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COLDCARD Mk5 is the compact expression of COLDCARD's feature depth. It pairs dual secure elements, a Gorilla Glass screen, an improved keypad, and a clear case with MicroSD, NFC, USB-C, and Virtual Disk workflows. No COLDCARD account or required companion app: choose compatible wallet software and keep room for passphrases, seed tools, Trick PINs, and multisig policy when needed.

REQUIRED BEFORE WALLET SETUP

Update before using your COLDCARD.

Firmware updates require a PIN. Inspect the tamper-evident bag, set your PIN, then stop at the main menu before choosing a seed or restore option. Install and verify the current recommended standard firmware. Do not generate or import a seed, restore a backup, or fund the wallet until the update is complete. Current standard firmware then requires 65 key presses, 50 physical dice rolls, or 128 physical coin flips for each new seed. If an existing seed was created on affected firmware, follow the migration guide rather than only updating the device.

100% Backwards Compatible

Protect your existing investment. Migrate seamlessly from existing COLDCARD devices.

Improved Keyboard

A refined keypad designed for precision entry.

Bigger, Brighter Screen

Protected by Gorilla Glass for maximum durability.

Relocated USB-C Port

Conveniently positioned for easier access.

Improved NFC

Faster, more reliable wireless communication.

PushTX

Any NFC-enabled phone with internet access. No companion app or setup. Just tap to broadcast.

Available in Multiple Colours

Choose the one that matches your style.

Compact Design

Small enough to hide anywhere. Big enough to secure everything.

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Dual Secure Element for Key Storage

COLDCARD uses two Secure Elements, from different vendors, to protect your Bitcoin. Specifically, the COLDCARD uses Microchip's ATECC608 and Maxim's DS28C36B to store the critical master secret: the 24-word seed phrase for your BIP-39 wallet.

Genuine vs. Caution Lights

To resist Evil Maids, we sign our firmware with a factory key. During boot-up, the firmware's signature will be verified and the appropriate Green/Red light set. The circuit for the lights is exposed on the top surface, so physical tampering will be visible.

Anti-phishing Words

The PIN code on COLDCARD is divided into two parts. You first enter the prefix and then you will be shown two words on-screen. Those words are unique to each PIN prefix and COLDCARD.

Physical Security

The carefully designed PCB increases the SE probing difficulty. Our clear case is part of our security model too, so you can look and see if a "hardware implant" has been inserted inside your device.

Bring Your Own Entropy

Every new seed combines fresh device entropy with one required method: 65 key presses with unpredictable timing, 50 physical dice rolls, or 128 physical coin flips.

Mk4/Mk5 5.6.2 adds View TRNG Words and offline verification of dice-roll or coin-flip mixing with verify_seed_mix.py. The tool does not support key mashing. Follow the seed-generation instructions.

Trick PIN Features

COLDCARD has even more tricks up its sleeve!

xkcd comic about security
xkcd #538

Duress PIN

You may define an optional "duress PIN code". If anyone enters that PIN code, nothing special is shown on the screen and everything operates as normal... However, the bitcoin key generated is not the main key. It is effectively a completely separate wallet!

Countdown to Brick PIN

This is a covert variation of the BRICK ME PIN mode. It forces a time delay when logging into the Coldcard. Once set, this special mode covertly bricks the Coldcard (or optionally merely wipes the seed).

BIP-39 Passphrases (25th word)

For any wallet intended to hold an amount whose loss would be materially harmful to you, use a strong, unique BIP-39 passphrase. Back it up separately, record the passphrase wallet fingerprint, and test recovery before depositing funds.

Brick Me PIN

Another PIN can also be defined, which we call the "Brick Me" PIN. Using that PIN code at any PIN prompt will destroy the dual secure element and render your Coldcard worthless.

Login Countdown

Force a time delay when logging into the Coldcard. Once enabled, you must enter the PIN correctly, wait out a forced delay, then enter your PIN correctly a second time to get in.

xkcd comic about security
xkcd #538

More than a transaction signer

Mk5 can manage multiple seeds, configure Trick PIN responses, and enforce limits, timing, destinations, and optional 2FA through COLDCARD Co-Signing.

Temporary Seed and Seed Vault

Temporary seed is a temporary secret completely separate from the master seed, typically held in RAM and not persisted between reboots in the Secure Element.

Seed Vault adds the ability to store multiple temporary secrets in encrypted settings for simple recall and later use. Stored secrets are AES-256-CTR encrypted with your master seed's key.

COLDCARD Co-Signing

COLDCARD Co-Signing (CCC) is a powerful feature that lets you create automated multisig wallets, protected by user-defined spending policies for enhanced security and control.

When enabled, CCC adds a second seed (the Spending Policy Key) to your COLDCARD, which works with your main seed and additional backup keys to create 2-of-N multisig wallets.