CernBankSign inEffective September 26, 2026
Privacy Policy
CernBank is self-custody software for the xCoin (XID) network. It is built so that we never hold your money and never see the keys that control it. This policy explains the small amount of information we do handle, and why.
What we never receive
- Your wallet seed, your .mmm file, your .mmm passphrase or any private key.
- Your device PIN, or anything from your passkey that could unlock your wallet.
- Your Google password. Google confirms who you are; we never see your password.
When you import a wallet, it is opened and encrypted in your own browser with AES-256. We receive only that encrypted result, which we call garbage, because that is all it is to anyone without your device: unreadable to us, to anyone who breaks into our systems, and to quantum computers.
What we store
| Information | Why |
|---|---|
| Your name, email address and profile picture from Google, and Google's account identifier | To sign you in and show you your account. |
| Your encrypted wallet (garbage) and the passkey-wrapped keys for it | So you can unlock your wallet on your devices. We cannot open it. |
| Your account addresses (public xCoin addresses) and the names you give your accounts | To show balances and statements. Addresses are public on the xCoin blockchain. |
| Payees you save, and records of transfers you send through CernBank, including any private note | To show your activity and statements. |
| Sign-in sessions and a security log (time, device type, country) | To protect your account and show you where you are signed in. |
| Your settings (auto-lock time, large-transfer threshold, hidden balances) | To apply your preferences. |
Your device PIN, when you set one, is kept only in your browser's storage on that device.
How information travels
Everything is sent over HTTPS with post-quantum key exchange, and every CernBank request is additionally sealed with ML-KEM-768 and AES-256-GCM inside that connection. Balances, network fees and transaction broadcasts are read from and sent to the public xCoin explorer at superknet.com directly from your browser; those requests contain only public blockchain data.
What we do not do
- We do not sell, rent or trade your information.
- We do not use advertising or tracking cookies. The only cookies are for keeping you signed in and securing sign-in.
- We do not use your Google data for anything other than signing you in, and we do not share it.
Who helps us run CernBank
Cloudflare hosts CernBank and its database. Google provides sign-in. They process information only to provide those services.
Keeping and deleting information
We keep your information while your account is open. You can close your account at any time in Settings; this deletes your profile, encrypted wallets, payees, transfer records, sessions and security log from CernBank. Your coins are not affected: they remain on the xCoin blockchain and open with your .mmm file or seed in any xCoin wallet. Transactions already on the blockchain are public and permanent, and no one can delete them.
Your choices and rights
You can see and change your information in the app, download statements, remove wallets and payees, and close your account. For anything else, including a copy of your data or a correction, email support@cernbank.com. Depending on where you live, you may have additional rights under local privacy law, and we will honor them.
Children
CernBank is not for anyone under 18.
Changes
If we change this policy, we will update the date above and tell you in the app before significant changes take effect.
Contact
Questions: support@cernbank.com. We will never ask for your seed, passphrase or PIN.