What Is the Vault Key Card?
The Vault Key Card (VKC) is Zypto's card-based cold storage solution. It's a physical NFC card that secures your crypto wallets by splitting your private key between two places, keeping your wallet truly offline until you need it.
For a deeper dive into how card-based cold storage works and how the VKC compares to other hardware wallets, check out our VKC Guides and Cold Storage Hub on the Zypto blog.
How It Actually Works
When you link the VKC to a wallet, the wallet's private key is split into two encrypted parts. One part is stored on your device, the other on the VKC card. Neither part is enough on its own to recover or reconstruct the private key.
This means your wallet is completely offline. No one can access it from just your phone, and no one can access it from just the card. The private key doesn't exist in complete form on either element.
When you need to sign a transaction, you tap the VKC against your phone. The two halves of the private key are temporarily recombined, bringing the wallet online just long enough to authorize the transaction. Once signed, the complete key is cleared from the device, and the wallet goes back to being fully offline. No transactions can be signed without physical possession of the card.
Important: The VKC Does Not Back Up Your Keys
The VKC is a security tool, not a backup tool. It does not store a copy of your seed phrase or full private key. The card only holds one encrypted half of the split key.
You must still securely store your seed phrase separately. Write it down and keep it somewhere safe. If you ever need to unlink, format, or replace your VKC, you will need your seed phrase or private key to restore access to your wallet. Without it, there is no way to recover your funds.
This is true of all cold storage solutions: the VKC protects your wallet from unauthorized use, but your seed phrase is your ultimate recovery method. Never lose it, never share it.
Key Advantages
Secures wallets you already have: Unlike many hardware wallet solutions that require you to create new wallets, the VKC can be linked to any existing wallet in your Zypto app.
Protects up to 3 wallets: A single VKC can be linked to up to 3 wallets at once.
Flexible protection: You can unlink wallets and link different ones, so you can change which wallets are protected as your needs evolve.
All chains supported: The VKC secures all blockchain networks currently supported on the Zypto app, not just one chain.
No extra device to carry: It's the size of a credit card and fits in your regular wallet. No USB cables, no charging, no separate screens.
Setting Up Your Vault Key Card
What you need:
The Zypto app installed and updated to the latest version
A DeFi wallet already created or imported in the app
Your Vault Key Card (the physical NFC card)
A phone with NFC capability (most modern smartphones have this)
There are two ways to link the VKC to a wallet:
Option A: From the home screen
On the Zypto app home screen, find the VKC management section.
Select the option to link a wallet.
Choose which wallet you want to protect.
When prompted, hold the VKC against the NFC reader area of your phone (usually the back, near the top). Keep the card steady until the app confirms the connection.
The app will split and encrypt your private key, storing one half on the device and one half on the card. Your wallet is now in cold storage.
Option B: From within a wallet
Open the wallet you want to protect.
Tap the three-dot menu in the top right corner of your wallet view.
Select "Vault Key Card" or "Link VKC".
Follow the on-screen prompts and tap the VKC when asked.
Once confirmed, the wallet is now VKC-protected.
NFC tips: On iPhone, NFC is always on. On Android, check that NFC is enabled in your phone settings. If the tap isn't registering, try removing your phone case and repositioning the card on the back of your phone. The NFC antenna location varies by device.
You can repeat this process for up to 3 wallets per VKC.
Using the VKC for Transactions
Once linked, any outgoing transaction from a VKC-protected wallet requires a physical card tap. When you initiate a send, swap, or other outgoing transaction:
The app will prompt you to tap the VKC
Hold the card against the NFC area of your phone
The private key is temporarily recombined to sign the transaction
Once signed, the key is cleared and the wallet returns to offline mode
You don't need the VKC for everything. Viewing balances, checking transaction history, receiving crypto, and browsing the app all work without it. The VKC is specifically required for authorizing outgoing transactions from wallets it's linked to.
Unlinking and Formatting
You can unlink the VKC from a wallet through the wallet settings or the VKC management section on the home screen. Once unlinked, the full private key is restored to the device and the wallet operates normally without cold storage protection.
There may be situations where you need to unlink or format the card (for example, to reassign it to different wallets or troubleshoot an issue). Always make sure you have your seed phrase or private key backed up before unlinking or formatting. You will need it to restore access to your wallet if anything goes wrong during the process.
If the in-app unlink option isn't working (for example, if you see a "No password found" error), contact support and the team can assist with unlinking on the backend.
Troubleshooting
NFC tap isn't being recognized
Make sure NFC is enabled in your phone settings
Remove any phone case that might be blocking the NFC signal
Try positioning the card in different spots on the back of your phone (the NFC antenna location varies by device)
Keep the card steady for a few seconds rather than just tapping quickly
Transaction not completing after tapping the card
If the app recognizes the card but the transaction doesn't go through, try closing and reopening the app, then attempt the transaction again. If the issue persists, contact support with details of the transaction you're trying to make.
"No password found" error when trying to unlink
This is a known issue that can occur in some cases. Contact support and the team can assist with unlinking the VKC from your wallet on the backend. Make sure you have your seed phrase ready in case a wallet reimport is needed.
What Happens If You Lose the VKC?
Losing the VKC does not mean losing access to your crypto. Your assets are on the blockchain, and as long as you have your seed phrase, you can always recover your wallets. If you lose the VKC:
Contact support to have the VKC unlinked from your wallet
You may need to reimport your wallet using your seed phrase
Once restored, your wallet will work normally without VKC protection
You can order a replacement VKC and link it again
This is why backing up your seed phrase is essential. The VKC adds a layer of security on top of your existing wallet, but your seed phrase remains your ultimate recovery tool.
VKC Shipping and Delivery
The VKC is shipped internationally via courier (UPS/DHL). A few things to be aware of:
Customs/tariff charges: Depending on your country, you may be asked to pay a customs tariff on delivery. This is a charge from the courier/customs authority, not from Zypto. Tariff amounts vary by region.
Tracking: You'll receive a tracking number via email after your order ships. If tracking isn't updating, give it 24-48 hours as carrier systems can sometimes lag behind.
Who Is the VKC For?
The VKC is ideal for users who hold meaningful amounts of crypto and want hardware-level security without carrying a separate device. If you're used to hardware wallets like Ledger or Trezor but want something that fits in your regular wallet and works with wallets you already have, the VKC is a strong option.
If you're new to crypto or only hold small amounts, the standard app-level security (passcode + biometrics) is sufficient. You can always add a VKC later as your holdings grow.
For the full set of guides on VKC and card-based cold storage, visit our VKC Guides Hub on the Zypto blog.
Questions about the VKC? Our support team is available 24/7 in most regions to help.