ColdCard Wallet

ColdCard is another Bitcoin hardware wallet developed by a team in Canada, its used to sign transactions and can be used both online and offline, it runs PSBTs natively so it can run completely offline for its entire lifecycle.

It works with major wallets like Electrum, uses standard PSBT transactions stored on a MicroSD chip and has a simple plain design with nothing much that can go wrong, it features a full-sized numeric keypad with a large 128x64 OLED screen and that is pretty much it for interface. It uses open source software design that runs Micropython allowing you to change it, its firmware is also open-sourced and available on Github.

ColdCard features several new security measures like the “Duress” wallet, duress wallet is a secondary fake wallet that should protect your Bitcoin in case of a physical attack on you, instead of you telling an attacker your PIN, and under certain circumstances you will, you can tell them a secondary PIN that hides your original wallet and shows a secondary one, nothing special is shown on the screen and ColdCard recommends having some coins, as much as your willing to use to protect your main wallet, to divert the attacker.

It also features a secondary chip to store the critical master secret, this Microchip does SHA-256 hashing and includes a true random number generator. It also employs resistance to Evil Maid attacks by checking the firmware and having a dedicated light turn green when the firmware is factory-signed and red when its not, the light status is controlled by dedicated circuity so rogue software cannot override it.

One of the key features is that ColdCard can be run entirely without connecting it to a computer, thus eliminating a whole vector of attacks, using a MicroSD chip you can create a new wallet from the device and import it to Electrum on your PC, you can also create transactions on Electrum, load them to the MicroSD card, sign the transactions in your ColdCard and transfer it back to Electrum to push it on the blockchain, all while using only a MicroSD card as your medium of transfer.

If you want to run it connected to a PC like other hardware wallets, there is also a micro usb port that you can use.

Comparing this to currently widely available hardware wallets, most of them rely on custom software and micro usb to relay transactions to the hardware wallet to confirm, and almost none of them have the Duress wallet feature, we’re glad to see the Bitcoin community working on more innovative ideas to secure the coins of regular users, in the digital age of money such innovations are as necessary as the lock on your door.


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