# Contubernium Verification License

**Version 1.0. Quantum Ridge Systems, Inc. may post revised versions; each copy of the
Software is governed by the license version posted when that copy was obtained.**

Copyright © 2026 Quantum Ridge Systems, Inc. All rights reserved.

This license makes the published Contubernium verification code **source-available, not
open source**. You can read every line, check every receipt, and run a witness — that
openness is what makes the record trustworthy. What is *not* granted is the right to take
this code into other products or competing services. The rule of the system is the rule of
the license: checking is free forever; everything else is reserved.

## 1. Definitions

**"Software"** means the source code, scripts, and files published by Quantum Ridge
Systems, Inc. in the Contubernium source archive and artifact set at contubernium.io,
excluding the Specification and the Conformance Vectors defined below.

**"Specification"** means the published Contubernium specification document.

**"Conformance Vectors"** means the published test-vector files.

**"Verification Purposes"** means, and is limited to:

(a) verifying Contubernium receipts, checkpoints, proofs, and records, or the conduct of
any party producing them;

(b) operating a witness against a Contubernium transparency log;

(c) testing an implementation of the Specification against the Conformance Vectors; and

(d) security review, audit, and analysis of any of the foregoing.

## 2. Grant

Subject to the conditions and restrictions below, Quantum Ridge Systems, Inc. grants you a
worldwide, royalty-free, non-exclusive, non-transferable, non-sublicensable right to use,
reproduce, and modify the Software **solely for Verification Purposes**.

## 3. Conditions

(a) You must retain all copyright and license notices in all copies and modifications.

(b) You may redistribute the Software, modified or unmodified, only for Verification
Purposes and only with this license attached.

## 4. Restrictions

Except as expressly granted in Section 2, all rights are reserved. Without limiting that
reservation, this license does **not** permit you to:

(a) use the Software to provide, operate, or assist a product or service that competes
with any product or service of Quantum Ridge Systems, Inc.;

(b) incorporate the Software, in whole or in part, into any other software or product;

(c) sublicense the Software or offer it to others on different terms; or

(d) use the name "Contubernium," the Contubernium marks, or the name of Quantum Ridge
Systems, Inc., except to accurately identify unmodified copies of the Software or to state
factually that an independent implementation was tested against the Conformance Vectors.
No trademark rights are granted.

## 5. The Specification and the Conformance Vectors

Independent implementation of the Specification is not restricted by this license, which
covers this code, not the method it implements. You may use the Conformance Vectors to
test any implementation. An implementation written by you from the Specification is yours;
this license neither grants rights in it nor claims any.

## 6. Termination

This license terminates automatically upon breach. Upon termination you must cease all use
and destroy all copies, except that verifications already performed remain valid.

## 7. No warranty

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL QUANTUM RIDGE SYSTEMS, INC. BE LIABLE FOR
ANY CLAIM, DAMAGES OR OTHER LIABILITY ARISING FROM OR IN CONNECTION WITH THE SOFTWARE OR
ITS USE.