Bitcoin Forum
June 12, 2024, 09:57:06 PM *
News: Latest Bitcoin Core release: 27.0 [Torrent]
 
  Home Help Search Login Register More  
  Show Posts
Pages: [1]
1  Local / Suche / Suche Händler für PC-Komponenten (der BTC akzeptiert) on: June 23, 2015, 03:32:51 PM
Ich poste es hier bei "suche" da anscheinend immer noch kein Unterforum für dieses wichtige Thema (Händler die Bitcoin akzeptieren) existiert und auch die entsprechende Wiki-Seite anscheinend nicht gepflegt wird.

Also nach längerer Bitcoin-Community-Abstinenz bin ich bin nun aktuell auf der Suche nach einer Graphikkarte (nicht zum Minen sondern zur Verwendung für den eigentlichen Zweck einer solchen). Natürlich könnte ich ohne Probleme den nächstbesten "normalen" Händler ansteuern und mir eine bestellen und per PP zahlen aber ich hab noch ein paar BTC übrig und nachdem nun soviel Zeit ins Land gegangen ist sollte doch wohl mittlerweile irgendwo in Europa der eine oder andere Händler existieren der auch BTC akzeptiert.

Wenn es irgendwo eine aktuelle Liste von Händlern gibt dann bitte Link posten, ich wüsste nichtmal mit welchen Suchbegriffen ich Tante Google füttern müsste um solche Händler zu finden.

Der Händler muss nicht in D sitzen, kann gerne irgendwo in Europa sein (aber nicht außerhalb, wegen Zoll).

btw. wo wir gerade von Graphikkarten sprechen, wo enden eigentlich die ganzen Karten der Leute die sich mal mit GPU-Mining beschäftigt haben, daran aber den Spaß verloren haben, gibts da evtl einen Ort wo einem die über den Weg laufen?

Ich suche was in der Größenordnung wie AMD R7 260x, also kein extrem teures High-End Spielzeug sondern eher solide Mittelklasse.
2  Local / Biete / Biete HAMEG 312-8 Zweistrahl-Oszilloskop, 20MHz, defekt on: September 24, 2014, 06:12:23 PM
HAMEG 312-8
Zweistrahl-Oszilloskop, 20MHz

**DEFEKT**

Als Ersatzteilspender. Das Gehäuse sieht überraschend sauber aus und praktisch keine Kratzer, keine abgewetzten Frontplattenbeschriftungen, fast so als wäre es kaum benutzt worden, allerdings ist es leider defekt.

Als es bei mir ankam stand der Netzspannungs-Wahlschalter auf 125V (!), nach den Einschalten (mit korrekter Einstellung 240V) gibt es Überschläge auf der Z-Platine, die Hochspannung scheint also noch zu funktionieren. Beim Umdrehen fielen mir Glasscherben entgegen, die Röhre ist defekt!

Ich verkaufe es für 0.08 BTC an Selbstabholer in Hannover (nähe Garbsen).

3  Other / MultiBit / middle-click paste (under xorg) of the send amount will not update the amount on: June 26, 2014, 06:21:10 PM


Steps to reproduce:

* switch to the send tab, the previously sent amount is in the amount field (in the above example 5 BTC)
* click new, enter a new bitcoin address to send to, optionally a new label
* click into the amount field, clear it entirely using delete or backspace
* middle-click to paste the contents of PRIMARY into the amount (in the above example 0.0038625 BTC)
* the fiat currency text field is not updated (stays empty)
* click send
* see screenshot

________
PS:

please PLEASE while you are at it before you close your IDE again after fixing this bug: after sending please, please, please clear the amount, the address, the label immediately automatically, so when I switch from the transactions to the send tab I find it completely *empty* and can immediately begin entering address and amount. I cannot count the numbers of times anymore where I messed up my labels because quickly pasting an address into the send tab for quickly sending some coins. This is the single one most annoying user interface glitch of all, noobs will regularly fail to use it properly.

Alternatively you can also implement it so that if I replace the address in the send tab then it will also clear the label and the amount and have the same effect as pressing "new", maybe this ls less invasive but serves the same problem.
4  Bitcoin / BitcoinJ / pure Java code (Xtend actually) to read keys from wallet.dat on: May 21, 2014, 09:32:02 PM
...decrypt it and and create c.g.bitcoin.core.ECKey instances from the keys.

If anybody of you ever felt the urge to parse a Berkeley database (wallet.dat) without linking against libdb, and use the keys in your bitcoinj based application: here is some inspiration: https://github.com/prof7bit/wallet-key-tool/blob/master/src/main/java/prof7bit/bitcoin/wallettool/fileformats/WalletDatHandler.xtend

 Grin
5  Other / MultiBit / Blockchain.info (*.aes.json) -> Multibit (*.wallet) or (*.key) on: May 15, 2014, 08:53:46 PM
I have written entirely new code from scratch to read the wallet.aes.json files from BCI. Unlike the old code that was in MultiBit and has now been removed (because it was broken) this one will handle compressed keys correctly! It is contained in my wallet-key-tool.

https://github.com/prof7bit/wallet-key-tool

to import *.aes.json into MultiBit:

in wallet-key-tool:

* click "load..."
* in the file dialog select "Blockchain.info" from the filter drop down list
* find your wallet.aes.json file and click "open"
* enter primary (and possibly secondary) password to decrypt
* (optional) check balances by fetching them from BCI and make sure you have the right keys
* (optional, recommended) check and update the creation dates
* (optional) add/remove keys or import even more wallet files
* click "save as..."
* in the file dialog select "Multibit wallet (*.wallet)" or "Multibit backup (*.key)"
* choose a folder and file name to save the file, click "save"
* choose a password to encrypt

in Multibit

* open the wallet if you saved as .wallet
* or import into existing wallet if you saved as .key

Multibit will replay the block chain when first opened in MultiBit. To prevent syncing all the way back from 2009 you should make sure you updated the creation dates of all keys in wallet-key-tool before exporting to Multibit.

Make a backup of your MultiBit wallets before you begin. Although my tool will refuse to overwrite existing files (it will only generate new files) you could import the generated .key files into your existing Multibit and once they are imported they cannot easily be removed again (of course you could then import the .wallet in my tool, remove keys and save it as a new .wallet and it will work without problems but nevertheless I recommend making a backup of all your original files before you begin experimenting with this)

Screen shots: http://imgur.com/a/oUTto

Disclaimer: This software is not part of Multibit, its a separate tool, we are not affiliated, its using the official Bitcoinj and Multibit code to read/write the wallet formats but its a different tool and any bad things that might happen are solely your own fault (because you did not follow the above warning about backups of your original files)
6  Local / Suche / [erledigt] Suche 2 gebrauchte PC (komplett) (evtl. auch günstige Neuware) on: January 05, 2014, 07:54:34 PM
Anwendungsbereich: Office, Web, Verschiedenes, kein Hardcore-Gamer. Entweder nicht allzulang gebracht oder ausgelaufene Vorführmodelle, Windows 7 (keinesfalls 8!), 64 bit, ausreichend RAM (lieber mehr als weniger, ich will nie wieder Gesichtslähmung bekommen wenn ich Eclipse starte während der Browser noch offen ist, nie wieder!), keine high-end Graphik (wird nicht zum Zocken verwendet und auch nicht zum Minen), jedoch würde ich auf einem der beiden parallel auch Linux installieren wollen, ein kleines bisschen open-GL sollte also schon gehen, also keine on-board-Schrottgraphik von SiS oder ähnlich inkompatibles Zeugs.

Ich bräuchte genau 2 Stück, komplett mit brauchbarer Tastatur, Maus und brauchbarem Bildschirm.

Ich lass vielleicht auch mit mir reden wenn ihr nur einzelne Komponenten da habt, also z.B. zwei ordentliche Mainboards mit CPU+Kühler+RAM aus der Windows 7 Ära (und natürlich mit Windows und Treibern) und jemand anderes die restlichen Teile anbietet so daß ich für nen vernünftigen Preis alles zusammenbekomme was ich brauche aber je kompletter desto besser.

Ich könnte die Geräte in Hannover abholen und Bezahlung würde in Bitcoin erfolgen, aber bevor wir vom Bezahlen und Abholen sprechen möcht ich erstmal lesen was ihr so anzubieten habt. Also her mit den Angeboten damit ich mal sehen kann was meine bitcoins heutzutage so wert sind :-)
7  Bitcoin / Electrum / hashing the seed or hashing the hex-string representation of the seed? on: November 09, 2013, 08:20:25 PM
I'm playing around with electrum 1.9.2

It seems that with seed_version=4 if I do

./electrum --offline --wallet=testwallet restore

and enter "ffff" as seed I will get different results than when entering "FFFF". Looking into the code it seems you are indeed hashing the string representation of that hex number:

account.py, class OldAccount
Code:
   def stretch_key(self,seed):
        oldseed = seed
        for i in range(100000):
            seed = hashlib.sha256(seed + oldseed).digest()
        return string_to_number( seed )
and seed is the hex string representation of the seed. I guess that cannot be chaned anymore without making it incompatible.

Now I looked into the new seed_version = 6 stuff with bip-32, I simply patched wallet.py to set self.seed_version=6 to trigger the new code paths and it still is hashing the string representation:

Code:
   def create_master_keys(self, account_type):
        master_k, master_c, master_K, master_cK = bip32_init(self.get_seed(None))
        [...]

    def get_seed(self, password):
        s = pw_decode(self.seed, password)
        if self.seed_version == 4:
            seed = s
        else:
            seed = mnemonic_hash(s)
        #todo:  #self.sequences[0].check_seed(seed)
        return seed

shouldn't this line be

Code:
       else:
            seed = mnemonic_hash(s.decode('hex'))

I changed it to see what happens and also inserted a few prints here and there to see whether its handling binary data or hex-strings and now it seems to work correctly and will produce the same keys for "ffff" and "FFFF".

with above patch and bip32 enabled I get the following addresses from "FFFF" or "ffff"

1JFGdf7FsmNZEsPWUZeCRqcKUZF4iTLKjk
1BbHtbsX4ajyb6vVrTtatrUiGMGUtZaVMX
1HjFdepBf9qg8BKmLtRf9iYBWa1YFRV2hp
1QHErKePKQurWELiJD2pTwaxEwZZPjMogX
16p6r7vyj8B2t6SbugYgoHQJhX8XkBpX4G
1Bhqh25w998MsxJjnEfAxPLvrjCi4zB7xF
13k5Zivs8Zw9QUfYcVbG3w8rHV3KjTR2Xk
19hVwRqH57FtFYKyZf2SsEsoEeFJ3aj2NH

and the argument to bip32_seed() is now 974e4be2c4f570e64ec86819bf8d14a66584481993b5e82d6400c78288025c5c40cd6e1d1218107 ee778174af562ceae7e4c31ff206f7cfe5708fb65ba4853f5


Please tell me that this is indeed a bug and not intentional
8  Local / Deutsch (German) / Umsatzsteuer on: August 19, 2013, 02:27:02 PM
Hallo, kann mir mal jemand kurz (oder lang?) erklären wie das mit der Umsatzsteuer auf Bitcoins funktionieren soll?

Nehmen wir mal an (der Einfachkeit halber) der Kurs wäre gerade bei 100€ und ich wäre ein gewerblicher Bitcoin-Händler und normalerweise würde ich Bitcoins für 102 verkaufen und für 98 ankaufen. Was ist jetzt wenn die Umsatzsteuer dazu kommt und ich würde normalerweise 1 BTC für 102€ verkaufen, muss ich jetzt stattdessen noch 19% draufschlagen? Und wenn ich für 98 ankaufe, muss ich 19% einbehalten? Das kann doch nicht sein, der Handel würde doch zum Erliegen kommen, kann mal bitte jemand eine Beispielrechnung aufmachen wie das vonstatten gehen soll wenn das überhaupt möglich it? Auch im Hinblick auf Händler die Waren für Bitcoins verkaufen, wie sollen die den Preis der Ware in BTC berechnen? Ich blick grad überhaupt nicht mehr durch wie Umsatzsteuer auf **Geld** überhaupt funktionieren soll.
9  Bitcoin / Bitcoin Discussion / QR-Codes for addresses on websites on: May 26, 2013, 10:25:54 PM
This topic does not fit anywhere else, so I am posting it here.

Today I was confronted with the following problem: I was sitting in front of my desktop PC, using my web browsr and came upon an address where I suddenly felt the need to send money to instantly (it was a betting site). My everyday money is on my Android phone, I wanted to make the payment from the Android wallet.

Unfortunately the address on that website did not display any QR-Code and so I had an idea: There must be a greasemonkey script to display QR-codes for any address on any website. I couldn't find anything usable on userscripts.org so I decided to make one myself. Here it is: http://userscripts.org/scripts/show/168629

When its installed and you hover above any BTC address then it will pop up a QR-code for that address. I have tested it on Qupzilla (this is a webkit browser so it might also run on Chrome) and I also tested it on Firefox. Please try it and give me some feedback.
10  Economy / Trading Discussion / goxtool bot: stop loss (optionally trailing stop) on: April 22, 2013, 06:38:38 PM
Many have asked for it, here is my first attempt:
https://gist.github.com/prof7bit/5437131
(please test and report bugs, will update the code if needed)

STOP_PRICE is the price at which you want to sell (value is in USD or EUR or any other Fiat), if the value is negative it will enable trailing stop mode and it is interpreted as a price difference (enter for example -12.5 here if you want to trail the stop $12.50 below the highest price (highest since strategy (re)loaded).

STOP_VOLUME is the value in BTC to sell when the stop is triggered. It will trigger only once, after it has been triggered you need to reload strategy ("l" key)

as usual: newest version of goxtool is needed, save as _stoploss.py and start gotool with

./goxtool --strategy=_stoploss.py --protocol=websocket --use-http

Messages will be visible in goxtool.log, use tail and grep to follow them in realtime.

Also the usual disclaimer applies: read and understand the code before running it (otherwise don't run it) and since you have read and understood what it will do in every detail before you decided to run it I cannot be held responsible for anything that results from your decisions.

11  Economy / Trading Discussion / goxtool bot: portfolio rebalancing on: April 20, 2013, 05:38:00 PM
I'm making separate threads for individual goxtool bots to keep the goxtool thread for goxtool related stuff only. I choose this forum because the goxtool thread was moved into this forum too. (Similar software sometimes gets moved into different forums, I believe there is a forum missing for all kinds of software that is bitcoin related but *not* a bitcoin client/wallet itself)

And here is the balancer bot:
_balancer.py: https://gist.github.com/prof7bit/5395900

This bot will maintain a constant asset allocation ratio Bitcoin/Fiat = 50/50
http://en.wikipedia.org/wiki/Rebalancing_investments#Rebalancing_bonus
It will do so by placing limit orders above and below current price that will restore the 50/50 ratio once price moves there and fills the order. As soon as one order is filled it will cancel the other and then calculate and place 2 new orders above and below that new price. The price distance of the orders is 7%, that can be changed in the variable DISTANCE you should not make it smaller than 2%).

This strategy will produce a small profit in the long run (a few percent per week if there are huge price swings or nothing at all when its going sideways for many days), it seems a promising strategy for BTC/USD because of its insanely high volatility but it will also make your account balance go up and down directly in tandem with BTC price, so prepared to see huge swings in your account. You should write down BTC-price, USD and BTC balance in your account once a week and plot these curves after a few months or years to see the effect. This is not a get rich quick bot, this needs patience!

Installation and usage:

  • prerequisites: you are familiar with the usage of goxtool.py
  • (most important) update goxtool to the latest version (git pull)
  • save the file from the above link as _balancer.py in the same directory as goxtool
  • ./goxtool.py --strategy=_balancer.py --protocol=websocket --use-http
  • (optional) open a separate terminal and tail -f goxtool.log | grep Strategy to follow the debug output of the strategy module
  • cancel all orders and bring your account into 50/50 balance, do so by pressing the b key
  • start the bot by pressing the p key

Disclaimer: If the above sounds chinese to you or you cannot read the code or don't understand what it does or you are not a Linux user (needed for goxtool) then algo trading is not for you. You should have the skills to implement this yourself from scratch given the description of the strategy or be able to read, understand and debug every aspect of the existing code or it will only end with a huge disappointment or maybe even a desaster.

As you can see in the code the the bot has some some hotkeys bound to certain actions to control its operations:

i show info about current status (how much out of balance)
c cancel all open rebalancing orders and suspend trading
b rebalance immediately with market order at current price
p place a pair of fresh rebalancing orders and start/resume trading
u manually force update of own order list and other stuff (should only be needed when socketio connection behaves strange or is down or other related problems, not used for normal operations)

like all other goxtool strategies it can be reloaded at runtime without restarting goxtool (for example after editing DISTANCE) by pressing the l key (lowercase L).

As you also can see from the code it is triggering its trades when it has detected the number of orders being exactly 1, this does not happen in the trade message, the user_order message is the last API message that is sent after a series of messages updating the wallet and the trade message (and this signal is also triggered after reconnect), so this is the best place to trigger new orders, knowing that the wallet is updated already (we need the new account balance for the calculations).

When the bot ever comes out of sync, I have seen this happening when price is jumping around too fast and you choose DISTANCE too small and mtgox is under ddos at the same time and the connection becomes really unreliable then you need to cancel all orders (press c to cancel and halt trading, also check with F6 that really all orders have been canceled, maybe use u to manually update if socketio is down and if its screwed up totally then restart goxtool. This should not happen very often) and then check if you need to rebalance (press i and see the log) and if needed manually rebalance (press b) and then resume automatic rebalancing (press p).
12  Other / Meta / The forum software does not parse old school smileys :-( on: April 19, 2013, 12:04:46 PM
these are the ones that are commonly used by people older than 40 years

:-)
:-(
;-)

it will parse only the new style smileys:

Smiley
Sad
Wink
13  Economy / Speculation / There was no crash on: April 13, 2013, 11:16:17 AM
A few weeks ago:

she: "what is this?"
me: "Bitcoins. They went to $40 per BTC"
she: "how many do you have?"
me: "Not many. Only around $number"
she: [calculates...] "Oh! How about a new car? And a new $this and a new $that, and..."

Today

she: "how are our¹ bitcoins doing?"
me: "they crashed"
she: "Oh..."
me: "They are now at $115 per BTC"

________
¹ Sic!
14  Economy / Securities / How do these stock exchanges work? on: March 17, 2013, 09:32:08 PM
This might be a dumb question but I wonder how does this work:

Say for example there are two different exchanges (for example bitfunder and btct, these two I have found accidentally through some quick google search, lets call them A and B) and a company XYZ has issued a number of nnn shares in total and they are traded on both exchanges.

* how do (some of) these shares initially end up at A or B where the investors can buy them

* If I buy 100*XYZ at A, can I move them to B and sell them at B (or can I completely take them home with me and/or sell them elsewhere/offline or here in the forum (I have seen at least one thread here where they traded ASICMINER shares here in the forum and at the same time I also see ASICMINER shares being traded at aforementioned exchanges A and B)?

* who keeps track of who owns how many shares (globally because there (should) exist only nnn of them), is there some global registry, what if some exchange decides to sell more shares than they have? Is there some established protocol that solves the double-spending problem for these shares that all these exchanges implement? How does this work?

* Is there a list of such exchanges?

15  Economy / Speculation / Fair value is at 53.31$ ;-) on: March 09, 2013, 05:02:53 PM
see here: (click for larger image)


5.487 Million USD total on the bid side vs 102931 BTC on the ask side,
this is a ratio of 53.31 USD per BTC :-)
16  Economy / Trading Discussion / ncurses based MtGox live monitor and trading-bot-framework on: March 02, 2013, 08:55:12 PM
...written in python. Curses based UI, live orderbook, ascii-art chart of latest 24h, trading functions can be defined in separate module "strategy.py" which receives all events from the gox client and all keystrokes from the terminal. Strategy module can be edited and reloaded at runtime which is great for experimenting with bots. Works also without MtGox API-key to view only without trading.


(still experimantal, license: GPL3)
http://prof7bit.github.com/goxtool/
https://github.com/prof7bit/goxtool

screenshot


Usage:

  • it needs python 2.7 (and maybe a few additional packages but nothing that would not be found in the standard ubuntu repositories). It will NOT work on Windows because there exists no ncurses (maybe it works with cygwin, not tested)
  • Download and unzip (or better git clone the repo from github).
  • ./goxtool.py

This should give you the orderbook on the left side and an M15 candlestick chart of the lat 24 hours (if your terminal is wide enough) on the right side and a log window at the bottom.

To use the trading features do the following:

./goxtool.py --add-secret

This will ask you for your MtGox API key and secret, you get them at the mtgox website, copy and paste key and secret, supply a passphrase which will be used to encrypt the secret. Then it will write the encrypted secret to goxtool.ini and exit. The next time you start ./goxtool.py it will ask for the passphrase to access the API secret and then all trading functions will be enabled, you will see your own orders in the orderbook and in the chart and your account balance at the top of the terminal.

To use it with other currencies, just edit the ini file. If it is one of these days when the socket.io just wont want to connect, edit the ini file and change use_plain_old_websockets to True. If you don't need history or full orderbook you can turn it off in the ini too.

press q to quit the program.
press F4 to buy
press F5 to sell
press F6 to view orders / cancel orders
press l (lowercase L) to reload the strategy module at runtime.
any other key will call the slot_keypress() in the Strategy class in strategy.py, see the examples. Here you can call methods like gox.buy() or .sell() or .cancel()  or peek around in the order book to decide what fancy stuff to do.

(this forum posting and the instructions might eventually come out of sync with the current version, see here for the official manual: http://prof7bit.github.com/goxtool/)

There are also methods that will be fired on signals from the gox object, you can use them to build fully automated trading bots (there exist even more signals to connect to, for example orderbook.signal_changed or gox.signal_wallet, etc. Look into the source of goxtool to find them all). You can also instantiate more Gox() objects from within your strategy for different currencies (you will also need separate GoxConfig() objects for each of them that use separate config files) to trade multiple currencies at once (useful for arbitrage strategies).

And finally you can rip out parts of this for your own programs, you can just import goxapi and use the Gox() class on its own in your own program, connect your slots to its signals and make your own UI for it (or no UI at all).
17  Bitcoin / Development & Technical Discussion / the goxsh script is zero-padding the secret and then encrypting in ECB mode on: February 27, 2013, 08:27:34 PM
hello!

I am not a crypto-guru, so I might be wrong but this seems highly suspicious to me:


      password = password[0:32]
      aes = AES.new(password, AES.MODE_ECB)
      secret = str.zfill(secret, 128)
      secret = aes.encrypt(secret)


It turns out that before zero padding the length of secret is 88 bytes and after it is 128 bytes, so there is more than one complete block (key length = 32 bytes) of known plaintext and because of ECB mode all other 32 byte blocks will be encoded with the very same key! Isn't this danegrous? Shouldn't it be padded with random bytes instead and also the ECB mode be completely avoided?
18  Bitcoin / Electrum / electrum server/protocol vs. stratum server/protocol - please clarify confusion on: September 20, 2012, 11:43:18 AM
There is this: https://bitcointalk.org/index.php?topic=55842.0
that somehow suggests that "electrum" and "stratum" are actually the same thing or "stratum" is the new name for "electrum"

Then there quite a lot of postings or answers along the lines of this (for example): https://bitcointalk.org/index.php?topic=91939.msg1013281#msg1013281
that come up when googling for "electrum protocol" or "electrum stratum" that claim that electrum is actually using the stratum protocol or that there is no need to reverse engineer the electrum protocol because there is the stratum protocol documentation.

There is this: http://stratum.bitcoin.cz/
not very informative and mentioning exactly one running stratum server (and nothing about electrum)

    california.stratum.bitcoin.cz (Ports 3333 TCP, 8000 HTTP, 8001 HTTPS, 8002 Websocket, 8003 Websocket SSL, California US, hosted by BitVPS.com).

and there is this: http://electrum-desktop.com/
mentioning nothing about the used protocol, the servers and especially no reference to stratum at all. The client when started present a short list of servers:

ecdsa.org
uncle-enzo.info
electrum.bytesized-hosting.com
electrum.novit.ro

and when trying to use the california.stratum.bitcoin.cz in electrum I get only error messages like [-3, u"Method 'subscribe' not found for service 'server.peers'", None] and a few more which suggest that the electrum and the stratum protocols are not the same thing.

Now here come the questions:
* how are stratum and electrum related?
* if not related then does there exist an electrum-like client for stratum?
* how many electrum servers are there?
* how many stratum servers are there?
* which *existing* protocol should be chosen when implementing an electrum-like client?
* if the answer to the last question is electrum then where is the protocol documentation (if such a thing exists at all)?

Maybe it would also be nice if both (the stratum and the electrum) websites clearly state that they are *not* related (or if they are related somehow then maybe explain in which way they are related or if there exist other "stratums" or "electrums" with the same names that are not related, etc).

19  Bitcoin / Wallet software / Free Pascal (Object Pascal) Bitcoin Client on: July 21, 2011, 10:42:57 PM
I want to anounce that I have started working on an implementation of the full Bitcoin p2p potocol (and Wallet functionality) in Object Pascal.

The sources are available under LGPL with static linking exception (same as the Lazarus components), and I am trying to make it as portable as possible for a wide range of platforms and CPUs (even big endian CPUs) while the main focus is on fast bootstrapping (initial block download), extremely fast startup times, low Bandwidth usage, low HDD usage, low RAM usage.

It will consist of the core (non UI) units for the p2p, wallet, transaction functionality that can be linked into your own applications and later (not yet started) also a rich GUI for Windows, Unix, Linux, Mac-OSX that will be made with Lazarus/LCL for superior end user experience.

the project home page is here: http://code.google.com/p/fpbitcoin/

Currently there are no downloads yet but you can check out the (half finished and slowly growing) source from svn already and study it, experiment with it, etc.

I try to document it as good as possible to make it usable for documentation purposes also, so it might help others to get started with their own implementations too. If you see something strange in the code that needs explanation (or needs improvement or is an outright error) then please tell me and I will try to document it, improve it or fix it.

20  Bitcoin / Development & Technical Discussion / Proposal: UI for "create wallet" and "open wallet" (and also crossed cheques) on: June 16, 2011, 10:24:47 AM
Hi,

I couldn't find anything like this already but it seems logical to me and very useful to provide the following two functions in the client, easily accessible with a few mouse clicks:


1) "create wallet"

A very simple (intuitive to use) dialog pops up asking for a file name and an amount of bitcoins. If the user clicks OK then a new empty wallet is created and saved to the specified location. Then after successful creation of the wallet (file close and flush to disk) a transaction is initiated to transfer this amount of bitcoins to this new wallet.


2) "mount wallet" (or "open external wallet" or whatever is more intuitive)

A file selection dialog pops up, the user selects a wallet file, (or drag&drop a wallet file onto the running client or simply double-click a wallet file) the file is opened and a simple separate window opens (representing this wallet) displaying the following (and not much more to avoid confusion):

_________________________
External Wallet file
_________________________
Balance: xxx.xx BTC
Import this amount of BitCoins from this wallet: [__xxx.xx__] [Import]
[close wallet]
_________________________

And maybe a third button to easily send the remaining funds back home to where they initially originated when this wallet was created (or optionally to any other address).

The use case I have in mind is the following: I am a private person and want to sell an item, for example my old bicycle. Normally (in the old days before eBay) I would have put a small advertisement into one of these newspapers and announce that I have a used bike for sale along with a phone number (or email) where they can call me and I would tell them to come over to my house to inspect the bike and bring xx€ cash with them and if they like it and we arrive at a price then they can immediately take it with them.

With BitCoin how would I currently tell them to bring xx BTC with them? The buyer would have to trust one of these online services to create a temporary wallet, fill it with just enough to buy the item and after the transaction he would have to delete the account again and create another one for the next such occasion (because I am evil and would have a keylogger running on my PC where I allowed him to access his online wallet).

I think such functionality should be built into the standrd BTC client and not rely on untrusted online sevices.

With such functionality of throw-away wallets the buyer would simply create a new wallet on his USB thumb drive filled with just enough for how much he is willing to spend today, can easily mount it on any BTC client to make a simple transaction and optionally with one click of a button instantly send the remaining money back home to where this portable wallet came from and then simply delete and/or forget about that file because he will never use it again, he can easily create a new on with a simple mouse click.

Additionally there could be a modification to the file open dialog so that when browsing through a folder it would automatically scan though all wallet files in that folder, displaying their balance in a separate column in the folder view.

The temporary wallet file would be the equivalent of paying with paper money: you give a complete 50€ bill to the seller and he will immediately return the change to you and you trust him to not simply knock you down at this point and run away with the entire 50€ bill.

Is this a good idea?


PS:
another Idea (which I also could not find implemented, and I'm not yet sure if it is even technically possible) would be to prepare a transaction, signed and ready for submission to the network but instead saved into a file that I can physically take with me and give it to somebody offline. Like a crossed cheque (payee only). And every BTC client would then also have the ability to read such cheques, submit them to the network and display the results (confirmations or errors). This would be an alternative aproach to solve the above problem. I think (if possible) this method should be implemented also.

If this has been proposed before then please link to the discussion, I have looked around a bit but only found mentions of solutions povided by external online services and I think such functionality should be core functionality of every Bitcoin client.
Pages: [1]
Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2006-2009, Simple Machines Valid XHTML 1.0! Valid CSS!