Bitcoin Forum

Bitcoin => Bitcoin Discussion => Topic started by: PRCman on May 31, 2011, 05:00:36 AM



Title: many people talk about offline spend
Post by: PRCman on May 31, 2011, 05:00:36 AM
They said print the wallet on paper, then spend off line

But the person who spend the money could keep the wallet, and spend it online before the person who receive the money did that.



Title: Re: many people talk about offline spend
Post by: kjj on May 31, 2011, 06:00:00 AM
Yes.  That is the flaw in these schemes.

For offline spending, you need a trusted third party.  Which isn't that big of a deal, really.  The current financial reality is trusted third parties as far as the eye can see.


Title: Re: many people talk about offline spend
Post by: PRCman on May 31, 2011, 06:03:50 AM
Yes.  That is the flaw in these schemes.

For offline spending, you need a trusted third party.  Which isn't that big of a deal, really.  The current financial reality is trusted third parties as far as the eye can see.

Is the wallet a pgp private key? What kind of algorithms  are supported?


Title: Re: many people talk about offline spend
Post by: kjj on May 31, 2011, 06:26:02 AM
Er, wallets and addresses are kinda complicated.

If you understand public key cryptography, you can think of the wallet as holding private keys, and each of your addresses being a public key that matches one of your private keys.  The reality is a bit more involved though, or at least it can be.


Title: Re: many people talk about offline spend
Post by: PRCman on May 31, 2011, 06:58:21 AM
Er, wallets and addresses are kinda complicated.

If you understand public key cryptography, you can think of the wallet as holding private keys, and each of your addresses being a public key that matches one of your private keys.  The reality is a bit more involved though, or at least it can be.

which public key cryptography algorithm does bitcoin supports ex. RSA1024 2048; ECC 190, 239 , does that supported?


Title: Re: many people talk about offline spend
Post by: davout on May 31, 2011, 07:07:39 AM

which public key cryptography algorithm does bitcoin supports ex. RSA1024 2048; ECC 190, 239 , does that supported?

ecdsa


Title: Re: many people talk about offline spend
Post by: db on May 31, 2011, 09:14:13 AM
But the person who spend the money could keep the wallet, and spend it online before the person who receive the money did that.

If you trust them or verify and claim the note before you let them out of your sight you can use this:

http://forum.bitcoin.org/?topic=3716.0

If not and you don't think they can forge one you can use these:

http://bitbills.com/


Title: Re: many people talk about offline spend
Post by: adrian33 on May 31, 2011, 09:21:42 AM
Check out https://github.com/bitcoin-labs/paper-keys


Title: Re: many people talk about offline spend
Post by: wujh on May 31, 2011, 09:41:09 AM
I guess the bitcoin will turn to be some kind of virtue  GOLD, and there will be a lot of virtue CURRENCY based on the bitcoin, like USD based on gold in 1944-1971.

There will be some guy claim that they promise to buy back the CURRENCY they issue with a decided rate, just like US Gov claimed in 1944. And if:

1) Their CURRENCY  is more convenient to use than BTC;
2)They have lots of BTC at first;

Their currency will start to be more popular than BTC, and later, they will:

3) issue more CURRENCY than the BTC hold in their hands at the decided rate.



Title: Re: many people talk about offline spend
Post by: PRCman on May 31, 2011, 10:04:16 AM
I guess the bitcoin will turn to be some kind of virtue  GOLD, and there will be a lot of virtue CURRENCY based on the bitcoin, like USD based on gold in 1944-1971.

There will be some guy claim that they promise to buy back the CURRENCY they issue with a decided rate, just like US Gov claimed in 1944. And if:

1) Their CURRENCY  is more convenient to use than BTC;
2)They have lots of BTC at first;

Their currency will start to be more popular than BTC, and later, they will:

3) issue more CURRENCY than the BTC hold in their hands at the decided rate.



but making fake currency of BTC is not a crime, It's really easy to make fake papers, right?
If someone need online spend, they won't need currency of BTC, they can use BTC directly, for ofline cases there is no way to verify the currency (fake of copied).....