Bitcoin Forum

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There are a lot of options for securing your wallet seed, here is a list of some of the options available with a quick feedback of them.

Research Methodology:

• Simplicity is always the best: the more moving parts of the device, the worse in some tests.
• 304 Stainless Steel is the best.
• Most devices pass the resistance test but are bad in temperature and wear, so try to reduce the number of moving parts.
• Devices that can withstand high temperatures are often bad.

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Jameson Lopp has provided the most in depth and thorough testing of these kind of devices. He tested 30 different devices against a 2000 Fahrenheit flame for 10 minutes, 12 hours in a bucket of muriatic acid, and under a 20 ton hydraulic press. You can see the results of his testing here: https://jlopp.github.io/metal-bitcoin-storage-reviews/

Many devices performed very poorly considering their expensive price tag. Generally speaking, the "tiles slotted in to a holder" type devices often resulted in complete data loss. The best devices were ones which involved engraving or stamping the words directly on to the metal plate or device.

when talking about seed this means isn't available for Bitcoin only it could be useful for any cryptocurrency like Ethereum, Litecoin, Ripple and etc. because of hardware wallets like Ledger and Trezor available for many cryptocurrencies using 1 seed only.

I don't see any backup tool like USB disk, paper and cloud. Are you mean that tool isn't safe as backup tools?, I did back up using paper an as long time ago without any problem, low cost and easy to write without knocking hammer on a plate.

IMO

Of course, you can store the seed or private key on a USB stick or on paper/cloud, but OP is showing us only a solution that should be resistant to fire, water, acids and pressure, and metal/steel is used as the base material.

If you were to compare a USB stick or paper wallet with the above, then they have no chance if they are caught in fire or acid, or even water. And when it comes to storing sensitive data in the cloud, it's still the worst solution, even if it's encrypted - what will you do if you lose access to such a service or it loses your data for some reason?

I only ever use paper for my back ups, and I don't feel in the least bit concerned about this. As Lucius points out, paper will obviously perform very poorly when compared to these devices against fire, corrosion, etc. However, assuming that one of these devices is completely safe is incorrect. What if there is an explosion, and your back up is buried under tons of rubble? What if there if a flood or hurricane, and your back up is carried a few thousand meters away? What if it is stolen or otherwise inaccessible to you?

Given that, the only way to be safe is to be redundant. Everyone should be using at least two back ups in separate secure locations. Because I do this, I am unconcerned if I lose one back up due to fire, corrosion, or similar, and so I do not feel the need to use one of these metal devices. Laminated paper in an airtight and watertight container is good enough for me.

It's great, I checked the list, unfortunately some of the devices in the list are no longer available or the company has not succeeded in its development, I will contact him to update that list.
I would also like to point out that the devices mentioned in this list are from steel only.

The reason I just mentioned Bitcoin is that I think 99% of the crypto currency models will not hold up for the coming years, so a small percentage will spend money buying devices to Hodl altcoin.
Ledger and Trezor are Bitcoin & altcoin wallet.
I don't think anyone will pay $ 80 to buy a device for hodling unknown altcoins.


The above list shows that this idea is a horrible. 60% of above devices fail to protect your USB, especially against acids or fire.

If you want to protect your devices and build them yourself, you need to use 304 Stainless Steel, remember to reduce the moving parts.


if you keep more than $ 10,000, spending $ 80 in enhanced protection is not a bad thing.
Use Stonebook (€31,95) with a fireproof case ($29.)

Absolutely. The small handful of altcoins which aren't complete trash can be backed up using a seed phrase just as bitcoin can, so these devices will work fine, but given that the vast majority of altcoins are completely worthless, then the market for steel backups specifically for altcoins is going to be tiny.

If you want to then sure, go ahead, but my point is that making a single back up of your seed phrase is risky, regardless of how durable the material you use is or how well you think you are storing it. There is always something that can happen, and no back up will ever be 100% safe. You should always have at least a second back up stored in a different secure location to your primary back up - this applies to standard important data back ups just as it applies to seed phrases and private keys.

That amount should be much smaller, because $10k is a very nice amount of money in most countries of the world, and since we are talking about BTC, that amount can be increased by x times at any time. Unfortunately, many people think that a $50 investment in a hardware wallet is too much, and the tools you list are too far away to become something that most will start using.


That’s true, and I’ve been checking out some of the tools and some are no longer in production, others are sold out and I have to admit that what caught my attention is unavailable for now.

Those are a whole lot of options, which means we are still not certain on how to properly function as effective and efficient individual vaults or banks. Well, for me I am sticking to the most basic pen on paper, three copies in three different locations.

I totally agree with o_e_l_e_o that the only way to be safe is to be redundant. But not too redundant. I contemplated on making at least 5 different copies but then I realized that the more copies you hide the higher the possibility that one copy is accidentally discovered. You're lucky if the one who comes across it does not have the slightest idea that it could mean a lifetime of wealth, but if that person is also into backing up his/her own seed, he/she must know that this seemingly insignificant list of words means money.

Absolutely. It's a trade off between protection from accidental loss or damage and having one of your back ups being discovered.

There are two main ways you can mitigate this. The first is to encrypt your back ups. This is easily done when we are talking about backing up hard drives or USB sticks, but less so when talking about seed phrases. Indeed, by encrypting it and writing down the random string of letters and numbers you are left with, it kind of defeats the point of seed phrases in the first place, which are to be human readable, easy to copy and recover from with a very low chance of error. Writing down 200+ random characters is much more prone to error than writing down 24 words. You also then need to back up your decryption key, as without it, your encrypted back ups are useless.

The other possibility is to use SLIP39 (https://github.com/satoshilabs/slips/blob/master/slip-0039.md) to split your seed phrase in to multiple parts, with a minimum number of parts required to recover the original seed. Some wallets such as Trezor, and some sites such as Ian Coleman, offer this functionality. This has the benefit of your back ups again being human readable words with a low chance of error.

Copper is also good metal and everyone can make their own homemade backup.
My idea is to buy some copper plates and try to make my own backup, and report will be posted here in bitcointalk.  :)
I don't trust any paper and pen, as I saw it how they fade easy in few years.
Multiple locations is fine, but we are not talking about that here.

Good to read specifics for most metals:
https://jlopp.github.io/metal-bitcoin-storage-reviews/why

Safeseed is one of the cheapest options and it is missing from your list:
https://jlopp.github.io/metal-bitcoin-storage-reviews/reviews/safe-seed/

You're absolutely right, and though I do have a steelwallet that I got in a bundle with my Ledger Nano S, I wouldn't buy that or any others in OP's list simply because they're too expensive for what they are.  I also agree that redundancy is crucial when you're backing up your private keys/seed words.

There is one on Amazon (https://www.amazon.com/dp/B07SNPSTTM/?coliid=I1R95E1P55YRKN&colid=22BTFGIEIX7UX&psc=1&ref_=lv_ov_lig_dp_it) that I actually think is pretty slick-looking, and I've had it on my watch list for a long time.  I don't think I'll ever buy it, but it's aesthetically pleasing to my eye (lol).

Don't buy it!

I don't just say that because of my above statement that I do not believe this devices to be necessary. Rather, this was stress tested by Jameson Lopp, and much like other devices which feature a "tiles slotted in to a holder/template" design, it performed incredibly poorly. The fire stress resulted in almost complete data loss, and the corrosion stress test resulted in not just complete data loss, but complete loss of the wallet entirely as it disintegrated.

https://jlopp.github.io/metal-bitcoin-storage-reviews/reviews/ellipal-mnemonic-metal/

Copper is a good conductor of electricity and heat. It is malleable, I don't know why I chose it, but taking the tests would be fun.
I will add it later, but it failed a plantation failure, I am planning to add some devices away from the iron and steel parts.


As I said before, if the moving parts are not tight and the design is stiff, the device will fail. Do not waste your money.

https://i.imgur.com/RUTR7a3.png

Jameson Lopp made Round IV report for Metal Bitcoin Seed Storage Stress Test:
https://blog.lopp.net/metal-bitcoin-seed-storage-stress-test-iv/

Several seed backup tools included Seedplate, Cryptoetch, Cypherwheel, Hodlinox Single Plate, Tjernlund, SteelKi, SAFU Ninja.
Best performed are Cryptoetch and Seedplate and both are priced around $40

A couple of brand new designs in there which makes it interesting. The Cryptoetch looks very interesting with its electrochemical etching process. I poked in to it a bit more and found a tutorial video on their website here: https://cryptoetch.com/. Certainly a cool and novel design, but given how well various "stamping" products hold up, particularly the Seedplate, it seems maybe a bit unnecessary to me.

The Safu Ninja again looks cool, but introduces the problem of the plates getting mixed up should the nut at the end of the screw fail or come loose, which the plate designs do not have. Given the recent data breach from Ledger, it is absolutely a good idea to avoid giving away your details if you can, but if you can go to a hardware store to pick up those components and a stamping set, you can just as easily pick up a small piece of stainless steel, which is what most of the plate designs are made of.

I do plan to go in my local hardware shop and buy several stainless steel and copper plates for my personal testing use, all thanks to Jameson Lopp  ;D
They are very cheap and I can also order them online.

Memory is fickle. Unless you regularly practice and recite your seed phrase you will forget it, and most people are also bad at forming habits. Even if you are in the minority who will regularly practice, there are a thousand and one reasons you could forget it instantly, from a mild blow to the head following a simple accident or fall, to an illness or infection. We are even seeing neurological problems in people who have suffered from COVID, even in otherwise mild cases.

This paragraph is just wrong. A back up stored in the same physical location as your wallet is not a back up at all, for precisely this reason. Off site back ups are a must.

If you want to memorize your seed phrase for fun, go ahead, but you should not rely on it as a back up method, and you should still use multiple secured paper back ups.

Maybe it can be just for fun, but in that case another possible vector of attack comes to my mind - and that is that such a person under the influence of some drug or hypnosis actually reveals a secret to the attacker. The human brain is an extremely complex device, but I definitely agree that we should not rely on its memory when it comes to very sensitive data.

And how many times in their life do you think they've said their name out loud in person or over the phone, written it down on a form/paperwork/application/document/school work/college work/university work/etc., typed it in to a website/email/sign up/log in/etc. How many times is someone doing the same thing with their seed phrase? The two are not comparable.

Everyone should have a back up method which does not depend on them knowing anything or even being present. How else are you going to pass your bitcoin on when you die? The easiest solution is to simply tell a family member.

As I said, if you want to remember your seed phrase go ahead, provided you also have a paper back up. I work with people on a daily basis with neurological impairment from a variety of reasons, many of them young and fit individuals who have suddenly and without warning suffered a life changing event.

How do you guys stamp the seed phrase into one of these metal backup plates?
I tried it once so far with a piece of wood as support and in the end, the plate was completely bent inwards.
Does it work better with an anvil or other hard metal piece as support?

I ended up hammering it straight by bashing it on the back side, but it wasn't so elegant.. ;D

Yes, use wood as support.
there is a special method how to stamping letters for a good result. I have experience as a mechanic. in the beginning, don't stamp with perpendicular (90°), use with an angle 80°-70° first. when letters are visible (maybe isn't perfect - blurry) do it again with an angle of 90°. If the plate has a greater carbon content you have to stamp it more than 2 times.

If the plate is thin, don't hit too hard, do it slowly step to step with the method above.

Thanks for the advice, I'll try that way next time! What speaks against using an anvil as support?

Why not just etch/engrave your words rather than stamping them? You can get an etching pen for 5 bucks on Amazon or a local hardware store, or just go old school and get a scrap sharp piece of similar metal. No issues with bending or deforming the plate, but you just need to make sure your writing is clear and legible.

What metal are you using? Make sure it is both thick enough and not a malleable metal. Stainless steel and titanium are good choices.

Having some kind of "steel" or fire/crush/water-resistant medium to store your seed is fun, but I am afraid these types of products will discourage people from having off-site backups, which is what really provides security that people will not lose access to their seed.

For many people, a wildfire will mean that a location will be inaccessible for months at a time, and there is the risk that houses will be looted. The same is generally true for hurricanes/severe floods. A severe flood may also physically move a medium documenting a seed, and it may be difficult, if not impossible to locate the medium, even if it survives.

IMO, it would probably be most appropriate for most people to keep a paper copy of their seed in a fire safe in their home. They should also keep a separate copy in at least one off-site location. If the area they live in has a particular high risk of flood and/or fire, the off-site location should be particularly far from their home, idealy inland.

What kind of metal material are you using for seed plate?
It should be something like stainless steel or copper, and you can ask for best tools to do it in local hardware shops that sell metallic parts and tools.
One interesting idea is using metal plate and punching holes in binary form that is cheaper and faster than using full words, and even if someone finds them there is less chance he will know what that is.
You can find instructions below written by jakob6102:

https://i.imgur.com/rV5jcoG.jpg
https://github.com/jakob6102/seedcard

I don't know, I thought engraving always looked very crooked and it doesn't go as deep, which makes me think stamping holds up longer.
But I might pick up an engraver to try next time.

The metal I used so far was 1.5mm stainless steel.

I think it depends a lot where you live. In my region, there is little to no risk of the events you mentioned. I'm still a big proponent of off-site backups.
But especially for those, it's nice to have a tamper evident seal, be it a steel wallet that offers this feature or just a paper wallet stored in a ShiftCrypto tamper evident seals (https://shiftcrypto.shop/en/products/tamper-evident-bags-27/) for example.

I really like this idea, in general anything that can be store-bought and doesn't directly indicate what you're trying to use it for. As opposed to buying a purpose-specific 'device' that may be tracked through post etc.

There is also the option of stamping words onto washers and storing them on a screw, but for that I need smaller stamps or big washers.
I'll try these options as well in the future for sure!

That's probably your issue there. If you take a look at a variety of proprietary stainless steel back up products, the good ones are usually much thicker than this.

Coldbit - https://coldbit.com/product/coldbit-steel/ - 4mm
Cryptoetch - https://cryptoetch.com/ - 5mm
Cryptotag - https://cryptotag.io/ - 6mm

You can always make your own by screwing a second stainless steel plate on to the one which has your words stamped/etched on it, obviously obscuring the words, and then affixing a tamper evident sticker across the two plates, or drilling holes in at least 2 opposite corners and passing through tamper evident wire seals or something similar.

Thanks for the recommendations and ideas, I’ll surely try a bunch, it’s always fun to have more backups ;D

I got one of those steel stamping blocks. It's a quarter inch thick, so ... but I haven't gotten around to electrically etching it yet. It's like 2 inches by 2 inches square and 0.25 inch thick. I also found some galvanize metal plate somewhere, I'll have to clean that up then do some salt water etching on it too.

Side note to all of this but keep in mind a lot of "fireproof" safes are not.
If you search google / youtube for fireproof safe failure you can see a lot of them.

Which brings us to the point. For a lot of these metal plates for the god forbid house fire that destroys everything having a real 1st layer of heat defense is better then having a safe that fails in 5 minutes. Also, with some of the wildfires in CA and other parts of the world having real protection is sadly becoming more and more necessary.

Just something to think about.

-Dave

Those bags are useless, and will provide zero protection.

First of all, someone with physical access to one of those bags could look at what is inside the bag to obtain the seed stored in written format.

More importantly, once someone has access to private keys belonging to a 3rd party that they have compromised, they are going to quickly move the coin being secured by said private keys. This means you will likely realize your private keys have been compromised when your coin has been moved via transaction(s) that you did not sign. Or, you might arrive to the location of your off-site backup, and find the tamper-evident bag very clearly opened, but upon inspection of the blockchain, will find your coin was moved a long time ago.

Most fire "proof" safes have a specific rating regarding the temperature they can protect against, the specific types of contents they can protect given a specific temperature, and the amount of time they can protect said contents at said temperature.

If your safe is rated for paper, but you have a USB drive inside the safe, there will be problems for all the contents inside your safe. Ditto if the safe is rated for 500 degrees, but the fire immediately outside the safe is 550 degrees.

They provide zero protection, but they are not useless.

Take the situation where you have a seed phrase backed up in one location and a passphrase backed up in another. If you notice that your seed phrase's tamper evident bag/seal/whatever has been broken, then you will know that an attacker has your seed phrase and may be attempting to brute force your passphrase, and you will move your coins immediately to a new wallet. Without a tamper evident bag, you would not have this knowledge. You will also now know that that particular back up location is not secure and you will stop using it, information you wouldn't otherwise have.

No single back up I have is enough to steal any coins from me, but I definitely still want to know if any single back up has been accessed by someone who isn't me.

I don't know if you saw what happened in Greece this year, but it was crazy with wildfires more than ever before I think.
Having regular paper backup is just not good enough if you want to have piece of mind that your backups won't burn in flames.

They are not meant to offer any protection, they should just to tell you if the bag was opened or not, something like sealed envelope, when you break the seal you know that content inside was compromised.

I don't know if anyone is familiar with this, but I found one interesting project called entropy seal for tamper-evident packaging, it is a jar with particles for storing any sensitive physical goods.
I am not sure if they are selling it yet but it is interesting concept, one thing I don't like is that some phone app must be used for capturing and comparing image,
so I wonder what happens if app is dead or not supported in new phone...

https://i.imgur.com/fXAej7i.png
https://www.entropyseal.com/

I've read some time ago about using metallic nail polish, or glitter nail polish. There's probably a link somewhere, let me look for it.

https://boingboing.net/2013/12/31/glitter-nail-polish-is-the-bes-2.html
https://trmm.net/Glitter/
https://lifehacker.com/use-glitter-nail-polish-to-make-your-laptop-tamper-proo-1493599646
http://www.kristovatlas.com/improving-tamper-evidence-for-hardware-wallets/
http://blog.ssokolow.com/archives/2017/04/08/home-made-tamper-evident-security-seals-for-kids-and-adults-alike/

I found a few. I'm sure you can find more. The last one doesn't use glitter nail polish but has a similar idea. I think I prefer glitter nail polish.

I'd use a thick paper envelope, seal it or glue it, then paint some nail polish on the envelope or sign it with a marker. If you have some sort of other plastic or metal container, you can get creative as well.

The app is probably a "blink test" to compare the images. You can probably store those images anywhere you usually store them, google photos, amazon photos, drop box, emailed to yourself, or even uploaded to your own website.

You ultimately need to store your entire seed, including any passphrase in (an) offsite location(s). Otherwise, you risk losing access to your coin.

If your security model includes storing portions of your seed in various offsite locations, a tamper-evident bag may provide minimal additional security. Like I mentioned above, these bags are typically transparent, so an adversary will likely not need to actually open the bag in order to see what is inside. It is also probably trivial to do things such as fold/unfold items inside the bag, as well as open things such as an envelope.

I am also not sure how often most people access their off-site backup location. I think for a lot of people, this is fairly uncommon, especially if the location is far from their home.

The purpose of a tamper-evident bag is really to provide assurances that the content inside the bag has not changed. This is really not an important question when restoring from a backup.

As I mentioned above, it really tells you fi the contents inside a bag have changed.

Pretty cool concept. Obviously, if your entire seed is compromised, this will not do much good.

I'd echo PN7 in saying this is a very cool concept. I'm not sure I have any use case for it, but I'm sure some people will. Quick question for anyone who can answer since I have no idea - how feasible would it be for someone to remove the bottom of the plastic container (I don't mean unscrew the lid which would obviously mess up the beads, but rather cut/melt/whatever just the bottom of the container), access the contents, and then attach a fresh piece? What about to do so in a way that it wasn't immediately obvious that it had been done?

So I can use a non-transparent bag. Or put the seed phrase inside an envelope - either they open the envelope inside the bag, in which case it is obvious my seed phrase has been accessed, or they have to open the bag to replace the envelope, which gives the same result.

Not if you are using passphrase or multisig setup.
Your seed phrase can get compromised without you even knowing it if you don't have some tamper-evident solution like this.
Someone can find your seed phrase, copywrite your words and put your plate or paper in place like it was before, you would never notice it on time.

It would be impossible to do this without owner noticing that bottom was tampered with, so you would probably get a worse results then if you just open and remove the top lid.
One thing that could happen is that someone clones or 3print identical plastic box, but easy way to protect against this would be to make your box custom and unique only to you.

If you have a tamper evident transparent container, and it contains an envelope with tamper evident seal / signature / glitter nail polish, then you'll know if anyone opened it, but while it's not open, you'll also know that no one can read whatever is inside the envelope. Just wrap it in more pieces of paper with random scribbles like "security envelopes".

I'd probably use a small tin can and screw it together, then put some 2 part epoxy on it, then glitter and other creative stuff. You'll have to break it to open it, and it will be obvious.

As I noted in my above post, you ultimately need to store all information required to access your coin, including any passphrase, and additional keys if using multisig. You can store this information in multiple places if you so choose.

It is possible to see through some envelopes by holding it up to a light. There is also more advanced technology that can see through darker paper.

Tamper evident bags are really not intended to prevent an observer from looking at the contents inside the bag.

Agreed that envelopes and even thicker ones or darker ones may still be readable, but could you possibly insert another thick paper in there to make the original paper unreadable without opening the envelope? Or even insert small metal foil so no one can shine a light through? Your potential adversary would need advanced technology and I'd wonder if it may be worth it, or they would rather just open it anyway (and then you'll know someone opened it.)

You could have other forms of security to find out if the site has been tampered with or if anyone else has been to that location, depending on specifics. Cameras, or even other low tech solutions (hair stuck to the door, floor patterns of scattered rubble or whatever, dust?)

Sure, there is a lot you can do to try to ensure that you are aware of a compromise when you visit your offsite backup location.

The problem with the above is that it is generally unusual for someone to visit their offsite backup location, and that most people store all information needed to access coin in a single offsite location.

This will only result in negative outcomes. You will generally not know for a long time vis your tamper evident bag, they your backup has been compromised. There is also the potential that you will have multiple offsite locations compromised and you will not realize it. Or you might sacrifice physical security in favor of using a tamper evident bag that results in your private keys being stolen.

Which is exactly where a tamper-evident set up is useful. I don't want someone to be able to compromise one of my back up locations and for me to have no knowledge of it. Some of my back ups are for cold storage coins I haven't touched in years and don't plan to touch for years. Do I really want a period of 10+ years with an attacker knowing my seed phrase and attempting to brute force my passphrase, find its back up location, or both, and me having absolutely no knowledge that that is what is happening? Of course not. Even in your hypothetical situation of me only checking my back ups very rarely, a period of few months before I discover the breach is far better than not knowing about the breach at all.

Just don't make it super-complicated and don't go crazy with epoxy that would make it impossible to open the can :D
Maybe one more step would add extra complexity but I like the idea of using binary form for seed words, so that most people wouldn't even know what those dots really are.
https://github.com/jakob6102/seedcard

Well you need to store everything in this world somewhere, and I would not count on my memory and brain to remember anything important.
You are obviously not going to keep all that in one place, passphrase should always be ins separate location, but what if you forgot where you put all those stuff?
Alzheimer's disease and other neurological disorders are getting more common, and our memory is getting worse and more full with age, that is the case with all hard drives  ;)

Eh, yeah, just use the epoxy to seal it and make it tamper evident, not open-proof.

That binary one is a new take. Previously I was thinking of using 4 digit octal, or 3 digit hexadecimal numbers stamped or etched. I end up deciding I prefer to just etch the whole word. Still a work in progress but there are a few videos on youtube showing how to electrical etch / engrave stainless steel.

Everyone has a finale budget for security. I think it would be better to invest whatever you would spend on the tamper evident bags on a more secure/better safe, or other equipment that will prevent an adversary from accessing your seed.

If an adversary is able to access one location storing a portion of your seed, they will likely make a serious attempt to access your other locations. I think it is probably reasonable to expect them to do so within half the interval that you would normally access your off site location.

If you insist on having something in place that alerts you of a potential compromise, I would suggest something that alerts you right away. I think a tamper evident bag is really not much more than a false sense of security. Given enough time, an adversary may even be able to replace the bag, making it appear there was no compromise.

Can't disagree with that. You know these doomsday preppers with hidden bunkers have CCTV or cameras... So they know if anyone has been in the area or tried to get in (or actually got in.) You could have something solar powered that pings you all the time and if it either losses power or the door to your little container has been opened you'll know within a minute. (your device would need to have mobile data or internet or something maybe, or at least ability to send some sort of message.)

My ideal location with be some bunker with a relatively long corridor that they must go through and you have something watching that path. You're also making some assumptions that nothing is going to dig in from the sides or from underneath it, but you can probably have sensors for that too.

As @dkbit98 multisig is probably the best. Setup a 2 of 3 wallet. Have all three seeds in different locations, sealed in different tamper evident ways.
Check on them often. Someone would have to compromise 2 locations, 2 different ways without you noticing before getting to your BTC.
For more fun, add a 4th location with a seed that has nothing to do with anything.

-Dave

I would add that probably best and cheapest way is to make your own DIY backup seed phrase, you just need to purchase stainless steel flat washers and screw with nut that all cost just few dollars.
You would also need to 3dprint or buy plastic Jig, and you need to have metal stamping tool with letters and numbers, but result is amazing very durable backup, and people probably won't suspect what you are using this for.
It may take some time to create this but you can customize, and it's cheaper than all  other listed methods.

https://i.imgur.com/0c1gQ1a.jpg
https://www.econoalchemist.com/post/backup

They survived both tests quite well. I wonder what would have happened if he continued with the heat test for a few more minutes. Some of the flat washers suffered visible damages. #8 and #16, for example. It should be mentioned that both of those flat washers got some of their clarity back after being soaked in salt water.

If your backup is exposed to that kind of temperature for much longer in a real life situation, you have other problems that might need more attention. Normally, with stuff like this, they should be stored inside some waterproof bag, bottle, ziplock or something and that whole thing is buried somewhere it is unlikely to be subject to intense heat.

OT: John Wick stores his gold coins in the basement under concrete.

You're right, it's indeed the cheapest one but I'm not so sure if it's the best one. I wish he ^{[@econoalchemist]} would've included the temperature at peak ^{[he had a thermometer]} and the exact time when it reached that level ^{[the video appeared to be on x3, so it was probably less than 3 minutes at around "800 - 900°C (https://archive.fo/R8BcZ#selection-707.8-719.12)"]}.

But if there was a way to not include the seed numbers, it would've been a lot better.
^{- Sorry for nitpicking [I do know it's needed to not mess up the order].}

For just a few more minutes, I think we would still be able to read the letters but anything beyond 30 minutes ^{[assuming that the temperature rises gradually]} would probably result in those flat washers melting fast ^{[Stainless steel melting points (https://www.thyssenkrupp-materials.co.uk/stainless-steel-melting-points.html)]}.

Continuing OT, if someone steals then from him, he is going to get them back.

Seriously, was thinking while driving home. Why was using stainless steel even a thought for the engraved plates, instead of, as o_e_l_e_o said and using titanium or other stronger metals.
For the punched ones, I get it.
But you are never really going to get enough heat to melt titanium or have an impact strong enough to really damage it. Just wondering if it is a case of, "that's what it is" or if there was another reason.

-Dave

Probably due to cost. Titanium solutions do exist, like: https://cryptotag.io/products/zeus-starter-kit/. It costs 130€.
I am not sure if engraving holds up as well as punching in extreme conditions simply due to 'modifying' the material less, if that makes sense.
Engraving a word is like a very, very shallow stamp of it, so I prefer stamping. Lopp didn't comment on it much, but I found visually, that the stamped letters held up better.

I have to say, engraving looks often quite bad (it's not as easy to hold such a thing steady as when using a pen :D) and stamping isn't much better. The letters are always equal, but can come out crooked, too high / low etc.
While you might think it's irrelevant, I think it's very important for seed backups to remain legible after a long time and maybe extreme conditions as well.

So I like the idea of just punching holes, like in binary format or like in the CryptoTag Zeus which uses 'BIP39 numbers' (indexes: https://cryptotag.io/bip39-list/) instead of BIP39 words: https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt

It's a trade off between durability and cost. Stainless steel isn't quite as good as titanium, but it is more than enough for almost everything we care about and it is significantly cheaper. All common alloys of stainless steel have melting points >1400 Celsius, while titanium is around 1650 Celsius. Building fires are generally in the range of around 800-1100 Celsius, so both will hold up fine. Titanium is only a couple of places below 304 stainless steel on the galvanic scale (the lower it is the less reactive it is), so in terms of corrosion although Titanium is slightly better the difference will again be negligible for our purposes. The difference in yield strength equates to something like 13 tons of pressure per square inch for stainless steel and 16 tons of pressure per square inch for titanium, both which will withstand almost all building collapses or similar.

So yeah, if you can afford titanium then go for it, but you'll also be fine using a thick enough piece of stainless steel.

I think it's best bang for your buck. 304 stainless is better in this regard. 316 or 316L for saltwater, but if you are concerned about that I would just use 304 and put that in plastic container. Then bury it where it can't get burned. You can throw in some oxygen absorbers or fill the container with dry ice (co2) or argon gas. I would just wrap the whole thing with bubble wrap, then bury it somewhere, then pour concrete over it.

Now if it's in a tall building, that's gonna be a problem.

I think you are making a strong argument against titanium.

There are very few scenarios in which a titanium seed backup will survive when a stainless steel backup plate will not.

You control the location of where the backup plate will be stored, so you can simply keep your backup in a location in which for all intents and purposes, the backup is not going to be subject to conditions that would cause the plates to be unreadable. Sure, there might be a situation in which you are incarcerated for an extended period, the conditions of the subject location change in a way that results in a fire melting a stainless steel plate that would not melt a titanium plate, but the odds of all of these happening are really effectively zero.

I would also repeat my argument that budgets are finite. If you can "afford" titanium, you should buy stainless steel and use the difference in cost to invest in additional/other security measures.

I was thinking something along the lines of storing your backup in a safety deposit box that contains a device that detects light that has the ability to alert you if light is detected. The device could have a long battery life and may be attached to the back of the container inside the safety deposit box.
I understand you live in a very different part of the world than where I live. I think it would be interesting to one day visit your country as a private citizen in possession of a modest amount of cash. I also understand you are in a unique position for people in your country and might be able to protect private keys better than most other people in your country because of your unique situation.

Well, it depends. Perhaps you have enough budget to buy all the security measures you want. Perhaps your back up plan is to stamp your seed phrase on a piece of metal, and then screw that metal (face down) on to the concrete foundations of your house under your floor boards or in your basement, in which case there is nothing else to spend your budget on. Perhaps someone can source some scrap titanium for a very reasonable price, or even have some left over from one of their own projects. But yes, as I said above (and as has been shown by Jameson Lopp's stress tests), stamping or engraving on stainless steel will be more than enough for almost every situation.

When considering the cost of tamper evident bags or seals, these can be bought for less than 5 bucks, which is not enough to make a meaningful difference to the quality of a safe, the grade of metal you are using, a remote alert device, etc.

Check out the Haven app, for android. It uses any android phone and it's sensors. Most phones have cameras (for light) and acceler---xxx the GPS thingy and a magneto-compass thingy. Whatever it's called, it can detect light or if the phone is moved.

Problem is battery life. Even if you attach a large power bank, it will eventually die.

Can probably use the cheapest Samsung J6 or something $100 phone, put it in ultra-low-power mode ... safety deposit boxes are usually dark, you can probably place it in some other location that has a window for sunlight and use a solar charger. Charges the phone during the day, runs on battery at night ... if it's within range of cell tower you can have it on the lowest prepaid plan and you'll maybe get an alert if something moves.


I've moved quite a bit away from there, it's not a secret where I am, but rather not make it public, OpSec and all that. There are local exchanges and almost like El Salvador some merchants accept bitcoins, (some accept altcoins / shitcoins / erc20 tokens) ... I don't have access to my imaginary bunker, but something I'd like to personally build where ever I end up living.

I do keep a house in that country since it was cheap to buy and maintain. It does not have a basement, but it has a small back yard, so I can bury something there. Actually, it would make more sense to just keep whatever backup seed metal plates inside that house. ... hmmm... 3rd world problems eh..

BTW, don't bring too much cash, just enough, the rest you can bring as bitcoin and exchange that once you are in the country. Actually, you can probably bring in $10k USD cash no issues and then use local money changer or banks to convert to local fiat money. If you're staying longer than 90 days, you may need a visa or something. Otherwise, tourist visa on arrival is good for about that long.

I think this topic deserves a little bump

Side comment, but lets leave it as Dave knows for some reason....

With the seed plates that use a punch tool, be very carful as to the strength & quality of the tool and the force you are hitting it with as you are holding it.
And perhaps a bit of eye protection in case the punch tool shatters into about 73 billion pieces. 

Just saying I'm an out of shape computer nerd so someone a bit stronger may have some experience with this too....

-Dave

It deserves an update as well ;)

- Some of them have outdated links and prices.
+ Coinplate - a new, ultra durable Seed Phrase Backup solution (https://bitcointalk.org/index.php?topic=5394608.0)

• ^{I do know there are more, but this is the only one that I could find with an announcement thread in here.}

I hope nothing happened to both of your eyes and hands ^{[this is the first time that I'm reading something like this]}, but how hard did you hit the punch tool?

Not hard at all. But, lets be blunt it was, as have been most that I have seen, a cheap made in China piece of crap.
I'm sure there are some seed plates makers that do not give you an automatic one give better manual ones.

But the last few generic ebay / amazon ones have really sucked.

<shrug> It is what it is, when you are getting something like this shipped to your door for under $15 you don't expect quality or durability of the plate or the tools. But it's still better then paper.

-Dave

i would like to add the 'recovery seed BTC plate' from user willi9974 (https://bitcointalk.org/index.php?action=profile;u=216582) to your list.
this stainless steel plate is available in a 6mm thickness (weight of 450 grams) or a 4mm thickness (weight 310 grams).
there is also the possibility to use this plate on both sides (with a 24 seed). the whole seed matrix is very detailed lasered on the plate.
a complete stress test was done by Jameson Lopp with the plate. in the following link you can see the results and some pictures: https://jlopp.github.io/metal-bitcoin-storage-reviews/reviews/willi-recovery-seed-plate/ (https://jlopp.github.io/metal-bitcoin-storage-reviews/reviews/willi-recovery-seed-plate/)

the whole plate is made of a v2a stainless steel. it is an acid resistant 18/10 chrome nickel steel, which due to its low carbon content after welding is intercrystalline resistant for plate thicknesses up to 5 mm even without subsequent heat treatment.

original german thread: Edle Edelstahl "Recovery Seed BTC Plate" (https://bitcointalk.org/index.php?topic=5319811.0)
english thread: Stainless steel Bitcoin Recovery Seed Plate (https://bitcointalk.org/index.php?topic=5323755.0)

Just because I was watching Air Disasters https://www.smithsonianchannel.com/shows/air-disasters and saw them X-Rays and a few other things to look for damage that is not visible to the eye inside of parts. Has anyone tried to look through seed plates to see what can be seen without actually opening them?

Kind of James Bond / Mission Impossible thing where they get your seed plate, scan it, and then put it back without you knowing but I was just wondering if that is even a possibility.

Not a big worry and I'm going with probably not, but you never know.

-Dave