Topic: I just made my first Bitcoin ATM withdrawal... 3BTC from my printer. - page 5. (Read 14497 times)
August 08, 2012, 01:26:28 PM
This stuff is begging for an article in The Bitcoin Magazine!
August 08, 2012, 01:26:21 PM
The problem with self printed bills is always going trust. This is where it would be useful the have trusted third party vendors issuing paper currency, with bitcoins to back the value. Hide the private key under a tamper evident hologram just like the coins. You should be able to get these printed for pennies.
There is nothing wrong with having a central issuer of paper money... the problem is when they have an effect on the value of that money. This would not be the case here.
These self printed bills would be great for use where both parties trust the other.
There is nothing wrong with having a central issuer of paper money... the problem is when they have an effect on the value of that money. This would not be the case here.
These self printed bills would be great for use where both parties trust the other.
August 08, 2012, 01:24:44 PM
0.001BTC
1JkoYMWCEE65DyjHBFpC6Gg7YWQvc26FXz
AES 128 PASSPHRASE ENCRYPTED PRIVATE KEY
1JkoYMWCEE65DyjHBFpC6Gg7YWQvc26FXz
AES 128 PASSPHRASE ENCRYPTED PRIVATE KEY
August 08, 2012, 01:21:57 PM
I assume it's the private key that's under your finger. Without any additional security measures, how can one be sure that a paper coin is unspent?
The idea with these is that the receiver of a bill scans the private key, immediately moving the funds to another address. The bill can then be discarded.
So stupid... if you NEED INTERNET ACCESS to verify it, then why is it in paper in the first place?
This is only useful for personal offline backup, never to be used for public transfer.
The recipient needs internet access. I plan to use this method if I for local, in person sale of my bitcoins for cash.
For example: I have a localbitcoin ad to sell 10BTC. Someone responds and we meet wherever he is comfortable with his internet access. I print and fund a 10BTC bill before going out to meet him/her. We exchange cash for paper, and they transfer the coin to there own wallet. Yes, they should have access, but I don't need anything other than my printed coin. I don't have a smart phone so this is ideal for me.
yeah also if you think about gifts. you want to spread the idea of bitcoin within your family and spend gifts of BTC bills to all. so they don't need to check if the bills are funded because they trust in you.
August 08, 2012, 01:11:39 PM
I assume it's the private key that's under your finger. Without any additional security measures, how can one be sure that a paper coin is unspent?
The idea with these is that the receiver of a bill scans the private key, immediately moving the funds to another address. The bill can then be discarded.
exactly this is how the process should work.
August 08, 2012, 01:09:55 PM
I assume it's the private key that's under your finger. Without any additional security measures, how can one be sure that a paper coin is unspent?
The idea with these is that the receiver of a bill scans the private key, immediately moving the funds to another address. The bill can then be discarded.
So stupid... if you NEED INTERNET ACCESS to verify it, then why is it in paper in the first place?
This is only useful for personal offline backup, never to be used for public transfer.
The recipient needs internet access. I plan to use this method if I for local, in person sale of my bitcoins for cash.
For example: I have a localbitcoin ad to sell 10BTC. Someone responds and we meet wherever he is comfortable with his internet access. I print and fund a 10BTC bill before going out to meet him/her. We exchange cash for paper, and they transfer the coin to there own wallet. Yes, they should have access, but I don't need anything other than my printed coin. I don't have a smart phone so this is ideal for me.
August 08, 2012, 01:01:47 PM
I assume it's the private key that's under your finger. Without any additional security measures, how can one be sure that a paper coin is unspent?
The idea with these is that the receiver of a bill scans the private key, immediately moving the funds to another address. The bill can then be discarded.
So stupid... if you NEED INTERNET ACCESS to verify it, then why is it in paper in the first place?
This is only useful for personal offline backup, never to be used for public transfer.
not if you think about a restaurant or a shop. they have always there equipment on. if you want to buy on a flea market for examble the seller of goods have to check if the notes are funded via a mobile and give back the change notes. the big advantage should be that one party are able to take bitcoins with it offline in notes. and sure you can easily hoard it at home as BTC notes.
August 08, 2012, 12:52:42 PM
Actually I thought of a reason why to use AES instead of XOR, even if it were with no IV, and the key were a simple hash of the password (to prevent lengthening of the string). It occurred to me that someone having an encrypted private key along with a decrypted version of that private key would be able to deduce the password hash if XOR was used, which could then be used to decrypt other private keys encrypted with that same password, without knowing the password. AES would probably stop this.
So, back to square one: the actual key standard and encryption method needs to be worked out before Bitaddress.org or something similar can really implement it.
Also an IV and whatnot isn't a real big concern, just use KeyStreching http://en.wikipedia.org/wiki/Key_stretching, specifically PBKDF2 So, back to square one: the actual key standard and encryption method needs to be worked out before Bitaddress.org or something similar can really implement it.
August 08, 2012, 12:52:10 PM
I assume it's the private key that's under your finger. Without any additional security measures, how can one be sure that a paper coin is unspent?
The idea with these is that the receiver of a bill scans the private key, immediately moving the funds to another address. The bill can then be discarded.
So stupid... if you NEED INTERNET ACCESS to verify it, then why is it in paper in the first place?
This is only useful for personal offline backup, never to be used for public transfer.
August 08, 2012, 12:33:37 PM
They are cheques. I would like to have the private key signed with a passphrase though. I have asked the creator of bitaddress.org for the option of a passphrase aes encrypted private key but he does not see the value in this. He is more focused on the brain wallet.
No one has really standardized a way to encode and decode a key with a password.
I proposed one in the Wiki - though not with AES - it would encode a simple XOR of the private key with the hash of the password. I consider AES the wrong tool for the job - AES is great for encrypting a stream of blocks of data - and all the overhead needed to use it properly (key, ciphertext, possibly an IV) would instantly double or triple the length of the key code.
I might implement this in Casascius Bitcoin Address Utility as a reference, and then see who else follows... if nothing else, the same utility could be used to decode password-protected private keys into normal ones.
Actually I thought of a reason why to use AES instead of XOR, even if it were with no IV, and the key were a simple hash of the password (to prevent lengthening of the string). It occurred to me that someone having an encrypted private key along with a decrypted version of that private key would be able to deduce the password hash if XOR was used, which could then be used to decrypt other private keys encrypted with that same password, without knowing the password. AES would probably stop this.
So, back to square one: the actual key standard and encryption method needs to be worked out before Bitaddress.org or something similar can really implement it.
August 08, 2012, 12:04:38 PM
is this the reason to have quarter coins (0.25) available with dollar?
August 08, 2012, 12:02:01 PM
The paper note should have smaller tear off strips of different value so as you use it the note gets smaller over time.
You could call them "bits" of paper....
You could call them "bits" of paper....
Love this. It would tie into a similar solution and terminology developed in the Americas with commodity money:
"A fractional application of the Spanish milled dollar by the colonists was the origin of many terms identified with our current denominations. The English referred to a real as a “bit”, a usage that was subsequently carried over into American commercial outlets and on into the marketplaces until it became a standard term of reference. Since “piece of eight” describes a coin of eight units or pieces, it is only natural that half a dollar would be referred to as four reales or four bits and by the same token, a quartered section of two reales was called two bits. Half of a quartered section was a real or one bit and, divided equally, a bit produced two picayunes valued at six and one-half cents each. When a quartered section was divided unequally on a forty-to-sixty proportion of the quarter section the smaller piece was a short bit valued at ten cents and the larger piece was a long bit valued at fifteen cents."
August 08, 2012, 11:51:26 AM
The paper note should have smaller tear off strips of different value so as you use it the note gets smaller over time.
You could call them "bits" of paper....
You could call them "bits" of paper....
Not a bad idea. Another idea (unrelated) would be to print a change address QR code on the bill.
This sure is a lot easier than building it's electronic equivalent!
The private key is gone on first spend so you don't really want to have it hanging out.
you have to have an addition like vote the receiver via web if he is trustable. if you think of an restaurant or a shop it is a great idea to vote. and there must be a second public key for the changes on the note so that the receiver can give the change back. please have in mind if you give the note (private key) away the whole amount is giving away. you have also to hide the private key in an easy way like putting it in a envelope or purse because there cannot be a complicated mechanism of hiding the private key. everybody should be able to print it out.
August 08, 2012, 11:46:19 AM
Looking lovely - just as with the coins, I think the big bonus here is it makes Bitcoin look Gooood.
I guess they're not too different from Bitcoin cheques, except if the private key is available, these are maybe a bit more transferable/disposable/usable as a paper wallet?
Also like the idea of a keyfob with QR codes on. Might be a good excuse to finally get out that keychain digital photo frame I bought cheap ages ago...
I guess they're not too different from Bitcoin cheques, except if the private key is available, these are maybe a bit more transferable/disposable/usable as a paper wallet?
Also like the idea of a keyfob with QR codes on. Might be a good excuse to finally get out that keychain digital photo frame I bought cheap ages ago...
They are exactly like bitcoin cheques, except you print them yourself, fund them yourself, there's no hologram, and you throw them away once the private key has been shared.
be 100 percent with you. people can print it out for themselves if needed and put it in a purse so the private key is hidden. when they give the note away the receiver has to take care of give back the change also as notes or via network...
August 08, 2012, 11:44:49 AM
The paper note should have smaller tear off strips of different value so as you use it the note gets smaller over time.
You could call them "bits" of paper....
You could call them "bits" of paper....
Not a bad idea. Another idea (unrelated) would be to print a change address QR code on the bill.
This sure is a lot easier than building it's electronic equivalent!
The private key is gone on first spend so you don't really want to have it hanging out.
August 08, 2012, 11:43:14 AM
They are cheques. I would like to have the private key signed with a passphrase though. I have asked the creator of bitaddress.org for the option of a passphrase aes encrypted private key but he does not see the value in this. He is more focused on the brain wallet.
No one has really standardized a way to encode and decode a key with a password.
I proposed one in the Wiki - though not with AES - it would encode a simple XOR of the private key with the hash of the password. I consider AES the wrong tool for the job - AES is great for encrypting a stream of blocks of data - and all the overhead needed to use it properly (key, ciphertext, possibly an IV) would instantly double or triple the length of the key code.
I might implement this in Casascius Bitcoin Address Utility as a reference, and then see who else follows... if nothing else, the same utility could be used to decode password-protected private keys into normal ones.
August 08, 2012, 11:31:11 AM
Looking lovely - just as with the coins, I think the big bonus here is it makes Bitcoin look Gooood.
I guess they're not too different from Bitcoin cheques, except if the private key is available, these are maybe a bit more transferable/disposable/usable as a paper wallet?
Also like the idea of a keyfob with QR codes on. Might be a good excuse to finally get out that keychain digital photo frame I bought cheap ages ago...
I guess they're not too different from Bitcoin cheques, except if the private key is available, these are maybe a bit more transferable/disposable/usable as a paper wallet?
Also like the idea of a keyfob with QR codes on. Might be a good excuse to finally get out that keychain digital photo frame I bought cheap ages ago...
They are exactly like bitcoin cheques, except you print them yourself, fund them yourself, there's no hologram, and you throw them away once the private key has been shared.
They are cheques. I would like to have the private key signed with a passphrase though. I have asked the creator of bitaddress.org for the option of a passphrase aes encrypted private key but he does not see the value in this. He is more focused on the brain wallet.
August 08, 2012, 11:19:13 AM
Looking lovely - just as with the coins, I think the big bonus here is it makes Bitcoin look Gooood.
I guess they're not too different from Bitcoin cheques, except if the private key is available, these are maybe a bit more transferable/disposable/usable as a paper wallet?
Also like the idea of a keyfob with QR codes on. Might be a good excuse to finally get out that keychain digital photo frame I bought cheap ages ago...
I guess they're not too different from Bitcoin cheques, except if the private key is available, these are maybe a bit more transferable/disposable/usable as a paper wallet?
Also like the idea of a keyfob with QR codes on. Might be a good excuse to finally get out that keychain digital photo frame I bought cheap ages ago...
They are exactly like bitcoin cheques, except you print them yourself, fund them yourself, there's no hologram, and you throw them away once the private key has been shared.
August 08, 2012, 11:16:30 AM
Looking lovely - just as with the coins, I think the big bonus here is it makes Bitcoin look Gooood.
I guess they're not too different from Bitcoin cheques, except if the private key is available, these are maybe a bit more transferable/disposable/usable as a paper wallet?
Also like the idea of a keyfob with QR codes on. Might be a good excuse to finally get out that keychain digital photo frame I bought cheap ages ago...
I guess they're not too different from Bitcoin cheques, except if the private key is available, these are maybe a bit more transferable/disposable/usable as a paper wallet?
Also like the idea of a keyfob with QR codes on. Might be a good excuse to finally get out that keychain digital photo frame I bought cheap ages ago...
August 08, 2012, 10:30:13 AM
Do the QR codes work with any mobile digital wallets? Android has one.
http://www.wired.com/gadgetlab/2011/07/bitcoin-android-app/
http://www.wired.com/gadgetlab/2011/07/bitcoin-android-app/
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