It is guaranteed to never disclose the private key. Handing a Card over, is by nature, an off-chain payment transaction. One can sell it as merchandise, send it as a gift, or use it to make a payment. Essentially, it's a secure, smart note for digital assets.

A Tangem Card is a durable plastic card with only one element. This element is a secure chip that holds the funds and the private key. The chip has the NFC antenna that allows you to check the balance and transfer your funds with an NFC-enabled phone.

At the moment, Tangem supports the following cryptocurrencies: BTC, ETH, XRP, BCH, XLM, ADA.

In order to optimize for user experience, we kept it simple. Each Tangem Card is fixed to a certain cryptocurrency and can hold one private key at a time.

If you want to order custom cards, please contact us via email: sales@tangem.com

Online: order unloaded cards at Tangem online store https://shop.tangem.com

Worldwide courier shipping.

We accept all major credit cards and crypto currencies.

As of today, we offer transparent BTC, ETH, BCH, XRP, XLM Cards in our Bird Collection design. ETC and BTC are available in the Original Collection.

Tangem produces graphically customized cards, configured to carry specific assets like ERC-20 or simply just BTC. For example, check out Digix and SwissKey.

If you want to order custom cards, please contact us via email: sales@tangem.com

For Android devices:

• Download Tangem in the Google Play Store here.

• Tap a Tangem Card on your phone's NFC reader (tap the Card the same way you use your Google Pay) and you’ll automatically be redirected to the Google Play Store.

For iOS devices

• Download Tangem in the App Store here.

If you have ever used Apple or Google Pay, you know exactly how to check the value of a Tangem Card and the amount of funds it’s holding. You just need to open the Tangem app (available on the Google Play store here, or the Tangem app for iOS, available here) and tap the Card to the NFC scanner inside your phone.

Scanning the Card only takes a few seconds. The app will verify that the Card is genuine, ensure it possesses the correct private key, and obtain the balance from the blockchain. You can always double check your balance directly in the blockchain explorer if needed. From this point, you can rest assured that you are the only holder of the private key and the funds on the Card.

Once the Card is scanned and verified, the app will display the exact blockchain address linked to the Card. You can use any other blockchain wallet app to transfer funds to the Card from a source wallet. You can also transfer funds from another Card using the Tangem app.

To extract funds from a Tangem Card, you will need a Tangem Card, along with the Tangem app on an NFC-enabled device.

Scan and verify the Card through the Tangem app, then tap the ‘Extract’ button and prepare the outgoing transaction:

• Define the target wallet address

• Set the amount of funds to transfer

• Accept the transfer fee

You will be asked to tap and hold the Card while it signs the transaction. In the end, the signed transaction will be broadcasted to the blockchain.

That’s all!

Please note: As the functionality of the NFC in the iOS 12 and below is limited to read-only, sending data is not allowed. This means that you can check the validity of the Card and any funds it’s holding. You can load or extract them using iPhones with iOS 13.

Tangem Cards are fully reusable. There is no limit for transactions or for how many times you perform loading/extraction operations.

Tangem Cards are limitless. You can send as many funds to your Tangem Card as you want.

Before transferring a substantial amount of assets to self custody, we recommend seeking professional advice regarding portfolio allocation and other saving practices.

We know it’s a little disappointing that you can only check the validity of the Card with your iPhone. But the functionality of our Tangem app totally depends on the iOS NFC functionality. iOS 12 and below limits NFC functionality to read-only, so sending data is not allowed.

You can neither import the private key into a Tangem Card nor export the private key -- so it’s completely impossible to have a copy. The architecture of each Tangem Card guarantees the chip inside is the only place in the universe where the unique key can ever be located.

The security of Tangem technology is audited by the Kudelski Group, a listed Swiss security company. The report is available here.

After the audit, the chip firmware cannot be modified even by Tangem. Its intactness in each Card can be verified with the Tangem App. The app and the NFC communication protocol are open source.

Not to worry - nobody will be able to transfer funds from your Card just by scanning it. Although checking the funds takes seconds, transferring them requires you to hold the Card against your phone for 15-30 seconds.

This is a security measure, its duration is configurable and it can be overridden by enabling a PIN-code on the Card (available on demand).

As with traditional banknotes, a Tangem Card has to be kept physically secure at all times. The whole cryptocurrency value is always solely represented by the chip inside, hence cannot be accessed without the Card.

If you lose a Tangem Card, you lose the assets. That’s why we don’t recommend loading a large amount of funds to the Card.

The electronics inside Tangem Cards are designed to have incredible resilience against attacks and wear. On top of that, every single Card undergoes comprehensive testing during and after manufacturing.

Every time you validate a Tangem Card, it checks the internal consistency. It will ask you to extract its value at the slightest suspicion of something going wrong.

While Tangem makes no further warranties, you can mail your Tangem Card to our offices around the world. If our labs are able to extract the value or determine that there was a loss of value due to an unknown manufacturing defect, we’ll work with you directly on a case by case basis.

As a company, Tangem is purely a hardware technology vendor and does not hold or operate any cryptocurrency. Loading assets in Tangem Cards is done entirely by third parties like exchanges, wallets, custodial services, etc.

A wallet private key, which is the key to the ownership of blockchain assets, is always securely generated inside the Tangem chip. The key cannot be injected from outside, backed up or restored. Thus, the card holds a unique and unclonable instance of the wallet.

A holder of a Tangem card doesn’t have to worry about the card’s history or trust previous owners. Once the Blockchain is validated with the Tangem mobile app, there is a 100% guarantee that the holder of the card exclusively owns the corresponding Blockchain asset.

Each Tangem card stores a unique authentication key that can be verified with Tangem Authentication Service to make sure the card is genuine and was manufactured by Tangem. This service is anonymous and optional. Tangem mobile apps will alert the user if the card is unknown to Tangem.

The card’s firmware is constant. The integrity of the whole card’s binary code can be validated directly with the Tangem mobile apps against a code footprint generated by an independent security auditor. This type of end-to-end code validation mechanism guarantees that no single card has been tampered with and that no changes have been made, even by Tangem.

Every Tangem card can be protected with a user-defined password. Even without a password, the card will effectively protect itself from drive-by attacks by requiring the user to hold the card against the phone for a significant amount of time.

The NFC communication channel between the card and the phone is encrypted and tamper-proof.

Funds are always under the full control of the card holder. Tangem does not process incoming or outgoing transactions, and does not operate its own trusted nodes. Our open source mobile apps communicate directly with a random open Blockchain node to obtain a wallet balance and broadcast transactions. Advanced users can fine-tune nodes according to their preferences.

Smart-card technology dictates a “security through obscurity” approach. Disclosure of the source code within secure elements would render hardware wallets vulnerable. In order to prove that Tangem firmware has no backdoors or bugs that would lead to loss of funds, Tangem has employed a renowned independent security auditor, Kudelski Security. The results of the audit are here:

https://research.kudelskisecurity.com/2018/08/06/audit-of-tangems-smartcard-wallet-code/amp/

Tangem firmware works on a native microcontroller level and does not rely on non-transparent platforms, such as third-party implementations of JavaCard VM. There are also no mechanisms to remotely control or update the firmware after the card is manufactured.

Since usage of the genuine Tangem mobile apps is crucial for safety, we encourage users to install and use only official Tangem apps from app stores. Avoid using third-party apps or installing Tangem apps from untrusted sources unless they are approved by Tangem

Like other high-grade hardware wallets with secure screens and buttons, high-value Tangem cards provide optional two-factor authorization of transactions through secure channels.

Tangem does not monitor incoming or outgoing transactions. We never gather wallet addresses, personal data of users, or any other kind of information which can identify users or users’ phones. A Tangem card is a self-sufficient, complete bearer instrument, like a paper banknote.

Simple and durable card construction: the chip is protected against impact and the environment by a solid hermetic package and three layers of plastic. The chip carries the most advanced protected flash memory, providing the maximum possible data retention time — up to 50 years at room temperature.

Tangem guarantees compensation of lost funds if the loss was caused by a card’s failure. Our compensation policy is described in the Terms of Use.

No cards manufactured by Tangem depend on any special infrastructure, or on Tangem as a company. In an emergency situation — for example, if Tangem apps were removed from app stores — any trusted application supporting Tangem NFC protocols could be used to sign and broadcast transactions.