post-quantum-signed, offline-verifiable log answers the integrity
half of those obligations; your counsel certifies compliance on top of it.
## See also
* [Verifiable Compliance Suite](/verifiable-compliance-suite) -- the estate this component ships in.
* [Records Vault](/records-vault) -- adds RFC-3161 timestamping, read-access logging, and legal holds.
* [EU AI Act record-keeping](/eu-ai-act-recordkeeping) -- Articles 12/19/26 mapped to this evidence layer.
* [MiCA and DORA evidence](/mica-dora-evidence) -- MiCA Article 68(9) and DORA ICT-incident logging.
* [Verify it yourself](/verify-it-yourself) -- run the offline verifier against a real evidence pack.
## Get Verifiable Audit Log
Verifiable Audit Log ships inside the [Verifiable Compliance Suite](/verifiable-compliance-suite). One
commercial licence installs the whole compliance estate. It pairs with
[Verifiable Archive](/verifiable-archive) (documents) to form a complete verifiable evidence record. It
binds to Substrate 2 (it is not part of Substrate 2 itself), is included in the AlgoVoi Enterprise and
[On-premise](/on-premise) plans, and is not distributed on public package registries. Install is
token-gated from the AlgoVoi private index; set `ALGOVOI_LICENSE_KEY` to run. See the
[Verifiable Compliance Suite](/verifiable-compliance-suite) for licensing, or
[email us](mailto:hello@algovoi.co.uk) for Enterprise / OEM.