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Author Topic: Bitcoin Checks : R3  (Read 12395 times)
PrintCoins
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June 22, 2012, 03:13:07 PM
 #81

I got my sample today, thanks. Only 5 days to cross the Atlantic via snail mail !
I aggree with enmaku: the "see through" weakness is serious and was clearly identified by Bitbills when they first came out. You want to double the metal hologram sticker with one on the back. I remember the Bitbills guy explaining how he had tested an electronic microscope in its "see through" capacity. Only a dual metal layer can mitigate the risk albeit not entirely.
Right, I thought having a full key would cut down the risk, but not so much. Every check will now have stickers on the back as well. Right now I only have scratch off stickers, but the ones on the back will be replaced by standard non-scratch off holograms in due time.

The full key checks (R1s) will still be available, but by request only, Because nobody wants to type a key that long...

Yep, I went through the same consideration. It is way too easy to see through the paper on the reverse side with a bright light, and so I do holograms on both sides.

Be careful with scratch off stickers. I found that most were removable from the glue layer by applying a little warmth. My first tries were with them, and I was able to successfully take off the scratch off sticker and then re-apply without any issue.

I am currently using these stickers:
http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1313&_nkw=Hologram+Label+Tamper+Evident+25mm+square&_sacat=0

They are not outstanding, but they do a good job of falling to pieces when you try to remove them. I put a small white square of paper over the qr code for the private key to prevent the hologram from remaining on the actual code.

The downside is that as you can see they are easy to purchase and replace by the hacker.

If you want to go hard core, contact casascius, https://bitcointalk.org/index.php?action=profile;u=2676. He has been working with a company on custom holograms that he could be the central provider of that would have a thermal overprint of your company name. This would be very difficult to forge, and so would prevent the problem of a user scraping off the private key cover and then replacing it with a brand new sticker.

Since double stickering means doubling the costs of holograms, you will realize that this gets expensive fast, and in fact making coins and single stickering is cheaper. You might want to consider this route, and again casascius it the man to talk to. It turns out that coins are cheaper to make than holograms, and people like them more, so it is a win-win. If I sold more of my stock, I probably would go down that route as well, but I really don't sell enough to invest in the bulk order of coins. You may also want to look at plastic cards. They can look good, and if you make them thick enough, and dark enough on the reverse, the private key might not be able to be viewed (experimentation needed here).

In any case, good luck! I would love to see more people making physical forms for passing bitcoins along. One of the problems bitcoin has regarding street-corner purchasing is its need for network access and the lengthy amount of time for a transaction to be recorded (I curse satoshi ever time I am trying to give someone bitcoins and we end up twiddling our thumbs for 10 minutes waiting). It also has the nice side effect of transactions being even more anonymous as they happen outside of the blockchain.

I expect that one day when bitcoin becomes a common currency for transaction, there will be many styles of bills, coins, and cards floating about much like the days before the central banks where currency was being printed on a local level.

What exciting times.

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June 22, 2012, 09:47:42 PM
 #82

I got my sample today, thanks. Only 5 days to cross the Atlantic via snail mail !
I aggree with enmaku: the "see through" weakness is serious and was clearly identified by Bitbills when they first came out. You want to double the metal hologram sticker with one on the back. I remember the Bitbills guy explaining how he had tested an electronic microscope in its "see through" capacity. Only a dual metal layer can mitigate the risk albeit not entirely.
Right, I thought having a full key would cut down the risk, but not so much. Every check will now have stickers on the back as well. Right now I only have scratch off stickers, but the ones on the back will be replaced by standard non-scratch off holograms in due time.

The full key checks (R1s) will still be available, but by request only, Because nobody wants to type a key that long...

Yep, I went through the same consideration. It is way too easy to see through the paper on the reverse side with a bright light, and so I do holograms on both sides.

Be careful with scratch off stickers. I found that most were removable from the glue layer by applying a little warmth. My first tries were with them, and I was able to successfully take off the scratch off sticker and then re-apply without any issue.

I am currently using these stickers:
http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1313&_nkw=Hologram+Label+Tamper+Evident+25mm+square&_sacat=0

They are not outstanding, but they do a good job of falling to pieces when you try to remove them. I put a small white square of paper over the qr code for the private key to prevent the hologram from remaining on the actual code.

The downside is that as you can see they are easy to purchase and replace by the hacker.

If you want to go hard core, contact casascius, https://bitcointalk.org/index.php?action=profile;u=2676. He has been working with a company on custom holograms that he could be the central provider of that would have a thermal overprint of your company name. This would be very difficult to forge, and so would prevent the problem of a user scraping off the private key cover and then replacing it with a brand new sticker.

Since double stickering means doubling the costs of holograms, you will realize that this gets expensive fast, and in fact making coins and single stickering is cheaper. You might want to consider this route, and again casascius it the man to talk to. It turns out that coins are cheaper to make than holograms, and people like them more, so it is a win-win. If I sold more of my stock, I probably would go down that route as well, but I really don't sell enough to invest in the bulk order of coins. You may also want to look at plastic cards. They can look good, and if you make them thick enough, and dark enough on the reverse, the private key might not be able to be viewed (experimentation needed here).

In any case, good luck! I would love to see more people making physical forms for passing bitcoins along. One of the problems bitcoin has regarding street-corner purchasing is its need for network access and the lengthy amount of time for a transaction to be recorded (I curse satoshi ever time I am trying to give someone bitcoins and we end up twiddling our thumbs for 10 minutes waiting). It also has the nice side effect of transactions being even more anonymous as they happen outside of the blockchain.

I expect that one day when bitcoin becomes a common currency for transaction, there will be many styles of bills, coins, and cards floating about much like the days before the central banks where currency was being printed on a local level.

What exciting times.

The front will only have 1 scratch off and the back will be a static hologram sticker, eventually. Fortunately my paper isn't as heavy so chances are you would ruin the check before you get the sticker off. I tried this before and just ended up destroying the checks first. Anyone is welcome to continue "hacking" my checks, that's the only way they will get better.
Enmaku should have gotten his new one by now, so waiting to see what he came up with.

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July 05, 2012, 01:41:22 AM
 #83

I've been thinking about multi-signature checks. Maybe have a "pairing keys" on each to verify the owner of the other key maybe? IDK, just a thought.

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TehZomB
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July 05, 2012, 10:05:34 PM
 #84

I just purchased 6, for I really like these things Smiley

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July 06, 2012, 02:21:12 AM
 #85

So Comcast is blocking my email because I dont have Business class service. I can still receive orders, but recent orders will need to be resubmitted. (After 07/04/12)

ES000001 :: Mail to Comcast is rejected and is returned with an error message containing the code ES000001. What does this mean?

You have been blocked from sending to the Comcast network because we have determined that you are sending email from a dynamic/residential IP address within the Comcast domain. Comcast does not allow subscribers to send email from email servers other than smtp.comcast.net.

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July 06, 2012, 02:19:48 PM
 #86

So Comcast is blocking my email because I dont have Business class service. I can still receive orders, but recent orders will need to be resubmitted. (After 07/04/12)

ES000001 :: Mail to Comcast is rejected and is returned with an error message containing the code ES000001. What does this mean?

You have been blocked from sending to the Comcast network because we have determined that you are sending email from a dynamic/residential IP address within the Comcast domain. Comcast does not allow subscribers to send email from email servers other than smtp.comcast.net.
Just set up a quick relay on a VPS somewhere, and make sure it requires authentication. Either that or see if Comcast will relay your mail without mangling it too bad.

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July 06, 2012, 05:44:27 PM
 #87

So Comcast is blocking my email because I dont have Business class service. I can still receive orders, but recent orders will need to be resubmitted. (After 07/04/12)

ES000001 :: Mail to Comcast is rejected and is returned with an error message containing the code ES000001. What does this mean?

You have been blocked from sending to the Comcast network because we have determined that you are sending email from a dynamic/residential IP address within the Comcast domain. Comcast does not allow subscribers to send email from email servers other than smtp.comcast.net.
Just set up a quick relay on a VPS somewhere, and make sure it requires authentication. Either that or see if Comcast will relay your mail without mangling it too bad.
I am just handling the email on my server for the moment until I get my Internets upgraded and can send them out again.

PS. This also means that customers will not receive a CC of their order now since all of my outbound mail is being blocked.

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psjbeisler
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July 07, 2012, 07:58:55 PM
 #88

Comcast wants a $100 installation fee just for some clown to come out and switch out my modem. So instead I am relaying my mail through Gmail, and everything is back to normal now.

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psjbeisler
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July 10, 2012, 03:11:03 AM
 #89

My links have changed in anticipation for an SSL cert. (no more sub-domains)

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Red Emerald
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July 10, 2012, 10:57:43 PM
 #90

Comcast wants a $100 installation fee just for some clown to come out and switch out my modem. So instead I am relaying my mail through Gmail, and everything is back to normal now.
Really? My business class only cost $50 to setup and I complained and got it done for free.

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July 11, 2012, 12:35:13 AM
 #91

Got my dozen today, thanks

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July 13, 2012, 08:18:42 PM
 #92

cheque was in the mail today. looks okay, but I probabyl wouldn't accept one for larger sums. the check itself seems still too easy to fake, the sticker can be bought by everyone, and I don't see the "artificial watermark" on the back. The only thing (besides the second sticker) that could be meant by it are some white letters on a grey background.
final verdict: would accept one for up to 20 fiat from a normal looking stranger.

from here https://bitcointalk.org/index.php?topic=89723.0
So the question is, How do I distinguish/protect against counterfeits...

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July 13, 2012, 08:28:55 PM
 #93

cheque was in the mail today. looks okay, but I probabyl wouldn't accept one for larger sums. the check itself seems still too easy to fake, the sticker can be bought by everyone, and I don't see the "artificial watermark" on the back. The only thing (besides the second sticker) that could be meant by it are some white letters on a grey background.
final verdict: would accept one for up to 20 fiat from a normal looking stranger.

from here https://bitcointalk.org/index.php?topic=89723.0
So the question is, How do I distinguish/protect against counterfeits...
You can't, which is why Bitcoin checks should only be used between trusting parties, just like regular checks.  Stores won't accept a regular check without seeing your driver's license (most of the time), and I imagine it would be a similar requirement for Bitcoin checks, if they were to ever accept them.
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July 14, 2012, 06:08:09 AM
 #94

You can't, which is why Bitcoin checks should only be used between trusting parties, just like regular checks.  Stores won't accept a regular check without seeing your driver's license (most of the time), and I imagine it would be a similar requirement for Bitcoin checks, if they were to ever accept them.
This times one thousand.
Regular checks have the same issues, plus the possibility of bouncing. As a cashier, I have only had a customer attempt (we don't take personal checks) to pay with a personal check one time in five years. It's just too risky, so no business accepts checks at the point of sale.

To improve security, you could use custom-made tamper evident hologram stickers like Casascius uses (although that may require significant investment).

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July 14, 2012, 05:48:08 PM
 #95

cheque was in the mail today. looks okay, but I probabyl wouldn't accept one for larger sums. the check itself seems still too easy to fake, the sticker can be bought by everyone, and I don't see the "artificial watermark" on the back. The only thing (besides the second sticker) that could be meant by it are some white letters on a grey background.
final verdict: would accept one for up to 20 fiat from a normal looking stranger.

from here https://bitcointalk.org/index.php?topic=89723.0
So the question is, How do I distinguish/protect against counterfeits...
You can't, which is why Bitcoin checks should only be used between trusting parties, just like regular checks.  Stores won't accept a regular check without seeing your driver's license (most of the time), and I imagine it would be a similar requirement for Bitcoin checks, if they were to ever accept them.
I agree that you can't make a check impossible to copy, but adding security measures would still increase the trustworthiness of a check and make it useable for larger sums. I understand if you don’t want to invest the money to get custom stickers or something similar, but as I’m skeptical if the niche you seem to be in will be profitable, since I see only two use cases at the moment.
1: people that know and somehow trust each other, but not enough that a handshake is considered enough.
2: strangers that want to exchange goods in person without having to hang around waiting for confirmations. This case has the problem that the check is imho only suitable for smallish sums and is relatively expensive at 0.25 btc. If the problem is the money, get an offer from a custom security sticker maker and crowdsource the costs. You can pay you creditors back with a bundle of checks and 10% rebate off all future offers.

1588Z2nrLstiFwtxunbAnFfUso53HaSCQ7
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August 02, 2012, 02:19:19 AM
 #96

Here is a very nice review! Also, if there are any revision 1 checks still out there, I will replace them.
 http://bitcoinlife.wordpress.com/2012/07/30/cheque-this-out/

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August 17, 2012, 02:10:56 AM
 #97

My checks have now hit Ebay!
http://www.ebay.com/itm/1-bitcoin-physical-check-loaded-with-1-00000001-btc-/170896636880?pt=US_World_Coins&hash=item27ca3bbbd0#ht_500wt_899

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August 20, 2012, 10:42:11 PM
 #98

Sorry I was afk for so long, work has been crazy.

I did get a set of replacement checks and while I don't have any pictures I can say that simply putting an extra holographic sticker on the back absolutely solved the flashlight attack and I haven't found a way to break the new checks yet.

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October 21, 2012, 06:16:40 AM
 #99

I didn't feel the additional scratch off was secure enough nor could I really justify the cost just for an additional sticker, so I changed the checks in an attempt to crush some of that. Currently the private keys are printed in a light  grey color, but instead on a sticker I have a black bar with a watermark of sorts. Also while cutting materials, cutting the price to 75 cents seemed like a good idea too. =)

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October 24, 2012, 02:34:11 AM
 #100

Since I know my new revision will be under heavy pressure I am giving away more checks for people to test and destroy. 20 free checks will go out randomly. How do you get one?
RT
or
+1
to enter.
You have till Friday!


So I got 5 people... I will do a longer offer, I just have some downtime expected

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