What is a cold wallet – and why self-custody matters

Keys, not coins

A wallet does not store coins. Coins exist on the blockchain; the wallet stores the private key that allows you to move them. Whoever holds the private key controls the assets. That is why the first rule of digital assets is: never share your private key or seed phrase with anyone.

Hot and cold

A hot wallet is software on a device connected to the internet – a phone app or browser extension. It is convenient but exposed to malware and phishing. A cold wallet keeps the private key on a device that is never directly online; transactions are signed on the device and only the signed result is sent to the network. Hardware wallets are the most common form of cold storage.

Self-custody versus exchange

If your assets sit on an exchange, the exchange holds the keys and you hold a claim against the exchange. If the exchange fails or freezes withdrawals, your claim may be worth little. Self-custody means you hold the keys yourself – with full control and full responsibility: lose the key and the backup, and the assets are gone.

The Novaro x Tangem card

Tangem is a Swiss-based maker of card-shaped cold wallets. The private key is generated on a certified chip inside the card and never leaves it; you approve transactions by tapping the card on your phone. Tangem cards work without battery and, depending on the setup, without a seed phrase, using backup cards instead.

The Novaro x Tangem card is a limited edition of this product with Novaro branding, sold by Tangem on its own page novaro.tangem.com. Novaro does not have access to the keys on the card. Purchases and support are handled by Tangem under its own terms.

Practical rules

Write down or back up your recovery information offline and store it in two separate places. Test a small transaction before moving larger amounts. Verify addresses character by character. Be suspicious of anyone who offers to "help" with your wallet – legitimate support will never ask for your key.