Quickstart! Start Here!

About the Bag

Your coldcard should have arrived sealed in a special bag: It has a large Coinkite logo, green text and a barcode with number underneath. This number is important and we call it the "bag number". Please make note of this number because the Coinkite factory has recorded this number into the secure area of flash memory of your Coldcard.

Before opening it yourself, please inspect the bag for damage or signs of being previously opened. After you open the red seal, it will show the word "VOID". If you find anything out of place, please contact support@coinkite.com with photos.

The purpose of the bag, and it's unique number, is to give you confidence that the Coldcard has come directly from the factory and has not been modified by anyone before you get started.

This is merely one of many layers of our security, and we know that plastic bags can be "hacked" with sharp knives and so on. This is an example of "Defense in Depth".

Example of bagged unit

Power Up

Connect a power supply to the Coldcard using the USB port at the top. Any Micro USB cable you already have can be used. You can connect the USB to a computer, but at this stage, a wall charger or USB power pack could also be used. We just need power, not data.

Terms of Sale

The first screen you will see looks like this:

terms screen

If you look closely at the right edge, there is a small scroll bar and arrow pointing downwards. Use the 5 and 8 keys to move up and down and see the full message.

The complete terms document can be found here. Press the OK key (checkmark, lower right) to accept the terms and continue.

Initial PIN

Before a Bitcoin seed is generated, you must select a primary PIN. This is your main defence against random people using your Coldcard when you are not around. Please pick good PIN codes!

On the Coldcard, the PIN consists of two parts, like these examples:

12-34
1234-5678
872323-39843
12-345678

The first part is called the prefix (1234-) and the second, the suffix (-4567). Each part must have between 2 and 6 digits. The prefix determines the anti-phishing words you will see each time you login.

When you pick your PIN code, you'll see the anti-phishing words associated with the PIN prefix. These words will be unique for each Coldcard. You may want to experiment with a few different PIN prefixes until you find some fun or memorable words. Regardless, you will need to remember those words, as it's important to verify those words before proceeding to the second part of the PIN—every time you login to the Coldcard.

As usual, you be asked to confirm the new PIN and enter it a second time.

Important

No-one can help you if you forget your PIN. There is no back door, hints or alternative ways into the Coldcard.

Use Longer PIN

We strongly recommend using "four plus four" digits in your PIN: 1234-5678
Having just "two plus two" is permitted, but might allow brute force attacks.

New Wallet or Import

Once your PIN has been established, it's time to setup your wallet. You should see a menu like this:

new wallet

If you already have a BIP39 seed, or a backup from another Coldcard, or even a XPRV (extended private key), you should choose Import Existing menu item. However, most new users will start with New Wallet.

New Seed (New Wallet)

Choose New Wallet to generate 24 words using the BIP39 word list.

The words are shown to you, and if you don't like them, you can press X to start over. Write down the seed words, in order, on the provided card or some other paper. Please be careful at this stage and be 100% sure that each word is recorded correctly. You might want to duplicate them by hand at this point too (ie. make backup copy).

Once you've written them all down, press OK to continue to the quiz. The Coldcard will ask you what each word is, in random order. We do this to verify your backup is correct. If at any point, you are unsure of a word, you may see them again by pressing OK.

If you press X to cancel, these words will be forgotten and the entire process would need need to start over!

If you complete the quiz successfully, your new Coldcard is ready to be used.

Important Warning

It is critical to write down the wallet seed. Do not use this product without the seed written down and stored safely offline. Do not save the wallet seed onto a computer or mobile phone. Do not take a picture of the seed words with anything other than a chemical camera.

Import Wallet

From this menu, you can import seed words generated on another system. Choose the number of words: 24, 18 or 12 words and the following menus will allow you to drill down to appropriate BIP39 word (English only).

Alternatively, you can import a backup file from another Coldcard. You will need the backup file (7z) on the MicroSD card, and you must enter a 12-word password that was provided at the time the backup was created.

To import an XPRV, you must provide a cleartext file on MicroSD with a BIP32 base58-serialized extended master private key. It should start with xprv and be on a single line of a text file. We don't care what else is in the file. Please note there is no encryption for this method, and therefore, it is somewhat hazardous and only recommended for testing purposes.

Ready to Sign!

Once your PIN code and master seed have been established, your Coldcard is ready for daily operation. You should see a menu like this one:

ready to sign

If the USB port is connected to a computer, the Coldcard makes itself available to that computer. (The Coldcard is invisible to the attached computer, if any, until the PIN code is correctly entered.) You can use a desktop wallet, such as Electrum, to pair with the Coldcard and then send it transactions to be signed.

Alternatively, you can use a MicroSD card to bring in transactions and sign them.

Using with Electrum via USB

Using Coldcard Offline

Steps:

skeleton wallet warning

When you want to spend from this wallet:

What's Next

Keep your Coldcard in a safe location. Everytime you remove it from storage and use it, please consider the following: