Coldcard Review (2021)

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Coldcard Review
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Summary

The Coldcard is an “ultra-secure” bitcoin-only hardware wallet that is packed full of security functionality that helps you to keep your funds safe.

This includes a number of duress features, countermeasures to prevent evil maid and supply chain attacks, as well as the ability to use the Coldcard without ever connecting it to another device.

The Coldcard isn’t right for everyone, but it’s easily my favourite hardware wallet.

Coinkite’s Coldcard is a popular Bitcoin (BTC) hardware wallet that’s been available since 2018. The latest revision, the MK3, was released in October 2019.

Without a doubt, it’s my favourite hardware wallet.

In this Coldcard review, I’m going to walk through everything you need to know about it.

Advantages & Disadvantages

Advantages

  • Open-source software.
  • Built with a dedicated secure element.
  • Simple, compact, and lightweight design.
  • Can be operated without ever being connected to a computer.
  • BIP39 passphrase support.
  • Includes plausible deniability features, login countdown settings, and can be configured to self-destruct.
  • Compatible with a few popular bitcoin wallets (e.g., Electrum and Wasabi).
  • Wallet (and settings) can be backed up to a microSD card.

Disadvantages

  • Only supports Bitcoin (BTC).
  • Quite expensive ($120 / €100 / £88).
  • Isn’t as beginner-friendly as alternative hardware wallets.

What Is a Coldcard?

The Coldcard MK3 is the third iteration of this popular hardware wallet (by Coinkite).

Making a transaction using a hardware wallet like this requires physical access to the device. That’s because the critical information (the private key) is securely kept on the device itself.

Hardware wallets are widely recommended across the crypto-community. They’re not free, but they’ve made it simpler and easier for more people to securely store their cryptocurrencies.

What other things do Coinkite produce?

Coinkite is the same team that’s behind the:

  • OpenDime: Small, barebone USB sticks which enables you to spend bitcoin like cash (i.e., without an on-chain transaction). Check out my OpenDime review for more details.
  • SEEDPLATE: Tough, two-sided piece of steel which can be used to backup your bitcoin wallet seed. This performed well in Jameson Lopp’s stress tests.
  • BLOCKCLOCK: Device that can be configured to display the current bitcoin price and other types of data.

Coldcard MK3 Price

You can currently buy the Coldcard MK3 from the official Coinkite website for $119.97. That’s roughly £85 or €100.

The Coldcard MK3 ships from Canada, but the shipping costs to the UK aren’t too bad. When I ordered mine, I was asked to pay $9.00 for basic delivery (which is about £ or €) to the UK.

Fortunately, I wasn’t charged any import duties when this arrived in the UK and it only took about 10 days to arrive.

You can pay with a debit/credit card or Bitcoin (BTC).

What’s in the Bag?

Here’s what’s in the bag:

  • The Coldcard MK3 hardware wallet.
  • Backup card (where you can write down your 24-word seed).
  • Coldcard sticker.

A micro-USB cable isn’t included. You can buy cheap ones from Amazon (like this) if you don’t have one you can use.

You’ll also need to buy a compatible microSD card if you want to use the Coldcard without ever connecting it to a computer.

What microSD cards are compatible with the Coldcard MK3?

Coinkite doesn’t provide a list of compatible microSD cards. However, they recommend that you choose a microSD card that is FAT formatted (FAT32 or FAT12) and smaller than 32GB.

This SanDisk Ultra 32GB microSD Card worked for me.

You can also order this Industrial Grade microSD Card from the official Coinkite store.

Design

It’s a bit bulkier than alternatives out there, but the Coldcard still comfortably sits in the palm of your hand (88 x 51 x 9mm) and is lightweight (approx. 30g).

It has a screen that’s clear and easy to read (128 x 64px OLED), as well as a responsive, adult-sized numeric keypad.

The Coldcard’s clear plastic case is a purposeful design feature. This allows you to visually check that your device hasn’t been tampered with.

Supported Cryptocurrencies

Bitcoin (BTC) is the only cryptocurrency that you’re able to store using the Coldcard MK3. I don’t expect this to change either, as it’s explicitly marketed as a Bitcoin (BTC) only wallet.

Screenshot from the Coldcard website.

If you want to secure your alternative cryptocurrencies, then you’ll want to consider getting a hardware wallet like the Ledger Nano S or Trezor One. Both these alternatives support more than 1000 cryptocurrencies and tokens.

Supported Wallet Software

Coinkite hasn’t built any custom software that can be used to interact with the Coldcard.

However, the Coldcard is compatible with Bitcoin Core and a handful of popular Bitcoin (BTC) wallets. This currently includes:

The Coldcard also works with BTCPay Server, Casa, and Unchained Capital.

Security Features

The Coldcard MK3 has a truly impressive number of security features.

Here are the main things:

  • Stores your seed words inside of a dedicated secure element (ATECC608A). For more detailed information, check out this.
  • Firmware is open-source – which means that it can be audited for problems by anyone.
  • Firmware’s signature and device’s flash memory are verified on each boot-up. If they don’t match, then the caution light will be switched on. Find out more here.
  • Supports Multisig Bitcoin (BTC) wallets (with up to 15 co-signers).
  • You’ll be shown two anti-phishing words whenever you boot-up the device and insert the first half of your PIN code. This verifies that the Coldcard you’re using is really yours.
  • Coinkite have taken steps to help you verify that a Coldcard ordered from them hasn’t been tampered with. For instance, it’ll arrive in a “tamper-evident” bag with a serial number that should match the code embedded in the secure element. See here for more details.

Air-Gapped Operation

One thing about the Coldcard which stands out is that it can be used without ever connecting it to your computer. You can do everything offline – including going through the initial setup of the device, as well as receiving and sending Bitcoin (BTC).

You can do this by ensuring that you only ever connect your Coldcard to a battery pack or power outlet. As the Coldcard has a microSD slot, you can then transfer data in and out using a microSD card.

This is awesome, but it will make it more of a pain to send Bitcoin (BTC).

if you’re curious what the process of doing all this looks like, check out this visual guide or this 2-minute video.

Duress Features

The Coldcard MK3 includes more plausible deniability functionality than any other alternative hardware wallet that I’ve checked out.

If someone was physically forcing you to open up your device (i.e., $5 wrench attack), then these functions could be used to redirect the attacker to a decoy wallet, delay them from accessing your main wallet, or completely destroy the device.

  • Duress PIN: Setup an additional PIN code that redirects you to a completely separate wallet.
  • BIP39 Passphrases: Select a 25th word (i.e., passphrase) which encrypts your seed words and generates a separate wallet. You can use this function to multiple separate wallets. Find out more here.
  • Login Countdown: You can force a specific time delay (up to 28 days) before the Coldcard can be used after entering your PIN code.
  • Brickme PIN: Configure an additional PIN code that triggers the destruction of the secure element when entered (rendering the device unusable). You can also enable a specific delay (up to 28 days) before it’s obvious that you’ve entered the Brickme PIN.

It’s important you fully understand these functions before you enable them on your Coldcard. For more information, check out this documentation or this video.

Coldcard Alternatives

There are plenty of alternative cryptocurrency hardware wallets out there.

Here are three of my favourites:

BitBox02

Launched in September 2019, the BitBox02 is an improved version of the original BitBox hardware wallet (i.e., BitBox01).

It’s a swiss-made hardware wallet that uses the same secure element as the Coldcard MK3 and is also open-source.

Like the Ledger Nano S and Trezor, it allows you to store loads of cryptocurrencies. But if you only care about storing Bitcoin (BTC), then there’s a Bitcoin-only edition with “radically focused firmware”.

Learn more about the BitBox02 here.

Trezor One

Trezor One Doge Homescreen

 The Trezor One is another popular hardware wallet that’s been on the market since 2014, which makes it the world’s first Bitcoin (BTC) hardware wallet.

It supports tons of cryptocurrencies and tokens and has a fantastic, easy-to-use wallet interface. Most of Trezor’s hardware and software is open-source, which means that anyone can check it out.

You can buy the Trezor One for roughly £50 from the official Trezor website.

Check out my Trezor One review to learn more about it.

Ledger Nano S

Front of the Ledger Nano S

The Ledger Nano S has sold more than 1.5 million units since it launched in 2016 – making it one of the most popular hardware wallets around.

But FYI: Ledger suffered a data breach in 2020 which exposed personal details (including names, email addresses, home addresses, and phone numbers) about thousands of its customers. This, understandably, hasn’t gone down well with the crypto-community and has led to an increased number of phishing attempts.

You can currently get it for £54.50 from the official Ledger website. This makes it one of the most affordable ways to store Bitcoin (BTC) and hundreds of other cryptocurrencies and tokens. 

Check out my Ledger Nano S review to learn more about it.

Summary: Best Bitcoin Hardware Wallet

There’s nothing quite like the Coldcard MK3 on the market.

Here’s what stood out to me:

  • It uses a specialised chip to secure your seed words, but all of the firmware code is open source.
  • You can use the Coldcard without ever connecting it to an internet-enabled computer. This is awesome.
  • It’s packed full of security features. This includes duress functionality that other wallets I’ve reviewed don’t have (e.g., login countdowns), as well as firmware and device verification every time the Coldcard is booted up.

It’s a unique beast and, without a doubt, my favourite hardware wallet.

But it’s not for everyone. It’s an unapologetically bitcoin-only hardware wallet and nowhere near as beginner-friendly or cheap as popular hardware wallet alternatives like the Ledger Nano S and Trezor One (which put a huge emphasis on usability).

But if your main concern is keeping your Bitcoin (BTC) funds super-secure, then the Coldcard might be worth a closer look.

Find Out More

Have a Question?

Thanks for checking out this Coldcard review!

Have a question you want to ask about Coinkite’s Coldcard?

Let me know in the comments section below.

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