n0nce's Steel Washer Backup jig (customisable)

[fillippone]

privacy when buying the materials (preferably in store, paid for with cash, of course ).

This is something I thought about.
Of course the most difficult part was getting the 3D printed jig. But I was lucky enough that the person didn’t know anything about bitcoins (or pretended to).
We will see…

For best opsec, I think it can even make sense to buy a small 3D printer just for the purpose of printing a few of these jigs, since a printer can cost less than hardware wallets. You can also then resell the printer at half price if you're really sure not to ever need it again.

From the few iterations o had with people printing 3D objects, and people preparing 3D files (ehehe) I had the idea the whole 3D printing process is still to clumsy, prone to errors, trial and error, mishaps and other accidents to be considered so “safe” to make such an investment.
Going forward, something definitely doing going forward.

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[n0nce]

From the few iterations o had with people printing 3D objects, and people preparing 3D files (ehehe) I had the idea the whole 3D printing process is still to clumsy, prone to errors, trial and error, mishaps and other accidents to be considered so “safe” to make such an investment.
Going forward, something definitely doing going forward.

Well, it's not a big investment is the point I'm trying to make. You can get a working, small 3D printer for probably very close to 100€. But of course it will take time to build, set up, get into the whole process for sure.
Otherwise you can also always stamp onto washers without any jig. It's just a little help...

[dkbit98]

Well, it's not a big investment is the point I'm trying to make. You can get a working, small 3D printer for probably very close to 100€. But of course it will take time to build, set up, get into the whole process for sure.

3D Printer is a great investment but I am not sure you can find decent machine for around 100 euros (if I am wrong about it please post some links).
Maybe this cheap machine can work for printing jigs for steel washers or for some simple objects, but I don't think it can print more complex objects.
What I would really want to have is 3d scanner, because it's much harder to make 3d model than to print it, and scanners would help a lot with this.

[n0nce]

Well, it's not a big investment is the point I'm trying to make. You can get a working, small 3D printer for probably very close to 100€. But of course it will take time to build, set up, get into the whole process for sure.

3D Printer is a great investment but I am not sure you can find decent machine for around 100 euros (if I am wrong about it please post some links).

Of course, for $100 you don't get the nicest looking and highest accuracy prints, but it will probably work just fine for a bunch of jigs.
Can an $80 3D printer be any good? EasyThreed K7 Review

For like 150, you do already get sturdier, larger machines definitely.

What I would really want to have is 3d scanner, because it's much harder to make 3d model than to print it, and scanners would help a lot with this.

3D scanners are unfortunately really bad. The idea is cool, but as of today, they're either super expensive (and still require CAD touch-up work) or very bad and not suited as an alternative to designing something by hand. The perfect application for a 3D scanner would be producing a spare part for something, but even in those cases it's faster and more accurate to use some calipers and design the part in CAD.

[dkbit98]

I found interesting project called SeedCapsule that can be useful for people who are using steel washers for holding seed words backup.
Stl files for 3d printing can be found on their github page, and what is interesting that you can make your backup tamper evident with this method.
Capsule stem must be broken to take out steel washers, and it is locked with a twist before that.
I am not sure if it is compatible with washers that n0nce used in this topic, but other people may use it also.


https://orange.surf/seedcapsule/

[LoyceV]

what is interesting that you can make your backup tamper evident with this method.

That looks nice! But to make it tamper proof, you'll need to make sure you recognize the exact version you created. If someone can just print his own SeedCapsule to replace yours, you may not notice it.

[dkbit98]

That looks nice! But to make it tamper proof, you'll need to make sure you recognize the exact version you created. If someone can just print his own SeedCapsule to replace yours, you may not notice it.

That is true, you can always make your own custom made details that can't be printed and duplicated exactly.
It's not that hard if you have your own 3d printer, to add specific color mix or something similar like that, maybe editing stl files and making it unique.
Just let your imagination go wild.

[fillippone]

what is interesting that you can make your backup tamper evident with this method.

That looks nice! But to make it tamper proof, you'll need to make sure you recognize the exact version you created. If someone can just print his own SeedCapsule to replace yours, you may not notice it.

I have been working on this since a while (more to come later on this thread).
Making your seed tamperproof is a crucial aspect of the whole process. I found a solution, but I am far from satisfied from that.
Keep in mind that ideally many years can pass between the creation of the backup and his usage. So verification of the taper isn't trivial.
Regarding to this:

It's not that hard if you have your own 3d printer, to add specific color mix or something similar like that, maybe editing stl files and making it unique.
Just let your imagination go wild.

You have to "remember", or communicate to the third person. Which colors/pattern used for that specific seed. It is an added layer of complexity.


I'd be better to speed up and disclose my own method.
But damn... I am busy IRL.

[dkbit98]

Making your seed tamperproof is a crucial aspect of the whole process. I found a solution, but I am far from satisfied from that.

Any tamperproof method is better than none, but let's not think that it is perfect method for protection.
Using stickers is probably cheapest way when you are using seed phrase backup on paper and custom made envelope that can't be reproduced so easy.
I know some people are selling more expensive tamper evident plastic bags that can be used for coins or for crypto, but  think this is waste of money.
Interesting free idea is taking different colored grains and legumes in tight box container, mixing it all up and taking a picture of that mix.

[fillippone]

Interesting free idea is taking different colored grains and legumes in tight box container, mixing it all up and taking a picture of that mix.

Sorry, I am not smart enough to understand how this should work. Also, you don't need to take care of a seed, but now you need to take care of a picture?

[o_e_l_e_o]

Sorry, I am not smart enough to understand how this should work. Also, you don't need to take care of a seed, but now you need to take care of a picture?

Take a transparent plastic food container.
Fill it half full with a variety of rice, grains, legumes, seeds, confetti, different colored ball bearings, etc.
Place your seed phrase inside.
Fill the rest of the box with more of the above until it is overflowing.
Force the lid on, sealing everything inside tightly so it can't move around.
Take photos of the box from a variety of angles.
Hide the box.

Now, when you go back to retrieve the box in the future, you can compare the photos you took before to how it looks now. If anyone has opened it to access your seed phrase, all the grains or whatever you used will have moved around and will look different to the photos.

[fillippone]

Now, when you go back to retrieve the box in the future, you can compare the photos you took before to how it looks now. If anyone has opened it to access your seed phrase, all the grains or whatever you used will have moved around and will look different to the photos.

If I lose the picture, the proof is not effective. If somehow the box tumbles or it is moved in a “wrong way” the tamper proof would reveal a false positive.
If someone wants to check the integrity without the picture, he simply cannot.

Mhh I appreciate the design simplicity, but I don’t like it.

[dkbit98]

Sorry, I am not smart enough to understand how this should work. Also, you don't need to take care of a seed, but now you need to take care of a picture?

It's not like you have to keep this image safe from terrorist or hackers, because nobody knows why you are using regular photo of grain and legumes.
There is no way you can get false positive for tamper break if you do it correctly, this is not some rocket science and you don't need lot of time or money to make it.
I remember that I saw easy instructions how to make this yourself but I can't find it right now.
Guys from EntropySeal are doing something similar:
https://www.entropyseal.com/

[fillippone]

https://www.entropyseal.com/

Thanks, now there is another piece of gadgetry I do want.

What concerns me about the picture is not that terrorist or hackers are going to crack it. But that it simply get lost,  because the person responsible for hodling this loses access, a tech failure or other common mishaps can happen to a digital good over the years.
My idea is that the tamper proof should be locked inside the box, so that it is a self contained “circular reference”.


Since we are here, a preview of my upcoming test of n0nce jig:



I added to the washers a couple of “special ones” with the serial numbers of the tamper proof seals printed on it.

Edit:
Reduced size of the picture so sensitive users don’t get offended!
/j

[LoyceV]

Now, when you go back to retrieve the box in the future, you can compare the photos you took before to how it looks now. If anyone has opened it to access your seed phrase, all the grains or whatever you used will have moved around and will look different to the photos.

Being tamper proof only helps you if funds haven't moved between the moment someone tampered with it, and the moment you discover the tampering. So if you hide your transparent container well enough, you probably won't check it very often. And long before you notice someone tampered with it, you'll notice your funds suddenly disappeared.

[o_e_l_e_o]

Being tamper proof only helps you if funds haven't moved between the moment someone tampered with it, and the moment you discover the tampering. So if you hide your transparent container well enough, you probably won't check it very often. And long before you notice someone tampered with it, you'll notice your funds suddenly disappeared.

This is true if you use a single seed phrase and nothing else. If you use a seed phrase and an additional passphrase, or a multi-sig set up, then there is a lot to be gained from having a tamper-evident container. If someone accessed one of my seed phrases, for example, even though they couldn't steal any of my coins I'd definitely want to know that they could now be attempting to brute force one of my passphrases or actively searching for another one of my back up locations so I could take the necessary steps to re-secure my wallets. I'd also want to know that a location I thought was secure had been compromised, since that could have an impact on my other storage locations.

[fillippone]

Being tamper proof only helps you if funds haven't moved between the moment someone tampered with it, and the moment you discover the tampering. So if you hide your transparent container well enough, you probably won't check it very often. And long before you notice someone tampered with it, you'll notice your funds suddenly disappeared.

This is true if you use a single seed phrase and nothing else. If you use a seed phrase and an additional passphrase, or a multi-sig set up, then there is a lot to be gained from having a tamper-evident container. If someone accessed one of my seed phrases, for example, even though they couldn't steal any of my coins I'd definitely want to know that they could now be attempting to brute force one of my passphrases or actively searching for another one of my back up locations so I could take the necessary steps to re-secure my wallets. I'd also want to know that a location I thought was secure had been compromised, since that could have an impact on my other storage locations.

I am always concerned about spreading pass phrases across different locations.
If I am splitting my pass phrase across two locations (12 washers in one container in a hole drilled on a wall, the other on a well in my mountain hut, just to stay on topic), am I making my setup more secure, or less secure?

Of course in a complex dead-man switch multisig setup the tamper proof is more important, but I guess the complexity of the setup is order of magnitude more critical than a simple fund storage.

[o_e_l_e_o]

If I am splitting my pass phrase across two locations (12 washers in one container in a hole drilled on a wall, the other on a well in my mountain hut, just to stay on topic), am I making my setup more secure, or less secure?

You are making it more secure from theft, but less secure from loss. The trick to any back up is finding the correct balance between the two. This will be unique to every person, their circumstances, their personal threat model, the wallets they are using, etc.

I have a couple of wallets which are secured only by a seed phrase. These wallets never contain more than I am willing to lose, such as my mobile daily spending wallet.
I also have several cold storage wallets which contain much more money and are secured by much more than a single seed phrase.

[n0nce]

Prompted by fillippone's latest thread, I got the motivation to finally make an open-source, easily customizable (fully parametric) design of my jig.
The code is found here.
I haven't tested it yet (printed), but from measuring the dimensions and tolerances, it should be almost a 1:1 copy of what I had previously designed in a commercial, closed-source and not free CAD program, with less parametrization.

If there are any questions or issues with the code, or maybe improvement suggestions, let me know.

[NEW!!] OpenSCAD design finalized!
Paste this following code into OpenSCAD (free, open source) and set the parameters to whatever fits your washers and stamps. Then hit F5 and F6 to preview and render the two models. Finally, export the STL file and print it out.

Code:

// n0nce's Steel Washer backup jig
// ---------- configuration ---------- //
washer_dia  = 30;    // set to your washer's diameter (mm)
washer_hole = 10.5; // set to your washer's hole diameter (mm)
washer_h    = 3;     // set to your washer's thickness (mm)
stamp_w     = 8;     // set to your stamp's width (mm)
stamp_d     = 8;     // set to your stamp's depth (mm)

// ---------- code ---------- //
tolerance = 0.25;
// ---------- outer part ---------- //
module roundedcube(xx, yy, height, radius) {
  $fn=60;
  translate([0,0,height/2])
  hull() {
    translate([radius,radius,0])
    cylinder(height,radius,radius,true);

    translate([xx-radius,radius,0])
    cylinder(height,radius,radius,true);

    translate([xx-radius,yy-radius,0])
    cylinder(height,radius,radius,true);

    translate([radius,yy-radius,0])
    cylinder(height,radius,radius,true);
  }
}

module washer() {
  cylinder(h=washer_h, r=washer_dia/2, center=false, $fn=200);
}

module outer() {
  module outer_body() {
    translate([-27, -27, 0])
      roundedcube(54, 54, 20, 3);
  }
  module slot() {
    translate([-5/2,0,washer_h])
      cube([5,23,30]);
  }
  
  difference(){
    outer_body();
    
    // main cylinder to cut out
    translate([0, 0, washer_h])
      cylinder(h=100, r=38/2, center=false, $fn=200);
    
    // washer cut out
    translate([0, 0, -1])
      scale([1, 1, 10])
        washer();
      
    // number slots cut outs
    for (i=[0,2])
      rotate(-14+i*14)
        slot();
    // letter slots cut outs
    for (i=[0:7])
      rotate(82+i*28)
        slot();
  }
}

// ---------- inner part ---------- //
module inner() {
  module inner_body() {
    // main part
    cylinder(h=20-washer_h, r=38/2-0.3, center=false, $fn=200);
    // handle
    cylinder(h=20-washer_h+8, d=9, center=false, $fn=200);
    // sticking out part
    rotate(-14) translate([-4/2,0,0])
      cube([4,22.5,20-washer_h]);
  }
  
  module puncher_hole() {
    sw=stamp_w+tolerance;
    sd=stamp_d+tolerance;
    rotate(-14) translate([-sw/2,
      (washer_dia+washer_hole)/4-sd/2,
      -10])
      cube([sw,sd,50]);
  }
  
  translate([0, 0, washer_h]) {
    difference() {
      inner_body();
      puncher_hole();
    }
  } 
}
outer();
translate([70,0,0])
  inner();

[fillippone]

Prompted by fillippone's latest thread, I got the motivation to finally make an open-source, easily customizable (fully parametric) design of my jig.
The code is found here.
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This is a great news.
Thank you very much n0nce for this.
It will be way more simple to get a jig customised on each own needs.
The stamp customisation will be of utter utility, as it will allow for easier use of “recovered” stamps without buying new ones (Opsec Reasons).

Also, as you mentioned it, I am soon going to translate my thread in English, once I have polished it a little bit.