How Backup Works
This article applies only to Tangem Hardware Wallets.
Using Mobile Wallet? See the Mobile Wallet Help Center.
Why do I need 2-3 Tangem devices?
Additional devices are needed to create backups. The number of cards or rings in your backup (2 or 3) determines how many copies of your private key exist. If one is lost or stolen, backup devices will help retain access to your funds.
Is there a difference between "primary" and "backup" devices?
No, all Tangem devices in the box are equivalent to each other and provide equal access to a single wallet.
How is a private key cloned into the backup devices?
When creating a backup, a secure communication channel is established between the Tangem devices using the Diffie-Hellman protocol, after which the keys are transferred from one device to another.
This mechanism is entirely protected from Man-in-the-Middle attacks because the initial stage of the cards involves authenticating each other with two-way authentication. The encryption is carried out using a 256-bit key. The encryption strength is at its maximum, and the app cannot decrypt the keys.
Learn more about creating a backup in our blog article: How to backup a private key in Tangem Wallet.
Why can I only create a backup once?
For security purposes, you can back up and clone a private key only once. This ensures that you have the correct number of copies of your private key.
Since the devices operate independently of the company's servers and are unaware of each other, creating a backup requires copying the private key to only the chosen number of devices (2 or 3).
If backup devices could be added multiple times, an attacker could make copies of your key without your knowledge.
Can I set up a wallet without an internet connection?
Yes. You can complete the wallet setup and backup offline, but each card or ring must first be scanned once while your device is connected to the internet.
During the first scan, the app downloads the device certificate required for end-to-end authentication. This allows the app to verify that Tangem made the wallet and that it is running Tangem firmware.
Once every card or ring in the set has been scanned online, you can turn off your internet connection or enable airplane mode and complete the setup offline.
This verification is also required to establish a secure communication channel between Tangem devices using the Diffie-Hellman key exchange protocol during backup.
Learn more about this process in our article: How to backup a private key in Tangem Wallet.
Important: This information is valid for the second-generation Tangem Wallets or later.
Can I add a third device later if I initially backed up on two devices?
For security reasons, the private key can only be backed up and cloned once. Therefore, when creating your wallet, you need to be certain about the number of devices you want to add.
If you want to add a third device to an existing wallet, you must reset the wallet to factory settings and create a new one with all three.
Before resetting your wallet to factory settings, move all cryptocurrencies stored in it to another location (such as another wallet or exchange) for a while. This is important because a reset completely erases all funds stored in the wallet.
To reset the entire wallet, you must repeat the reset steps for each device from the backup. Our blog provides detailed instructions: How to reset Tangem Wallet to factory settings.
