Securing Your Seed Phrase with Washers

[fillippone]

I added a few suggestion that came out from the comments in the OP.
I also corrected some embarrassing typos (I love "tinkering", not "thinking"!)

Hopefully, more valuable content will continue to come!

No, I didn't added the Etna suggestion, yet.

@fillippone this is truly one amazing megapost and you even provided videos for lazy people (cool music but I expected something more Italian).
Can you please tell me about material that is used for making Hermetic container?
I have seen few of these before on aliexpress and ebay but I think most of them were cheap and made from aluminum if I remember correctly.
It would add to structural integrity a lot if this could also be made from stainless steel.

Also your Italian videos are coming later.

The container is in a very light aluminium.
Not more structural stiffness is needed, as per Jameson Lopp test.
Also, in case of levate temperature, aluminium could be easily removed, without transforming the washers + case in an unmanageable blob of metal.

[Welsh]

I know the cost section might put a lot of users off the idea of doing this, but ignore the total cost, because the total cost is likely not going to to be anywhere near that. Since, most of these items, people already have especially if they're a home owner. For example, I have millions of washers/screws (including the size required), I have a sledge, gloves, duct tape, hot glue gun, and a micro fibre cloth. That has already reduced the price by 35+ euros based on the OP's pricing. Although, I bet I have a tonne of other stuff in storage that can either be substituted to a degree or already have. For example, the stickers could potentially be substituted.

Hide it in something dirty like coffee grounds or diapers.

This is just going to draw more attention to yourself, since whoever is snooping in your bins, will now be asking why your feeding washers to your baby. Nah, but in all seriousness that's a good idea, even some of the lowly of thief's aren't going through diapers.

Interesting way of storing the seed. I suppose stamping is better at remaining legible than say, etching it. If anyone got a hold of this, they'd still be able to use it right? Is there any additional thing that can be done to prevent that or at least make it harder for them to access?

What do you think of like doing a simple encoding of the passphrase so that it'll take longer for them to access the content?

You could encode it if you really wanted too, but depending on your threat model could potentially be overkill. However, to answer your question if someone got their hands on the washers it contains the seed, so they would be able to use it just like anyone else. This basically protects against losing the seeds though various natural threats, for example fires, flooding to degradation of materials. Steel washers are decent at surviving most things, maybe not very high temperatures, but it really does depend on how you store them, hence the container suggested.

Although, if you've got into this much effort, it's probably safe to assume you also have at least some physical security in place to prevent prying eyes. The security labels are a good idea, but effectively if the container has been opened, and therefore the stickers have been torn, you can safely assume that its already been compromised. It's more of a warning that it has been compromised, that something that'll help you save it, if you get what I mean. It doesn't necessarily safeguard your seed.

[n0nce]

I know the cost section might put a lot of users off the idea of doing this, but ignore the total cost, because the total cost is likely not going to to be anywhere near that. Since, most of these items, people already have especially if they're a home owner. For example, I have millions of washers/screws (including the size required), I have a sledge, gloves, duct tape, hot glue gun, and a micro fibre cloth. That has already reduced the price by 35+ euros based on the OP's pricing. Although, I bet I have a tonne of other stuff in storage that can either be substituted to a degree or already have. For example, the stickers could potentially be substituted.

Honestly, the raw material cost is nothing. 4€ for washers and a few euros for the stamp (you can skip that if in a pinch). Tools should be easily available in any household or can be borrowed by some friend without any weird questions.
All the other stuff like tube, stickers, hot glue etc. aren't needed, so while fillippone went total overkill, I think washers are actually the absolute cheapest way to get a steel wallet backup.

The letter stamps have to be purchased with any type of steel wallet product, except those where you slide the letters, but those aren't recommended since they fall out if the casing bends (e.g. under rubble). So I wouldn't really count them into the price, just like the hammer.

A stack of washers (especially larger ones) is extremely solid. I am sure you can even find it in a destroyed house and restore the backup.

What do you think of like doing a simple encoding of the passphrase so that it'll take longer for them to access the content?

I strongly, strongly advise against it. There's a saying that goes something like 'don't roll your own crypto'. There are various posts about it online. In the context of Bitcoin seed backups it's not really because of security concerns, but more about doubts in people's ability to remember what they did one, two or 10 years ago to their seed. Something that seems trivial now (e.g. 'I swap every 4th word with every 5th word' or something), might be completely forgotten mere months later.

I recently ran into an issue where I knew I had a secondary wallet inside a hardware wallet, but couldn't remember how to access it. I knew it wasn't through passphrase and the software didn't show me a second wallet either. It turned out through trial and error, that that wallet used derivation paths to create multiple wallets (without using the standard passphrase feature) and I had completely forgotten about it. It was solved by 'creating' a new secondary wallet in the software (this information is stored on the PC and I had gotten a new one) and the funds were back. But you might not be so lucky with a stack of washers that you applied some random custom 'crypto' to multiple years ago.

[fillippone]

I know the cost section might put a lot of users off the idea of doing this, but ignore the total cost, because the total cost is likely not going to to be anywhere near that. Since, most of these items, people already have especially if they're a home owner. For example, I have millions of washers/screws (including the size required), I have a sledge, gloves, duct tape, hot glue gun, and a micro fibre cloth. That has already reduced the price by 35+ euros based on the OP's pricing. Although, I bet I have a tonne of other stuff in storage that can either be substituted to a degree or already have. For example, the stickers could potentially be substituted.

Honestly, the raw material cost is nothing. 4€ for washers and a few euros for the stamp (you can skip that if in a pinch). Tools should be easily available in any household or can be borrowed by some friend without any weird questions.
All the other stuff like tube, stickers, hot glue etc. aren't needed, so while fillippone went total overkill, I think washers are actually the absolute cheapest way to get a steel wallet backup.

The letter stamps have to be purchased with any type of steel wallet product, except those where you slide the letters, but those aren't recommended since they fall out if the casing bends (e.g. under rubble). So I wouldn't really count them into the price, just like the hammer.

This is exactly my understanding: I wanted to be crystal clear about all the costs, this is re reason why I put that section (apart of being asked this very question in the comments). I went for the "full package", but really, much of the things (even the container) are not necessary, ultimately.

<...>

What do you think of like doing a simple encoding of the passphrase so that it'll take longer for them to access the content?

I strongly, strongly advise against it.
<...>

Agree also on this.
Do not overcomplicate things. Keeping things as linear and simple as possibile is an intrinsic safety measure.

I heard horror stories of people putting HW Wallets (without backup) in a safe box in a bank, then losing the backup and now they forget the PIN. Nice way to lose millions in BTC. Why should you protect with a PIN an HW wallet in a safe box in a Bank? So you can add a layer of disaster!

[fillippone]

Today I saw a tweet from @Alex Bosworth.



Of course he’s referring to the derivation path.

How this could be addressed in our case?

The first solution would be of using the WIF standard, as suggested by Federico tenga in his article.


Another one it would be to use a common wallet to generate the seed, so that funds are stored in a well known derivation.

I didn’t explicitly mention derivation path as I didn’t want to mess up things. Maybe it’s better to state the obvious? “Don’t use any fancy wallet to generate the seed? I should include a derivation washers”? Might be unintelligible  by the person who should get the Satoshi?

[LoyceV]

I didn’t explicitly mention derivation path as I didn’t want to mess up things. Maybe it’s better to state the obvious? “Don’t use any fancy wallet to generate the seed? I should include a derivation washers”? Might be unintelligible  by the person who should get the Satoshi?

If you use a non-standard derivation path, it doesn't hurt to hammer it into another washer. Or hammer the wallet name + version.

This makes me wonder if some people use a very high derivation path to avoid someone stealing their coins: if you use for instance m/44'/44'/1875626591'/0 and even if someone gets your seed words, I doubt they'll ever find your (shit)coins.

[fillippone]

This makes me wonder if some people use a very high derivation path to avoid someone stealing their coins: if you use for instance m/44'/44'/1875626591'/0 and even if someone gets your seed words, I doubt they'll ever find your (shit)coins.

Adding a non standard derivation is adding a potential failure to the system.
So, I am stamping the correct derivation on a wahser: “1875626591“ to stick to your example.

What is the point of storing this strange derivation together with the seed? He who control the seed, controls the deviation also.

But what happens if the washer with the derivation get damaged? 4 numbers become unreadable, because there was a mechanical failure at the store. How are you going recover the funds?

So no increased security, but greater exposure to failures.

As I said, it’s like protecting an HW in a safe box with a PIN: counterproductive.

[dkbit98]

No, I didn't added the Etna suggestion, yet.

Oh nice, there is still hope for Etna special edition

Honestly, the raw material cost is nothing. 4€ for washers and a few euros for the stamp

Are you sure it's still 4€ in all places?
I heard $5 wrench attacked is now renamed to $10 wrench attack because of inflation and price increase
Maybe it's good idea to stock up on steel washers as I am expecting price of metal to go up more in future, and you can always use them in real life.

I didn’t explicitly mention derivation path as I didn’t want to mess up things. Maybe it’s better to state the obvious? “Don’t use any fancy wallet to generate the seed? I should include a derivation washers”? Might be unintelligible  by the person who should get the Satoshi?

I talked many times before and importance of derivation path especially if you are using hardware wallets with BIP39, some of them are totally different by default.
If you only use Bitcoin there is less chance of having issues in future, but add any other shitcoin and you could be having a lot of issues.
Best thing would be to add name of the wallet (also important if you used Electrum for seed generation) on one of the top washer.

[LoyceV]

Are you sure it's still 4€ in all places?

€3,17 per 100! Or €6,10 to go a bit bigger. Or €3,83 if you settle for thinner rings. Cheap stuff

Another thought: how fun would it be to use euro coins to stamp seed words into?

[o_e_l_e_o]

Steel washers are decent at surviving most things, maybe not very high temperatures

You are pretty safe unless they are deliberately exposed to a furnace or similar. The melting point of stainless steel is well in excess of the temperatures reached in a house fire or similar.

What is the point of storing this strange derivation together with the seed? He who control the seed, controls the deviation also.

There's no point storing them together, just as there is no point storing your passphrase alongside your seed phrase. But given that there are more possible derivation paths (by many orders of magnitude) than there are potential seed phrases, it could be used as a "surrogate" passphrase, so to speak, where an attacker would need to know your seed phrase and derivation path. I wouldn't recommend it, though.

Another thought: how fun would it be to use euro coins to stamp seed words into?

Fun maybe, but a quick Wikipedia search tells me the alloys which make up these coins have a significantly lower melting point and tensile strength than stainless steel, so probably not recommended.

[n0nce]

No, I didn't added the Etna suggestion, yet.

Oh nice, there is still hope for Etna special edition

Honestly, the raw material cost is nothing. 4€ for washers and a few euros for the stamp

Are you sure it's still 4€ in all places?
I heard $5 wrench attacked is now renamed to $10 wrench attack because of inflation and price increase
Maybe it's good idea to stock up on steel washers as I am expecting price of metal to go up more in future, and you can always use them in real life.

Yeah, easily. It was 4€ a few months ago at least, for the huge (and thick) 30mm washers I used and stainless steel screw & nut. So it's already 'inflation-adjusted' if you wish. Of course this means it would have been possible to do this for probably 2-3 bucks a few years ago!

Are you sure it's still 4€ in all places?

€3,17 per 100! Or €6,10 to go a bit bigger. Or €3,83 if you settle for thinner rings. Cheap stuff

Thanks for looking up some numbers; your place seems cheaper than mine. Maybe different material. But yeah; the idea is that a pack of 100 washers for <5€ can give you backups for as little as a few bucks each (e.g. if you use washers double-sided). It's supposed to be a cheap alternative to those steel seed plates, however in this and the other discussion thread we saw it even has lots of advantages other than price.

Another thought: how fun would it be to use euro coins to stamp seed words into?

I love this! Just the visualization of (ab)using one currency, reducing it to its material value to store another, much better currency, would really be a piece of art honestly!

[fillippone]

Honestly, the raw material cost is nothing. 4€ for washers and a few euros for the stamp

Are you sure it's still 4€ in all places?
I heard $5 wrench attacked is now renamed to $10 wrench attack because of inflation and price increase

Lol, we all follow the same twitter accounts!



Maybe it's good idea to stock up on steel washers as I am expecting price of metal to go up more in future, and you can always use them in real life.

I didn’t explicitly mention derivation path as I didn’t want to mess up things. Maybe it’s better to state the obvious? “Don’t use any fancy wallet to generate the seed? I should include a derivation washers”? Might be unintelligible  by the person who should get the Satoshi?

I talked many times before and importance of derivation path especially if you are using hardware wallets with BIP39, some of them are totally different by default.
If you only use Bitcoin there is less chance of having issues in future, but add any other shitcoin and you could be having a lot of issues.
Best thing would be to add name of the wallet (also important if you used Electrum for seed generation) on one of the top washer.

Please, I talking about bitcoin only. I don't store shitcoins.
Also, even if I do all correctly, they are going to be worth zero anyway by the time I want to move them out of cold storage.

My third post in the forum:

preface:
I think ALL altcoins are basically worthless.
The point where they differentiate from Bitcoin (protocol choices/hashing algorithm etc..) is actually an inferior one, having been discarded by bitcoin due to security risk/protocol efficiency/ecosystem robustness.
Bitcoin is a huge bet but while I don’ know if in 10 years bitcoin would be worth 1 million or zero (or course I have an idea), I am absolutely sure that in 10 years every present shitcoin (all of them, but bitcoin) will be worth ZERO.
<...>

Another thought: how fun would it be to use euro coins to stamp seed words into?

I love this! Just the visualization of (ab)using one currency, reducing it to its material value to store another, much better currency, would really be a piece of art honestly!

Abusing Fiat money is art: I have a 100 trillion Zimbabwean dollar banknote hanging on my wall, and I am seriously mulling the idea of hanging also a few US dollars.

Stamping euros is a nice idea, but I would stick to something more resistant, both tho high temperature and to mechanical stress.

 

[dkbit98]

Another thought: how fun would it be to use euro coins to stamp seed words into?

Initially I was thinking this is a bad idea but then I looked the content of euro coins ands they are made from at least 75% copper, and depending on banknote there are nickel and zinc in different percentage.
Now, copper has lower melting point than stainless steel but I still consider it a very good and cheap material alternative for bitcoin metal backup.
Note that some countries (with their own currencies) may be using different and lower percentage of copper in their banknotes.
Imagine one crazy thing... using silver coins instead of euro coins to increase value  

Lol, we all follow the same twitter accounts!

I am not following this account, but this is certainly trending in twitter for bitcoin related stuff

Abusing Fiat money is art: I have a 100 trillion dollar banknote hanging on my wall, and I am seriously mulling the idea of hanging also a few dollars.

I have something similar on my wall, as a daily reminder for real value of fiat currency papers.
  

[Pmalek]

First of all, amazing work on this thread fillippone. I can't even imagine how long that must have taken. Respect!

Is it not better for this topic to sit in the Beginners & Help section of the forum?  The method of backing up a seed is crucial for any Bitcoin holder.  The more members see this, the more educated they HOPEFULLY are.

No offense to newbies, but most wouldn't be interested in securing their seed this way. We are still years away from people realizing the dangers of storing seeds in digital formats on your computer or cloud services. Some would probably not even understand what they are reading at all if they saw this thread.

I know the cost section might put a lot of users off the idea of doing this, but ignore the total cost, because the total cost is likely not going to to be anywhere near that.

Not necessarily. A good hardware wallet costs $100-200 these days. The fact that you have to spend a few hours to make it with your own two hands will put people off.

[TheCoinGrabber]

You could encode it if you really wanted too, but depending on your threat model could potentially be overkill. However, to answer your question if someone got their hands on the washers it contains the seed, so they would be able to use it just like anyone else. This basically protects against losing the seeds though various natural threats, for example fires, flooding to degradation of materials. Steel washers are decent at surviving most things, maybe not very high temperatures, but it really does depend on how you store them, hence the container suggested.

Although, if you've got into this much effort, it's probably safe to assume you also have at least some physical security in place to prevent prying eyes. The security labels are a good idea, but effectively if the container has been opened, and therefore the stickers have been torn, you can safely assume that its already been compromised. It's more of a warning that it has been compromised, that something that'll help you save it, if you get what I mean. It doesn't necessarily safeguard your seed.

I strongly, strongly advise against it. There's a saying that goes something like 'don't roll your own crypto'. There are various posts about it online. In the context of Bitcoin seed backups it's not really because of security concerns, but more about doubts in people's ability to remember what they did one, two or 10 years ago to their seed. Something that seems trivial now (e.g. 'I swap every 4th word with every 5th word' or something), might be completely forgotten mere months later.

I recently ran into an issue where I knew I had a secondary wallet inside a hardware wallet, but couldn't remember how to access it. I knew it wasn't through passphrase and the software didn't show me a second wallet either. It turned out through trial and error, that that wallet used derivation paths to create multiple wallets (without using the standard passphrase feature) and I had completely forgotten about it. It was solved by 'creating' a new secondary wallet in the software (this information is stored on the PC and I had gotten a new one) and the funds were back. But you might not be so lucky with a stack of washers that you applied some random custom 'crypto' to multiple years ago.

Thank you for the responses, decided against encoding the passphrase. I'm not even decent with cryptography (sometimes I do "encrypt" texts with tools like cryptii) and considering my history with passwords, I might indeed be unable to decode it properly. Once I do get large enough funds I'd follow the steps in this thread, maybe cover it "starlite" as well.

[PrivacyG]

I just bought the basic stuff needed from my local hardware store.  The cost was way lower than what fillippone has paid for their items.

Got the stamps for $20.  Definitely not the best quality, but they do their job.  12 washers + 1 bolt + 1 nut for less than $1.  Sledgehammer for $10, anvil for $10.  That is $45 for one seed and for every additional seed I increase the total by around $1.

I, for one, consider all the rest to be extra.  And in my case, I already had one sledgehammer, an anvil, some safety labels and gloves in my storage room.  That means my costs would have been $21 had I not wanted to buy an additional sledgehammer and a smaller anvil.  140 EUR seems very expensive.

-
Regards,
PrivacyG

[n0nce]

I just bought the basic stuff needed from my local hardware store.  The cost was way lower than what fillippone has paid for their items.

Got the stamps for $20.  Definitely not the best quality, but they do their job.  12 washers + 1 bolt + 1 nut for less than $1.  Sledgehammer for $10, anvil for $10.  That is $45 for one seed and for every additional seed I increase the total by around $1.

I, for one, consider all the rest to be extra.  And in my case, I already had one sledgehammer, an anvil, some safety labels and gloves in my storage room.  That means my costs would have been $21 had I not wanted to buy an additional sledgehammer and a smaller anvil.  140 EUR seems very expensive.

-
Regards,
PrivacyG

Very nice! Have fun stamping! The prices reflect roughly what I paid as well; $1 per backup means it's pretty cheap to introduce redundancy and / or multisig. Whereas buying 4, 5 'ultra special bitcoin seed plates' for $50 each would quickly get expensive. With this method, it'll be $5 instead.
Did you already print the jig / have it printed or do you intend not to use one? If there are any issues with the file please let me know.

[Welsh]

Not necessarily. A good hardware wallet costs $100-200 these days. The fact that you have to spend a few hours to make it with your own two hands will put people off.

I have faith in people being stingy enough, that they'd rather use their own two hands attempting something, than spend their own hard earned cash. Nah, but in all seriousness, most of these items are common household items, and therefore the final cost is less than a hardware wallet. As suggested too, you don't even need to own these items, you could potentially borrow them, without actually revealing what you intend on using them for.

Also, while a hardwallet can only be used for Bitcoin, and potentially altcoins depending on the one you get. This method could be used for acting as a physical password manager. You could effectively use this for storing any sensitive data you want, as long as you keep them relatively safe from physical attacks. The convenience is lost of a password manager, but I could see some people preferring the physical approach.

Even if its not storing passwords, secret keys for physical security keys come to mind. Since, its not really recommended to digitally store those, but in case of damage or loss of the security key, a physical way of backing them up like this could benefit.

So, when you do compare hardware wallets to this method, the convenience definitely lies with hardware wallets, the security of each could be debatable depending on how its handled, but the potential diversity that this method offers definitely beats any hardware wallet, for typically less money, and a little bit of your time.

[fillippone]

I just bought the basic stuff needed from my local hardware store.  The cost was way lower than what fillippone has paid for their items.

<…>

Perfect!
I bought my stamps on Amazon as my local hardware store didn’t sell any.
Regarding the total money spent, you are right. I bought all the possible item to show the “worst case”, but you were right spending the least possible amount of money!
Do not forget to let us know how you got your jig and of course take some picture of the whole process!

[m2017]

After reading this thread, I came up with the idea to simplify jig. Undoubtedly, n0nce's Steel Washer Backup jig is convenient and useful, but there may be cases when there is no time to search or create jig. In this case, my downgrade (because the design is simplified as much as possible) can perform its function as a template for stuffing letters just as well.

Making. Minimalism at its finest.
1) Take the washer, apply it to the cardboard and trace it with a pencil along the outer and inner circles.

2)  After cut it out it will turn out something like this.

3) Apply the stamp with the back side (or something with the right size) and draw around the contour with a pencil. In 2 places. Choose an interval of your choice (this will allow to have equal spacing between letters). Cut out a hole in the shape of a stamp.

4) Glue small circles, large circles, and then large ones with small ones.

Usage. Even a child can handle it.
1) Insert stencil with a small circle into the hole in the washer. The picture is a rear view.

2) Put the stamp in a square cutout and beat with a hammer. We get a letter. (In my case, the letters are marked with a marker due to the lack of stamps).

3) Turn our template counterclockwise until the 1st embossed letter appears in the left square cutout. Align the position and again beat with a stamp in the 2nd empty field.

4) Repeat as many times as needed.

Nuances.
If there are difficulties with fixing the position of the stamp on the template, then you can use several layers of a large circle (gluing them) and / or using thicker cardboard (thin is easier to cut into shape).

Advantages.
Making from improvised materials, such as cardboard, glue, pencil, stationery knife and scissors. All this can be easily found in almost every home or bought at the nearest store for pennies.

Cheap. Fast. Easily. 100% anonymity (who would ever think to ask what these tools and materials are for?).

You can make a similar stencil on a 3D printer with variations to your choice.

In fact, my version is the inside of n0nce's Steel Washer Backup jig.

I apologize for the quality of product, but I hope the idea was clear and useful to you are.

P.S. Sellers are surprised by the sudden demand and hype for washers. They say they are expected to be in short supply.