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CoinCorner Bolt Card

🔍 Last analysed 25th November 2022 . Bad Interface

The design of the device does not allow to verify what is being signed!

As part of our Methodology, we ask:

Can the user verify and approve transactions on the device?

If the answer is "no", we mark it as "Bad Interface".

These are devices that might generate secure private key material, outside the reach of the provider but that do not have the means to let the user verify transactions on the device itself. This verdict includes screen-less smart cards or USB-dongles.

The wallet lacks either an output device such as a screen, an input device such as touch or physical buttons or both. In consequence, crucial elements of approving transactions is being delegated to other hardware such as a general purpose PC or phone which defeats the purpose of a hardware wallet.

Another consquence of a missing screen is that the user is faced with the dilemma of either not making a backup or having to pass the backup through an insecure device for display or storage.

The software of the device might be perfect but this device cannot be recommended due to this fundamental flaw.

The product cannot be independently verified. If the provider puts your funds at risk on purpose or by accident, you will probably not know about the issue before people start losing money. If the provider is more criminally inclined he might have collected all the backups of all the wallets, ready to be emptied at the press of a button. The product might have a formidable track record but out of distress or change in management turns out to be evil from some point on, with nobody outside ever knowing before it is too late.

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Do your own research!

Try out searching for "lost bitcoins", "stole my money" or "scammers" together with the wallet's name, even if you think the wallet is generally trustworthy. For all the bigger wallets you will find accusations. Make sure you understand why they were made and if you are comfortable with the provider's reaction.

If you find something we should include, you can create an issue or edit this analysis yourself and create a merge request for your changes.

The Analysis 

Updated Review 2022-11-25

Bolt Card is now available for purchase. CoinCorner’s homepage describes it as a physical card that you can tap to pay via Lightning in person or on a website on your phone.

Features

  • Lightning payments
  • NFC/Contactless
  • Send BTC payments, funded from any currency
  • Easy setup via CoinCorner app
  • Use as a Gift Card to give BTC to a friend

Notably this device does not appear to have any display or button interface.

Here is a video demonstration from Coin Corner’s YouTube channel.

It is designed to pull money from the users CoinCorner account, turn it into Bitcoin, and send the Bitcoin to a merchant. Unfortunately, the card does not display the address or the amount of sats in a transaction.

From one of the YouTube comments:

The process looks too easy. At what point after the tap do I confirm the amount of SATs to be transferred? I would prefer a slightly more complex flow where the card has a little screen that displays the merchant’s invoice, with SATs to be approved, then I can approve and tap again.

The reply from CoinCorner:

Like any POS device, you can check the amount (displayed on screen) before you tap đź‘Ť

This means that the device depends on the merchant’s payment terminal.

Old Review

From the FAQ on the official Coin Corner website:

How does The Bolt Card work? </ br> Using a standard NFC card, the Bitcoin Lightning Network and LNURL, The Bolt Card enables a user to simply tap their card on a point of sale device displaying a Lightning invoice and the Lightning payment is made in the background. This transaction is carried out over the Bitcoin Lightning Network with not a single legacy payment system used.

The Bolt Card can communicate with point of sale devices via NFC. It is also compatible with protocols such as Lightning and LNURL.

Background

The CoinCorner Bolt Card was given away as a part of its marketing drive in the lead-up to the Advancing Bitcoin conference held in March of 2022 in London. It cannot be purchased from the site yet however you can find it in the Terms and Conditions of Coincorner.com.

Lightning Network transactions can be completed using the CoinCorner web platform, app, and “The Bolt Card” (an NFC enabled physical card) Completion of transactions on the Lightning Network are subject to channel and liquidity availability.

Analysis

As there is no official release date yet, much of the information about the card can be found through various sources:



What is clear is that the CoinCorner Bolt Card is an NFC-enabled Lightning Network payment medium.

We’ll update this once it has officially been released.

(dg)