Coldcard Q is like a Swiss bank — only in your pocket. Built by true cypherpunks.

The device has open-source code that’s available for review and study (on GitHub).

Air-Gap operation

COLDCARD works fully autonomously and does not require a connection to a computer. The device can be powered using a regular power bank or a power adapter, which provides security and convenience throughout its entire service life.

With COLDCARD you can:

• Set up and choose an initial PIN code.
• Generate your own 24-word seed phrase using the built-in random number generator.
• Import existing private keys.

Anti-phishing words

The COLDCARD PIN code consists of two parts, for example, 1234-5678. After entering the first part (1234), two unique words appear on the screen — words that only your original device can display.

Memorize these words and check them before entering the second part of the PIN (5678). This protects you from fake devices, which won’t be able to show your unique words.

Security indicators

COLDCARD is protected against attacks involving physical access. The device firmware is signed with a factory key, and at startup it verifies the signature and checks almost every byte of flash memory. After verification, a green or red indicator lights up.

The indicator is directly connected to the Secure Element, which prevents it from being faked using malware. In addition, the indicator control circuitry is located on the visible part of the device, so any interference is immediately noticeable.

Dual protection

COLDCARD uses two Secure Element security chips from different manufacturers to reliably protect your recovery phrase.

To compromise the device, an attacker would need to break both Secure Elements and the microprocessor at the same time — which is practically impossible.

Seed phrase generation

If you don’t want to use the wallet’s built-in random number generator, you can generate the recovery phrase yourself. The wallet includes a feature that lets you create a BIP39 seed phrase using dice rolls. Simply write down the results from 1 to 6 for each roll (it’s recommended to do 99 rolls). In the end, you’ll get a seed phrase where each word is based on a random number.