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3261  Economy / Marketplace / Re: Auction for one DRDGold share on: December 19, 2010, 02:58:14 PM
2.24

kiba leads at 2.24 BTC
3262  Bitcoin / Bitcoin Discussion / Re: Using bitcoin and GnuPG to transfer assets on: December 19, 2010, 02:10:27 PM
Like, a 0,01µBTC could be the representation of an asset. Then all you have to do is transfer this particular coin fragment around, and whoever owns it, owns the asset. Ownership could be proven with a simple signature performed by the private key that owns the coin fragment.

This would be ideal, unfortunatly  0.01µBTC would eventually disappear due to mining fees.

Also, I'm not sure those ten nanocoins could not be used by the bitcoin software in order to realise other non-related paiements.

Moreover, what happens exactly when the address holds more than 0.01µBTC ? The owner could send to several addresses, and I don't know how one could know which destination was the "correct" one.

There is no such thing as an identified "coin" in the system.  There are only transactions.  Once a coin is spent, it is just like a water drop in the sea.
3263  Bitcoin / Bitcoin Discussion / Re: Be careful of speading misinformation on: December 19, 2010, 10:20:36 AM

Well, he IS now, isn't he ?
3264  Economy / Marketplace / Re: Auction for one DRDGold share on: December 19, 2010, 09:12:22 AM
2.23

S3052 leads at 2.23 BTC


3265  Bitcoin / Bitcoin Discussion / Re: Using bitcoin and GnuPG to transfer assets on: December 19, 2010, 05:51:22 AM
The BlockChain of custody?

I guess you could call it so, indeed.


PS.  After more thinking, it appears to me this scheme is not sufficient to prevent double spending.

But it's probably not too far from what should be done.

PS#2.  One solution might be to code the PGP fingerprint into the amount.

Here is my GPG fingerprint for instance
3617 0FB4 863D 595A 6E47  0EB6 AB5E F7EF 50B8 0E68

I can easily convert it into 10 integers smaller than 16**4 = 65536.

Code:
for i in 3617 0FB4 863D 595A 6E47  0EB6 AB5E F7EF 50B8 0E68
do echo $((0x$i))
done
Which gives :

13847
4020
34365
22874
28231
3766
43870
63471
20664
3688


I can turn these numbers into amounts bigger than 0.01 BTC.  I have to do that otherwise the message could be corrupted by mining fees.

Code:
n=0
for i in 13847 4020 34365 22874 28231 3766 43870 63471 20664 3688
do echo 0.0$((10**6 + n++*16**4 + i))
done

0.01013847
0.01069556
0.01165437
0.01219482
0.01290375
0.01331446
0.01437086
0.01522223
0.01544952
0.01593512

I use the $n number in order to give a sequencial order to these number.  It is necessary since I doubt there is any sequential order for transactions inside a same block.

Then, all I have to do is to send these amounts to the bitcoin address made out of a signed declaration sayin that I've sold my asset to someone, without saying who exactly.

The advantage is that a receiver of the asset can then check that it has not been sold to someone else before.  In the previous scheme this was not possible if the former receiver doesn't claim the asset.

Such a transaction would cost between 0.1 BTC and 0.1 + 45*16**4 + 10*16**4 = 0.12949120 BTC

That might be a bit too expensive.
3266  Bitcoin / Bitcoin Discussion / Using bitcoin and GnuPG to transfer assets on: December 19, 2010, 05:33:08 AM
In an other thread an asset exchange service was presented :  Loom  (https://loom.cc).

This is quite an interesting service, although it is private, it requires invitation, and is centralised.


I very much think it should be possible to do something similar using bitcoin and GnuPG.

Say I own an asset which is fully described by an ASCII text file "myasset".

In order to give it to Alice, whose GPG fingerprint is "Alice-FPT", I just sign the following document :

Quote from: grondilu
I hereby give the following asset to Alice, whose GPG fingerprint is <here I paste "Alice-FPT"> :

<here I paste "myasset">

In order to prevent double spending, or more precisely to prove that I have not already spent it, I timestamp the signature of this document into the bitcoin block chain.

Then, when Alice wants to give Bob this asset, she signs this :

Quote from: Alice
I hereby give the following asset to Bob, whose GPG fingerprint is <here she pastes "Bob-FPT"> :
Quote from: grondilu
I hereby give the following asset to Alice, whose GPG fingerprint is <here I paste "Alice-FPT"> :

<here I paste "myasset">

And she also timestamp it in order to prevent double spending.


And so on, each owner has to imbricate transfer documents, sign it and timestamp it in order to give it to someone else.
3267  Bitcoin / Development & Technical Discussion / Timestamping a file into bitcoin's block chain on: December 19, 2010, 03:58:47 AM
Here is a script to timestamp or search for a timestamp in the block chain.

Code:
#!/bin/bash
#
# timestamp.sh : Bitcoin timestamping script
#
# This script timestamps or search timestamps into bitcoin's block chain

blockexplorer="http://blockexplorer.com"

# reads data sent on stdin and hash it
sha256=$(openssl dgst -sha256)

# converts hash into a valid bitcoin address
address=$(wget -O - $blockexplorer/q/hashtoaddress/${sha256::40})

shopt -s extglob
case "$@" in
    -s|--search)
        # just search the bitcoin address in the block chain
        w3m -dump "$blockexplorer/address/$address" ;;

    0.+([0-9])|"")
        fee=${1:-0.01}
        if bitcoind getinfo > /dev/null
        then bitcoind sendtoaddress $address $fee
        else echo "Please check bitcoind is running"
        fi ;;
    *)
        echo "
        usage :  $0 [-s]  [amount]
        options :
        -s|--search : only search for a timestamp in bitcoin's block chain
        " ;;
esac


The first data I've timestamped using this code is this code itself (or more precisely my signature of it).

You can check it by running :

$ bash ./timestamp.sh -s < ./timestamp.sh.asc

where timestamp.sh.asc is :

-----BEGIN PGP MESSAGE-----
Version: GnuPG v1.4.10 (GNU/Linux)
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=ecN3
-----END PGP MESSAGE-----


PS.  An other version using rmd160 instead of sha256 (so that we don't have to truncate the hash) :

Code:
#!/bin/bash
#
# timestamp.sh : Bitcoin timestamping script
#
# This script timestamps or search timestamps into bitcoin's block chain

blockexplorer="http://blockexplorer.com"

# reads data sent on stdin, hash it, and converts hash into a valid bitcoin address
address=$(wget -q -O - $blockexplorer/q/hashtoaddress/$(openssl dgst -rmd160))

shopt -s extglob
case "$@" in
    -s|--search)
        # just search the bitcoin address in the block chain
        wget -q -O - "$blockexplorer/address/$address" |
        if grep -q "First seen.*Never used in the network"
        then echo no timestamp found; exit 1
        else echo timestamp found : $blockexplorer/address/$address
        fi ;;

    0.+([0-9])|"")
        # timestamps data by sending a small amount to $address
        fee=${1:-0.01}
        if bitcoind getinfo > /dev/null
        then bitcoind sendtoaddress $address $fee
        else echo "Please check bitcoind is running"
        fi ;;
    *)
        # usage information
        echo "
        usage :  $0 [-s]  [amount]
        options :
        -s|--search : only search for a timestamp in bitcoin's block chain
        " ;;
esac
3268  Other / Off-topic / Re: would you buy a robotic bird for bitcoins ? on: December 19, 2010, 02:00:40 AM
I like it. About how much are they? Are they even for sale yet? I think I would pay $100, maybe more depending on details of durability and battery and such.

I think it will be sold at 75$.  6 to 10 minutes flight time.  The name of the stuff is "Avitron".  Now you know pretty much as much as I do.
3269  Other / Off-topic / Re: Loom currency. What is it? on: December 19, 2010, 01:59:00 AM
I ran into some article about the loom currency. But I do not seem to get what it really is. Can anyone please explain to me, in short, what loom really is and how it compares to bitcoin or other electronic currencies?
Thanks very much.

Here is the article:
http://www.dgcmagazine.com/blog/index.php/2010/12/16/the-new-global-banking-account/

It's not a currency.  It's an anonymous banking system, or more precisely an asset exchange service.

It's very interesting, though.  I could use that for my brokerage project.

PS.  I've ust read the FAQ.  It's pretty cool.  I don't like the centralized aspect, though.

I think it would be a good candidate for an other implementation of bitcoin concepts.  Basically it would be the same service as Loom, but it would work in a decentralised manner, using bitcoin's time server.

This could be neat, but it has to be more thought through.

PS#2.  Hum, it's open source !  This is good, for it means anyone can run his own loom server.  This makes decentralisation not necessary.
3270  Other / Off-topic / Re: would you buy a robotic bird for bitcoins ? on: December 19, 2010, 01:50:01 AM
If you build a programmable kit, I would buy it. It would be useful as a scout bot for the robotic courier network.

I think for the robotic courier network you want a quadricopter.  Seems much more accurate flying, with a much bigger payload.

This one looks pretty neat :

http://www.youtube.com/watch?v=cShsyaV1j6s
3271  Other / Off-topic / would you buy a robotic bird for bitcoins ? on: December 19, 2010, 01:18:16 AM

This toy is so amazing that I consider making it possible to buy it for bitcoins.

Basically I would invest some money to buy a bunch of them, and then I would sell them back against bitcoins.

http://www.youtube.com/watch?v=8oD3yAkT9sI
3272  Economy / Marketplace / Re: auction for 1 EBAY share on: December 19, 2010, 01:09:00 AM
PS.  I'm working on a CGI script that will be GnuPG based.  No password would be required to transfer ownership, you would just sign a text saying you give the share.


that sounds like a good idea. Smiley


Unfortunately the code is quite a bit more difficult to write.  Thus, until then the password system will be used.

I did improve the CGI script though.  Now there is a proper form to enter password and hash.  It's also not limited to eBay any more :  DRDGold will be there too.

http://grondilu.freeshell.org/brokerage.cgi
3273  Economy / Marketplace / Re: Auction for one DRDGold share on: December 19, 2010, 12:37:11 AM
2.22 for one share.  Wink

kiba leads at 2.22 BTC
3274  Economy / Economics / Re: Questions about Gold, brainstorming on: December 18, 2010, 05:14:25 PM

You'd better ask yourself whether you trust the US dollar more than gold.

Gold is gold.  It is what it has always been.

The US dollar is in terrible shape.  If USA don't default soon, they'll have to pay their debt with printed money.  And then the price of gold will go zimbabwean style.
3275  Economy / Marketplace / Re: auction for 1 EBAY share on: December 18, 2010, 07:07:43 AM
FUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUuuuuuuuuuuuuuuuuuuuuu
the block was at 3am and I missed it to a goddamn auction sniper.
Gratz tho lets see if there is a market for this.

You can make a bid to nanotube.  I've tried to make it possible to sell the share after this auction.

He owns the password that identifies the owner of the share.  You can buy him this password.

PS.  I'm working on a CGI script that will be GnuPG based.  No password would be required to transfer ownership, you would just sign a text saying you give the share.
3276  Local / Other languages/locations / Re: Esperanto ! on: December 18, 2010, 05:08:44 AM
u vi verkas ian projekton, kiu rilatas Bitcoin?

Ne, sed mi acxetas bitcoinojn, kay vendas oron kontraux bitcoinoj.

Mi kredas ke tia agado ankaux gravas por la bitcoin projekto.
3277  Bitcoin / Development & Technical Discussion / Re: Exploiting Special Properties of Bitcoin For Uses Other Than Currency on: December 18, 2010, 02:16:02 AM


You don't get it.  It's not steganography at all.  You don't really send any data to the network.  It is the same amount of "data" injected, whether you timestamp a "hello world" or a 1Go tarball !


It seems that I have to make an example to make it really clear.

So, I'm going to time stamp the tarball version of bitcoin, version 0.3.19.

First, I make a GPG signature of it :

$ gpg -s bitcoin-0.3.19.tar.gz

This creates a bitcoin-0.3.19.tar.gz.gpg file, whose sha256 sum is :

$ sha256sum bitcoin-0.3.19.tar.gz.gpg
9e3d69700386772814b0e8c9723d8162c8d88c94479dbd24f18f280b

I turn this hash into a bitcoin address using the convertor in bitcoin block explorer

$ wget -O - -q http://blockexplorer.com/q/hashtoaddress/9e3d69700386772814b0e8c9723d8162c8d88c94479dbd24f18f280b
1BehjJ4trLTY1G148PntLkzb99UYYg5qWEotEAGudWXaW

Finally, I send 0.01 BTC to this address.

$ bitcoind sendtoaddress 1BehjJ4trLTY1G148PntLkzb99UYYg5qWEotEAGudWXaW 0.01

Hum...  bitcoin tells me it's an invalid address.  There must be a bug, but you get the idea, right ?
3278  Local / Other languages/locations / Re: Esperanto ! on: December 18, 2010, 02:01:09 AM
u vi afias je Lernu? Mia nomo je tie samas i tie. Senutila forumo :p Homoj nur babilas pri teda rubo.

Ne, mi ne partoprenas al iu esperanta grupo.  Mi lernis la esperantan nur rete, kaj babilas malofte (ne neniam, sed malofte).
3279  Bitcoin / Bitcoin Discussion / Re: Looking for a knowledgable person to do a radio interview about BitCoin on: December 17, 2010, 07:15:39 PM
Thanks for the info!  I'll contact him.

Please PM Satoshi.  That worths a try.
3280  Local / Discussions générales et utilisation du Bitcoin / Re: French on: December 17, 2010, 05:37:30 PM


Voilà j'ai créé quelques pages, et modifié la page d'acceuil.

J'espère que je suis bien dans l'esprit du truc.
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