Terms of Service

Last Updated: October 20, 2026

Agreement to Terms

By downloading, installing, or using Arké ("the App"), you agree to be bound by these Terms of Service ("Terms"). If you do not agree to these Terms, do not use the App.

Description of Service

Arké is a self-custodial Bitcoin wallet application that implements the Ark protocol. The App provides software that allows you to:

Generate and manage Bitcoin wallets
Send and receive Bitcoin
Interact with the Ark protocol for Bitcoin transactions
Store wallet data securely on your device using Apple Keychain and iCloud

To make payments from your payments balance, the App connects to an Ark server operated by TwoND, Inc., doing business as Second ("Second"). We do not operate or control this server. By using the App's payments balance, you also agree to Second's Terms of Service, which govern your use of their server. Second's terms are a separate agreement between you and Second. Among other things, they allow Second to change or stop its service, to restrict access, and to claim bitcoin in expired VTXOs (see Risks below).

Experimental Software

The App is experimental. It is built on a young protocol and is under active development. Features may change or be removed, and the App may contain bugs that affect your funds. Only use amounts you can afford to lose.

We may stop developing or distributing the App at any time. Because the App is self-custodial, you can withdraw your bitcoin to the Bitcoin main chain without our involvement, as described in these Terms.

Self-Custody and Your Responsibilities

You Control Your Wallet

This is a self-custodial wallet. This means:

You alone control your private keys and recovery phrase
We never have access to your private keys, recovery phrase, or funds
We cannot freeze, seize, or control your Bitcoin in any way
We cannot reverse, cancel, or modify any transactions you make
We cannot recover your wallet if you lose your recovery phrase

Your Responsibilities

By using the App, you acknowledge and agree that you are solely responsible for:

Securing your recovery phrase — Write it down and store it in a safe, offline location. Anyone with access to your recovery phrase can access your funds.
Securing your device — Use a strong passcode, enable biometric authentication, and keep your device's operating system updated.
Securing your Apple ID — Your iCloud backup (if enabled) is protected by your Apple ID. Use a strong password and enable two-factor authentication.
Maintaining backups — Ensure you have a secure backup before storing any significant value. A full backup consists of your recovery phrase and your backup file (or an iCloud backup). Your recovery phrase alone may recover your bitcoin but not your transaction history.
Verifying transaction details — Always verify recipient addresses and amounts before confirming transactions. Bitcoin transactions are irreversible.
Understanding the technology — You are responsible for understanding how Bitcoin, the Ark protocol, and self-custodial wallets work.

No Recovery Possible

IMPORTANT: If you lose your recovery phrase, lose access to your device, and have no iCloud backup, your Bitcoin will be permanently lost. We have no ability to recover your funds under any circumstances. There is no "forgot password" option.

Notifications

Payment notifications are optional and provided on a best-effort basis. iOS may delay or limit them, apps that were force-quit may not be woken, and outages at Apple, the Ark server, or our relay can delay or drop them. Don't rely on notifications to learn about payments. Visible notifications may show payment amounts on your lock screen. We may change or stop the notification service at any time. See our Privacy Policy for what the relay processes.

Risks

Cryptocurrency Risks

You acknowledge that:

Price volatility — The value of Bitcoin can fluctuate dramatically. You may lose some or all of the value of your holdings.
Regulatory uncertainty — Cryptocurrency regulations vary by jurisdiction and may change. You are responsible for compliance with applicable laws.
Technical risks — Software may contain bugs. While we strive for quality, no software is perfect.
Network risks — The Bitcoin network and Ark protocol operate independently of us. Network congestion, protocol changes, or failures could affect your ability to transact.
Irreversibility — Bitcoin transactions cannot be reversed. If you send Bitcoin to the wrong address, it may be permanently lost.

Ark Protocol Risks

The Ark protocol involves specific considerations:

Ark is a relatively new protocol and may have undiscovered vulnerabilities
The App currently relies on a single Ark server, operated by Second. If it is unavailable, you cannot make payments from your payments balance until it returns, or until you withdraw to the Bitcoin main chain
Payments made before the next round depend on the Ark server not colluding with the sender
VTXO expiry: Funds in your payments balance are held in VTXOs that expire. The App refreshes them automatically when you open it. If a VTXO expires without being refreshed or withdrawn, for example because you did not open the App for an extended period, Second's terms allow it to claim the bitcoin in it, with no obligation to return it
Protocol upgrades or changes could affect functionality
Liquidity and availability of Ark services may vary, and Second may restrict access in some jurisdictions

No Investment Advice

Nothing in the App or these Terms constitutes financial, investment, legal, or tax advice. Consult qualified professionals before making financial decisions.

Prohibited Uses

You agree not to use the App to:

Violate any applicable laws or regulations
Engage in money laundering, terrorist financing, or other illegal activities
Defraud or attempt to defraud any person or entity
Interfere with or disrupt the App or any connected networks
Reverse engineer, decompile, or disassemble the App except as permitted by law
Use the App in any jurisdiction where such use is prohibited

Intellectual Property

The App and its original content, features, and functionality are owned by GBKS limited and are protected by international copyright, trademark, and other intellectual property laws.

Open Source Components

The App may include open source software components, which are subject to their respective licenses. A list of open source components and their licenses is available at this link.

Disclaimer of Warranties

THE APP IS PROVIDED "AS IS" AND "AS AVAILABLE" WITHOUT WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO:

IMPLIED WARRANTIES OF MERCHANTABILITY
FITNESS FOR A PARTICULAR PURPOSE
NON-INFRINGEMENT
THAT THE APP WILL BE UNINTERRUPTED, SECURE, OR ERROR-FREE
THAT DEFECTS WILL BE CORRECTED
THAT THE APP IS FREE OF VIRUSES OR OTHER HARMFUL COMPONENTS

YOU USE THE APP AT YOUR OWN RISK. WE DO NOT WARRANT OR GUARANTEE THE SECURITY OF YOUR BITCOIN OR THE RELIABILITY OF ANY TRANSACTION.

Limitation of Liability

TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, IN NO EVENT SHALL GBKS LIMITED, ITS DIRECTORS, EMPLOYEES, PARTNERS, AGENTS, SUPPLIERS, OR AFFILIATES BE LIABLE FOR:

ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES
ANY LOSS OF PROFITS, REVENUE, DATA, OR USE
ANY LOSS OF OR DAMAGE TO YOUR BITCOIN OR OTHER CRYPTOCURRENCY
ANY LOSS ARISING FROM YOUR FAILURE TO SECURE YOUR RECOVERY PHRASE
ANY LOSS ARISING FROM UNAUTHORIZED ACCESS TO YOUR DEVICE OR ACCOUNTS
ANY LOSS ARISING FROM ERRORS IN TRANSACTION DETAILS YOU PROVIDED
ANY LOSS ARISING FROM THE OPERATION OF THE BITCOIN NETWORK OR ARK PROTOCOL

WHETHER BASED ON WARRANTY, CONTRACT, TORT, OR ANY OTHER LEGAL THEORY, AND WHETHER OR NOT WE HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

IN JURISDICTIONS THAT DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY, OUR LIABILITY SHALL BE LIMITED TO THE GREATEST EXTENT PERMITTED BY LAW.

Indemnification

You agree to indemnify, defend, and hold harmless GBKS limited and its officers, directors, employees, agents, and affiliates from any claims, damages, losses, liabilities, and expenses (including reasonable legal fees) arising from:

Your use of the App
Your violation of these Terms
Your violation of any third-party rights
Your violation of any applicable laws

Updates to the App

We may update the App from time to time. While we will strive to maintain compatibility, updates may change functionality. You are responsible for keeping your App updated.

Changes to Terms

We reserve the right to modify these Terms at any time. We will notify you of material changes by updating the "Last Updated" date and, where appropriate, providing notice within the App. Your continued use of the App after changes constitutes acceptance of the new Terms.

Termination

You may stop using the App at any time. We may terminate or suspend your access to the App immediately, without notice, for conduct that we believe violates these Terms or is harmful to other users, us, or third parties.

Upon termination, your right to use the App ceases immediately. However, because this is a self-custodial wallet, your Bitcoin and recovery phrase remain yours. You can withdraw your payments balance to the Bitcoin main chain, and you can use your recovery phrase to access your savings balance through any compatible wallet software.

Governing Law

These Terms shall be governed by and construed in accordance with the laws of Germany, without regard to its conflict of law provisions.

Dispute Resolution

Any disputes arising from these Terms or your use of the App shall be resolved through binding arbitration in accordance with the rules of Germany, except that either party may seek injunctive relief in any court of competent jurisdiction.

Severability

If any provision of these Terms is found to be unenforceable, the remaining provisions shall remain in full force and effect.

Entire Agreement

These Terms, together with our Privacy Policy, constitute the entire agreement between you and GBKS limited regarding the App. Your use of Second's Ark server is governed separately by Second's Terms of Service.

Contact

If you have questions about these Terms, please contact us at:

knueffelbund@gmail.com

Acknowledgment

BY USING THE APP, YOU ACKNOWLEDGE THAT YOU HAVE READ THESE TERMS, UNDERSTAND THEM, AND AGREE TO BE BOUND BY THEM. YOU ALSO ACKNOWLEDGE THAT YOU UNDERSTAND THE RISKS ASSOCIATED WITH SELF-CUSTODIAL CRYPTOCURRENCY WALLETS AND ACCEPT FULL RESPONSIBILITY FOR SECURING YOUR RECOVERY PHRASE AND FUNDS.

How it works.