Topic: [BOUNTY CLOSED] Open Source (CC) Paper Wallet Kit for safe offline coin storage - page 6. (Read 27627 times)

I love the dark colors! However I think you'll want to be *much* more generous with the whitespace around printable areas, since if the ink misses the mark by just a bit, the ink won't be readable against the background.



Additionally important for QR codes which require a fairly generous whitespace around them to work on many devices.

This week I've been testing high-resolution printing from web browsers, and the variance (even from browser to browser, much less printer-to-printer) is shocking. I'll get printing to work perfect with Safari, and then I switch to Firefox and my prints are 20% bigger and shifted to the left. Oi! Getting an accurate print out of a webpage is going to be a tricky, even with giving folks good calibration tools. Unless someone can get the CSS working a lot better than I have, what I think we should aim for is a design that succeeds to be readable (even if a little offcenter) when the user's prints are:

* up to 1/8" offset vertical and/or horizontal
* and also +/- 10 percent zoom offset

I am actively working on some javascript that will hopefully guide users to calibrate their output for zoom/offset, but in my opinion our final design should anticipate and still succeed when there's significant variance.

Aantonop,

Is it possible to leave an impression on your scratch-off stickers by pressing a hard plastic shape onto them? I'd test with a LEGO since that's similar to the plastic used in 3D printing.

If so my idea is that in your high-end "pro" kit you could also include a little plastic stamper (shortrun 3D printing) that would let you press a subtle bitcoin symbol onto the scratcher. I'm guessing there's no point in trying with ink since the scratcher material is probably some kind of wax/non-inkable surface.



If this ins't at all possible maybe there's some way you can prepare the scratchers before shipping them so they have a bitcoin symbol on them. Maybe there's *something* that will stick to that surface... Maybe if you make a metal stamp and then heat it up?

It's not my intention to make this any more complicated/expensive than necessary. However I think there's a marketing benefit to making something in your kit fairly unique, something that can't be purchased off-the-shelf, something that would be the purchase tipping point for someone who would otherwise just print their own and buy their own scratch off stickers.

Does anyone else want to weigh in on this before I adjust my own design accordingly?

In my current design, the tear-off stub shows the private key twice (once as QR, once as alphanumeric) and the public key twice (once as QR, once as alphanumeric.) To me this seems like the right balance of redundancy and usability. I'm reluctant to redesign the stub in such a way that it's more difficult to quickly check the public balance.

I understand that not everyone will make use of a public QR code on the stub, but since some people will want to be able to quickly verify their balances by using stubs from time to time, and since the private code is already printed twice for redundancy, why not include a public QR code?

Here's my current stub design for reference.

@TheMildChaos

You can do this in illustrator by just drawing one line. Then use the option Effect > Transform > Transform
This lets you just duplicate the line and move/scale/rotate it with every copy. With some tweaking you can get some nice shapes.
Over the years I also found some of these shapes only so that also helps

-----
Some new designs added to while I'm messing around in illustrator watching the charts 
https://drive.google.com/folderview?id=0B1-OuUkg4oEBRC0tVTFIM0ZuSUU&usp=sharing

I think what should be done would be to include checksums or something of the like of which they can verify for themselves that any tampering hasn't been done to the software, regardless of how its delivered. That being said, it's probably cheaper to offer the software as a download.


I never did figure out how to do those curves in Inkscape... Is there any particular guide to drawing those, or is it just experimentation by hand?

I have updated my previous design to comply with the new layout template.

Licensed CC-BY-SA

I still haven't had any time to play around here. Plus all the designs here look so much better than what I could come up with. I had an idea to add though... What about somehow including a watermark or some way for the end user to also print the initial amount loaded on to the paper wallet? Of course people could add more later if they wanted, but at least they would know the minimum amount that should be held in the wallet.

Perhaps something similar to this design?

I was also thinking of something with kind of a trailing full amount like this:

10.12345678

Or doing the ¢BTC, mBTC, µBTC like this:

10.12345678

Maybe with the denomination just above the corresponding numbers?

I imagine most will want to just put a round number on their notes, but who knows? It might be nice to have something like this and I think it helps with readability.

LOVE the new ones, especially the red and purple. Not colors you see on banknotes often, which makes them even better. Great job Timbo.

I am meeting with printing companies today to start conversations. I'll ask about perforation, but here's what I know already:

- These services are called "bindery", which includes cutting, folding, stitching, foil, numbering or other post-print features.

- It costs about $10-$15 per CUT LINE. So if instead of 5, we want 10 lines, it means an extra $50. Not a huge deal, on a $500-$2000 print run.

- There are different types of perforations, depending on the shape and size of the cut. Shapes like "[", "|","L" repeated.

- Micro-perforation is a marketing term for finer cuts.


The biggest thing to find out is the accuracy they can deliver.

The other thing to keep in mind is that a perforation has width. Not much, but some. So the edge will be frayed after tearing even with a micro-perforation die. If you've received a payment cheque in the mail, the type that have a printed statement stub on half the page and a cheque on the other half, you have seen what the industry calls "micro-perforation". It's not as good as an exacto knife.

Very good suggestions proff!

Indeed, it is meant for the newbie, not even the average user. Once you have more than say $500 you want to keep it offline, so that's the target customer/user.

My initial thought was to have the user download the software from openpaperwallet.com, go offline, run it and print. A key part of this project will be the user instructions, which I am writing now and will hope to get help illustrating.

Now, if people think that download-offline-print is too insecure or prone to hijacking, we could add USB keys into the retail product, but that would be up to individual resellers.

Since I hope to be the first reseller of these as kits, let me ask the community here: USB stick or download?

Hi aantonop

I assume your kit is meant for "average" users? If so, isn't the software arguably the most delicate component of this? Since I do not see that it has been explicitly mentioned here, your kit should include something like a bootable DVD or USB stick with secure software pre-installed on it, together with easy-to-follow instructions on how to verify the checksum. Also do not forget that since you are booting into a more-or-less known state it is absolutely essential to introduce enough entropy before generating any random numbers, etc.

Thank for the tips. Faded the top out of the orange lines so if it is not perfect, it should look ok.
The format of the private key is indeed a good idea. Currently using Ubuntu Mono as the fixed width font. The normal Ubuntu font is used in the 'official' bitcoin logo so it should be the perfect fit.
Updated previous post to not spam the topic with pictures.

Must have missed the part about the use of diecut perfs. In that case it might be a good idea to only use horizontal gradients to fix most of the problems.

I like it a lot! A couple ideas:

1) For the alphanumeric full-length private key in the square, if we use a fixed width font and rely on the fact that (as I understand it) WIFs always have 51 characters, then we can always show the key in a tidy pretty square like this:



With the 7 "firstbits" larger for easier checking, and then exactly 4 rows of 11 characters.

2) Regarding bleed/perforation offsets, your design should do great even with a 5-horizontal perforation template -- except for the darker "ripples" in the upper left corner (which would ripple onto the bottom of the bills above it).


I'm coming into this project pretty late so I might be confused on this matter, but I thought the plan was to have diecut perfs so you can just fold and tear -- no exacto knifes needed.

Isn't the back the only place you should be worried about this problem?
If you cutout the bill with a exacto knife you can make a perfect cut if you do it patiently. Then we just need to design a back of the notes with some extra space to cover the bleed. Sounds like the easiest solution.

Oops, I meant to redact this concern! I don't think the bleed issues will impact end users at all. For them we just have to make sure that the final design accommodates at least 1/8" (maybe even 3/16") wiggle room for the placement of the QR codes and keys -- e.g. slightly generous whitespace around the QR code areas.

Here's a virtual test of how my own design would fare if the die cut perfs had a 1/32" vertical variance:



As you can see the left part of my design doesn't do so well, but it's not such a big deal with the right side because of the direction of the gradient.

Whether we have 5 horizontal perfs with no accounting for bleed or 8 horizontal perfs with some added bleed doesn't matter to me -- I can design accordingly -- I just want to confirm what kind of vertical shift on the cuts we should anticipate so that the design can gracefully accommodate any variation.

Used the new template to edit my designs. Will be all adding them to this shared folder. (https://drive.google.com/folderview?id=0B1-OuUkg4oEBRC0tVTFIM0ZuSUU&usp=sharing)
If you see a something wrong or have a good idea to change something, let me know (color scheme can always be changed)


Current Front Designs (More in the link):


(Also without the BTC)


(Also without the BTC)


(Also without the BTC)


(Also without the BTC)


(Other variation in link)

I don't think a professional offset printer will have any problem handling 1/8 inch accuracy on printing or the perforation die-cut. They can achieve 1/64 on the color alignment and at least 1/16 on the cut.

Users may have problems aligning printers as accurately, which is why I was planning to include a few calibration sheets.

Any changes to the template have to be weighed against:

a) The work acorn has already done and will need to re-do
b) The work the other designers have done and will need to re-do
c) The relative value of the change.

If changing the template will make this easier or better, let's do it. I cannot accurately judge how much work it will be, but you give good reasons to consider.

I think rather than making changes, we should first test out some of these issues. You see to like testing the hypotheses (which is great!).

Who is able to run a couple of tests to check if a regular home printer can align a print onto a specific area accurately enough to avoid problems with the "bleed" margins?

One last point: I personally believe there is no need or purpose for the PUBLIC key on the stub, for two reasons. Firstly, you don't need to load a wallet often, It's better to make a new one for security. Secondly, you can recreate the public key from the private key import. So having the private WIF is enough to get the receiving address back. I'd rather have two copies of the private WIF on the stub to double my chances of recovery, than waste one space for a public key I won't use. I have about 100 paper wallets right now and I have never used the public key twice. I have however, had difficulty with one QR code already from a smudge. So my personal experience says two private keys, no public on the stub.

Thanks Acorn! Here's my first round of design. I've taken the liberty to adjust the template a little bit. Most significantly, I wanted to make it possible for the backup/tear-off stub to have QR codes AND alphanumeric codes for both the public and private keys so we don't have to pick. The only font family I use here is Ubuntu (the font used for the traditional bitcoin logo.)



Here's a photo so you can see the actual size including the scratch-off sticker size.



The one concern I have about the template right now is that it will require a great deal of cleverness to make a full-bleed design that accommodates only four horizontal perforations. My design is likely impossible because we'd need to give the printing service approx 1/8th inch wiggle room for inaccurate perforations.

Similarly, it's ambitious to expect that end users will be able to properly calibrate their printers beyond 1/8th inch accuracy.

Should we instead consider having eight horizontal perforations and plan for a 1/8th inch bleed to the design, like this?

Exactly: easy, secure and beautiful paper wallets, pre-printed so you can add the keys.

How much would you pay?

Being able to pre-order the printer paper is a great idea.  What about supplying consumers with pre-printed waterproof-tear proof paper to print their keys on?  Very affordable when buying 5000 sheets or so at a time.