This article demonstrates using a stainless steel backup for securing bitcoin against fire & flood. This backup will work for securing any BIP39 word-phrase and it is specially tailored for Samourai Wallet. This article is also available on the Bitcoin Magazine website here.
Taking self custody of your bitcoin is serious business, it is radical responsibility. You and you alone are responsible for the security of your bitcoin. The majority of wallets used for securing bitcoin will provide the user with a 12 or 24 word seed phrase. This goes for mobile wallets, desktop wallets, and hardware wallets. But storing the wallet information in a digital media such as a text document or image file is risky because anyone with access to that digital file will be able to withdraw the bitcoin from that wallet. Writing down these words in order on a piece of paper is a great way to ensure that the information necessary to restore the wallet is secure in a way that is never accessible by internet connection. But how secure is paper really? What happens if there is a fire where this paper is located? What about a flood? Preventing loss of bitcoin by securing the seed words in a steel media is a great way to protect against fire and flood.
A passphrase can also be used to add additional wallet security. Passphrases are kind of like having a 13th or 25th word, but only you know what the passphrase is. The passphrase can be any combination of letters, numbers, or special characters. No one can help you recover your passphrase, so be sure to take care and secure it accordingly. If you lose your passphrase and need to recovery your wallet, the 12-words alone will not be enough. The RoninSteel backup, designed by the RoninDojo team, is tailored for Samourai Wallet users however, it will work with any BIP39 seed phrase. Upon receiving the RoninSteel backup, you will find:
Envelope with tamper evident seals
Stainless steel plate measuring 6-1/4" x 3-1/4" x 5/64"
12-word seed phrase template sticker for Samourai Wallet
Passphrase template sticker
If using Samourai Wallet then the 12-word seed phrase will be punched on one side of the plate and the passphrase will be punched on the other side of the plate.
Alternatively, there are other sticker templates available for 24-word seed phrases. The idea with these is that you would use both sides of the steel plate for the words and a second plate for the passphrase, if applicable. You will notice that there are places to indicate the word number and whether or not a passphrase is used.
I'll demonstrate how to generate a new seed phrase and passphrase using Samourai Wallet and then how to secure them.
The basic steps to create a new wallet are:
Step through the introduction
Allow file access
Connect a Dojo if you have one
Create a passphrase
Create a PIN
Generate 12-word phrase
Once the wallet is setup, the 12-word seed phrase and passphrase can be transferred to the steel backup. First, gather the steel plate, the 12-word seed phrase sticker, a sharpie, a spring loaded punch, and also the 12-words by navigating to the 3-dot menu in the upper right-hand corner of the Samourai Wallet application >Settings > Wallet > Show mnemonic.
Carefully place the the sticker on the steel plate so that all the edges are aligned. Then use the sharpie to mark the corresponding circles on the sticker. The A-Z alphabet runs horizontally and the 12-word columns run vertically. You only need the first 4-letters of each word as all words on the BIP39 list have a unique sequence of the first 4-letters. Double check your work before using the spring loaded punch. Make sure to also indicate if you are using a passphrase in the lower right-hand corner. Then peel the sticker off.
Once the sticker is removed, the information is obfuscated and just looks like some random dots. If someone were to gain access to this steel plate, they would not be able to determine the information contained here without a recovery sticker.
Next, you can stamp your passphrase on the reverse side of the plate. Double check that your passphrase is correct by navigating to the 3-dot menu in the upper right-hand corner of the Samourai Wallet application >Settings > Troubleshoot > Passphrase/backup test. Then carefully place the passphrase sticker on the steel plate so that all the edges are aligned. Again, use the sharpie first and then double check you work before using the spring loaded punch. You will notice that there are rows on the top and bottom edges indicating which column the character for a particular row belongs.
Then peel the sticker off and the information is obfuscated.
Now all the necessary information to restore your wallet is secured in a durable stainless steel media and it is obfuscated. You can use the included red envelope and seal it with the included tamper evident sticker. Then store this securely as if it were gold or jewelry.
Let's see how well this stainless steel plate withstands white-hot temperatures near melting point, 1,500°C:
The plate survived the fire test, but let's see if the information is recoverable...
The information was 100% recoverable! Even after the fire test, by applying a recover sticker the 12-word seed phrase and the passphrase were both recovered. The recovery stickers are clear in the little circles so it is easier to see the divots. Using the tip of the spring loaded punch, I was able to locate the divots and impress the sticker to make it more visible.
Wallet Recovery Check:
In conclusion, the RoninSteel backup plate is durable enough to withstand white-hot temperatures and still secure your wallet recovery information. The plate is small enough to easily conceal anywhere in your home. One plate can be used for a Samourai Wallet 12-word phrase and passphrase or multiple plates can be purchased for 24-word seed phrase/passphrase combinations. The tamper evident seal on the envelope adds some peace of mind in knowing if anyone has accessed the steel plate. By removing the stickers, the information is obfuscated in a way that makes it useless to anyone who doesn't know exactly what it is and has the stickers to use. All in all I thought this was a cool way to secure the wallet recovery information. To learn more about Ronin Dojo check out these resources:
If you enjoyed this content, leave me a tip here: Donate.
This article is also available in a Twitter thread here.