Crypto Security How-tos

How to back up your seed phrase on Cryptosteel.

A highly secure way to backup your seed phrase is by recording it onto indestructible metal plates. This type of backup strategy is one of the most likely to pass the "test of time."


Backing up your seed phrase to steel plates offers a robust solution that is subject to only a few threats.

Don't give a steel plate vendor your seed phrase to stamp or engrave for you! This is a "DIY" task.

Once created, protect it well from discovery and theft.

Some options are Cryptosteel, Ledger CryptoSteel Capsule, Crypto Key Stack and Hodlinox (engraveable options), ColdTi (titanium), and Billfodl.

​When it comes to a decision about how to back up your seed phrase, you have to consider your personal circumstances, and weigh the pros and cons of the many options that exist.

For offline, long-term, cold storage backups, utilizing steel is one of the most secure options. Steel requires no software, is nearly indestructible, and the backup process is completely manual and offline. Furthermore, the steel devices that are on the market today don't look like a seed phrase backup to those not already familiar with crypto seed phrases - this offers a degree of "security through obscurity" that could deter a common thief. (However, you should not rely on that protection! Always keep your backup in a safe or lockbox.)

Steel backups exist in a variety of formats. If you are handy with metalworking, you could even create a steel backup yourself. This review showcases Cryptosteel, which is produced from the original blueprints of the open-source Cryptosteel steel backup solution that was the first metal backup solution on the market. Cryptosteel sells its original model as the Cassette and has since added a Capsule version. Since the blueprint is open-source, the "cassette-type" steel wallet backup solution may be available from a variety of providers. If you consider several different steel backup solutions, consider the quality of each before making a purchase, since the place of manufacture, the grade of steel, and other characteristics may vary.

How is the seed phrase recorded onto the card?

A few companies offer ready-made steel plates, and all you have to do is input your seed phrase onto the steel. Different companies offer different ways of doing this, from sliding metal tiles into locking slots, to engraving, or using a metal punch. If you are handy and have the tools, you can even make a steel plate backup yourself.

There are 2 rules that you must follow if you are considering using metal plates as a backup:

1. Simplicity is the win-win! Some solutions are way too complicated. Fewer pieces = less chance for failure.

2. You should never ever provide the card manufacturer with your private key or seed phrase for "engraving" or whatever process they use. Unfortunately, some reckless manufacturers expose their customers to this severe risk ... pease keep your seed phrase safe by avoiding them.

What risks are steel cards still subject to?

Backing up to a steel plate is great - but don't forget about the importance of keeping that plate in a safe location. There is no "data security" layer present on a steel plate, so it becomes critical to implement steps to prevent unauthorized people from accessing the seed phrase or steel plate.

  1. Consider encrypting your seed phrase before committing it to steel - that way if the plate is exposed, you still have a layer of protection.
  2. Keep it in a safe place! If the plate is exposed, then your seed phrase is exposed, and you become at risk of your funds being drained.

Why protect Your Seed Phrase?

In the world of cryptocurrency, you are your own bank, and with great power comes great responsibility. Public blockchain cryptocurrencies are run on open, permissionless systems, where transactions are irreversible. There is no credit card company or bank to call and dispute the charges.

Your seed phrase provides full access to your wallet, and because of this, protecting your seed phrase is critically important. You can think of your seed phrase as equivalent in legacy finance to someone having all of your online banking information. Anyone with your seed phrase can access your wallet, just as anyone with your online banking information can log in to your banking account.

Protecting/backing up your seed phrase serves two purposes:

Backing up your Wallet: Allows you to reconstruct your wallets in cases of device failure, moving to a new device, etc.

Securing your Wallet: Prevents bad actors from gaining access to your seed phrase, which would allow them to steal funds.

What is the Cryptosteel

Cryptosteel was the first steel seed phrase backup solution on the market. The concept was developed in 2013, and the blueprints were later released as open-source software. The rectangle block resembles a cassette deck, as suggested by its model name "The Cassette." The frame is a little bigger than a credit card and will fit easily into your pocket (although the pocket is a poor choice of locations for safekeeping).

The purpose of steel backup solutions like Cryptosteel is to safeguard your seed phrase from extreme scenarios. The Cryptosteel Capsule will survive fire up to 1400C/2500F degrees, and the Cryptosteel Cassette up to 1200C/2100F. (For reference, a house fire is around 600C/1100F degrees.) It will survive physical damage from flooding, electric shock, corrosion, magnetic shockwaves, and extreme pressure.

The form of the device does not appear to the untrained eye as a seed phrase backup solution - it appears simply as a block of metal. However, someone who is familiar with the devices will recognize what it is. After you have backed up your seed phrase, choose a proper location for storage, such as a safe or a lockbox.

The device is made from 100% AISI 304 grade stainless steel - the Capsule form also incorporates AISI 303 grade steel - and the company says that it can go undetected by many scanners and metal detectors. Since tech is always advancing, this is not a safe long-term reliance if your objective is stealth and your threat profile involves entities searching your house with metal detectors. If this is the case, embed the device onto a stainless steel object, preferably inside a wall, and your Cryptosteel will become masked and invisible to metal detectors.

How to use the Cryptosteel

When you first open the Cryptosteel, you will notice that the instructions are printed on the inside top of the cardboard box, along with pictures for each step. The device and the engraved steel tiles are neatly embedded into cushions.

0. Cryptosteel Unboxing

Cryptosteel unboxing

Remove the Cryptosteel device from the box, and the plastic container holding the engraved steel tiles. Printed on the box, underneath the plastic container, is an outline that maps out where each letter can be found in the plastic container. Each box shows 2 letters because the engraved steel tiles have one letter on each side.

Do you notice the elongated box in the middle, with numbers and symbols? BIP39 seed phrases do not contain numbers and symbols, but BIP39 does support adding a passphrase to the end of your seed phrase: this is sometimes referred to as the 13th or 25th word. However, the steel wallet only has 24-word options to fill, so if you have a 25th word, it won't fit. If you have a 12-word seed phrase, it will fit.

Cryptosteel Outline and steel tiles

Cryptosteel device

1. Setup Cryptosteel

​Now that you are familiar with the device and have had a chance to look everything over, let's back up your seed phrase.

Step #1 - "Open the case by sliding upper and lower containers like a fan."

When you first hold your Cryptosteel, the device frame is closed and locked, and it appears as a rectangular block of steel. To back up your seed phrase, first, you need to open the device.

To open the device easily, place your fingers near the top of the device, and slide each side in opposite directions.

Identify the top of the Cryptosteel by looking for the side that has a thin rectangular opening, which separates the two blocks of metal. In contrast, the bottom of the device will be completely closed and solid.

You shouldn't have to push too hard to open the Cryptosteel. If you are pushing hard, you are likely pushing near the bottom of the device.

Opening Cryptosteel

2. Unlock the frame by turning the screw counter-clockwise

Now that the Cryptosteel is opened, notice that the device frame is actually 2 plates of steel, with each steel plate holding 12 words, so that you can store your seed phrase.

The way that you store your seed phrase is by sliding engraved steel tiles into the Cryptosteel and then locking it. By default, the device comes locked. To unlock it, you will need to use a flathead screwdriver, or something similar, to turn a screw counter-clockwise. In our testing, we were also able to use a credit card and a fingernail to turn the screw.

It is easy to identify the screw, because it is the only screw on the device that has an opening to be turned. If you lay the Cryptosteel horizontal, the screw is on the top right.

Unlocking the Cryptosteel

3. Release the safety lever by pressing inside the long slot with a small tool.

Before you can open the frame, you need to release the safety lever. The safety lever prevents you from accidentally opening the frame and having your steel tiles fall out.

To identify the safety lever, look for the thin rectangular opening with a small half-oval inside of it. On the 1-12 word side, it is underneath word 12. On the 13-24 word side, it is underneath word 24.

To release the safety lever, you need to push out the metal piece inside the long slot. It's possible to push it out using your finger, but it's much easier to use something like a screwdriver or similar object.

4. Open the frame while safety lever is released

Once the safety lever is released, you can easily open the frame by sliding it open. When the frame is shut, it protects the steel tiles from falling out by keeping them locked in place. After you have opened the frame, you are ready to start placing your seed phrase in the Cryptosteel.

Opening the frame on the Cryptosteel

5. Insert the slots with the first 4 letters of each word

With the frame open, you will be able to slide the engraved steel tiles into the Cryptosteel. Notice the numbers engraved on the device. It is extremely important to follow the correct order! The Cryptosteel has 3 rows, each with 4 words.

Due to the way BIP39 works, you will only need the first 4 letters of each word. This is because each word of the 2,048 word list has unique first 4 letters. If you have a word that only has 3 letters, feel free to use a steel tile from the numbers and symbols box to represent the "extra" space.

Now, it is time to open the plastic case containing your letters, and put them into the Cryptosteel:

- Identify word 1 of your seed phrase, and identify the position of word 1 on the Cryptosteel.

- Gather the engraved steel tiles of the first 4 letters of your word.

- Insert the 1st letter first, position it in the slot, and slide it to the bottom.

- Insert the remaining engraved steel tiles to complete your 4 letters.

- Repeat the process for the rest of your 12 words.

*If you have a seed phrase that has more than 12 words, keep following this guide till the end, and then repeat the same steps for the second steel block that contains words 13-24.*

Sliding the engraved steel tile into the Cryptosteel

First 4 letters of the first word in the Cryptosteel

When you are finished sliding in the steel tiles, this is what it will look like

6. "Close the frame and bend the safety lever back inside the slot

Now that all the slots are filled, the next step is to close the frame and close the safety lever. When doing this step, be very careful to keep the Cryptosteel flat and horizontal. If you tilt it too much, it is possible for the steel tiles to slide out!

Before you can close the safety lever, you have to close the frame. Closing the frame is super-simple: just push it back down into place, and it should naturally fall into place without much resistance.

To close the safety lever, you need to push it back inside the slot. This requires a little more resistance than closing the frame. If the safety lever doesn't want to bend back into the slot, just give it a good push.

7. Lock back the frame by turning the screw clockwise

Recall Step 2, when you had to unlock the frame by turning the screw counter-clockwise? This step is the opposite of that: you are going to lock the frame by turning the screw clockwise.

This is what your Cryptosteel will look like once you have locked the frame

8. If you have a seed phrase more than 12 words, repeat these steps for the other side

​The Cryptosteel is made up of 2 steel plates, with each steel plate containing 12 words. You have just completed setting up the Cryptosteel for a 12-word backup ... congratulations!

But what if you have an 18, or 24-word seed phrase? If so, repeat these same steps for the 2nd steel plate to back up the remaining words of your seed phrase.

When you are done, slide the 2 steel plates together so they form 1 steel plate. When finished, it will look like this:

The advantages of using Cryptosteel

Using this method to backup your seed phrase provides protection from destruction via disaster. In today's world, you do not need to look far to see natural disasters happening around the world. From Texas freezing over, to fires in California, Cryptosteel ensures that your seed phrase is protected, and comes out completely intact on the other side.

The ideal solution

​Cryptosteel is near-perfect as a long-term backup and storage solution. Since the steel wallet is a physical device, storing it in a safe place that is under your control is crucial. The best place to store the Cryptosteel would be in a safe, lockbox, or cleverly hidden - for example, embedded in a steel object.

The Cryptosteel is not without downsides. For starters, recovering your seed phrase requires physically retrieving the device, which could be tricky, depending on your chosen hiding place.

Today, next-generation digital backup solutions are available that utilize military-grade encryption, providing the same level of security as the Cryptosteel, and incorporating high levels of fault-tolerance and ease of access to your backups. You could choose to have the best of all worlds by using the Cryptosteel to provide protection against disaster and destruction, combined with next-generation tools like Vault 12 for your day-to-day use - with the same level of security.

Crypto Security How-tos

How to back up your seed phrase on Cryptosteel.

A highly secure way to backup your seed phrase is by recording it onto indestructible metal plates. This type of backup strategy is one of the most likely to pass the "test of time."