Bitcoin Forum
September 24, 2023, 11:05:58 PM *
News: Latest Bitcoin Core release: 25.0 [Torrent]
  Home Help Search Login Register More  
  Show Posts
Pages: [1] 2 »
1  Bitcoin / Hardware wallets / Safest way to get funds from an old QT-Wallet onto a Trezor? on: March 09, 2015, 12:27:23 PM
I have an old encrypted QT-wallet with a substantial amount of BTC on it. I also have a new Trezor that is configured and ready to receive funds.

I want to move the funds from my QT-Wallet onto my Trezor without any risk of losing the funds. Thus, I don't want to decrypt it on any computer that is connected to the internet.

My best option as far as I can see is to import the private keys to an offline computer with Armory, then use offline signing to send the funds to my Trezor.

Is this my best option? If so, is there anyone who have some experience with importing keys from a QT-wallet to Armory and could guide me in the right direction?
2  Bitcoin / Bitcoin Discussion / Questions Regarding BIP32 Security on: February 20, 2015, 06:32:36 PM
I'm trying to wrap my head around the security implications of HD wallets. The vulnerability I'm a bit unclear on is where a private key and a master public key together can leak a master private key.

As far as I understand HD-wallets, they consist of a pair of master keys, derived "account master keys", and then a pair of keys for every single address in every account. Say my xpub master key is known, what would someone with a single private key be able to do with this? My guess is that he could get the private account key, thus getting access to all the coins in that account, but not any other accounts. Correct? Any other things I should be aware of?

Secondly, apparently there is this thing called hardened keys as well that makes this leaking impossible, which is why it is isolated to single accounts. I assume there is some sort of drawback of this, since otherwise all keys should be derived in this manner. What's the deal here?

If there is any other non-intuitive possibility of leakage of private keys that I'm unaware of, please tell me.

3  Bitcoin / Bitcoin Discussion / Recurring payments on: May 08, 2014, 06:19:20 PM
The topic of recurring payments came up on reddit regarding Github subscriptions. So I started to think a little bit and wondered what the plans are for this. Currently some services such as Coinbase apparently offer this but it would be good if the Bitcoin ecosystem offered some standard way to do this, in order to not lock people up to specific companies.

First, if there has been any discussions on this previously someone could please link it to me.

I think we need a standardized adress book in order to seemlessly make this happen.

Say I would like to subscribe to an internet service. Ideally, it should be as easy as clicking on a link to download all the information for the recipient and store it in my Bitcoin client. The Bitcoin client could then tell the user when a payment is coming up, and the user can choose wether to pay the bill or end the subscription.

There are a few things that this adress book needs. It needs the name of the recipient, some information about the subscription, a seed that lets the user generate new adresses by himself and preferably a link that lets the client look up the current price in BTC and any other info that may change every time a payment needs to be done.

If a user of a service had all of this information stored locally, subscriptions and bill payments would be as easy as opening your client and click a button that acknowledges the transaction. The user could also set it to allow automatic payments to trusted services.

Unfortunately I'm not good enough on the technical side of things to really speak about how this would best be implemented. So this thread is about general discussion on how to best allow recurring payments in the bitcoin ecosystem in a standardized way. It seems to me that there are two important things to allow this. A standardized way to add recipients in the Bitcoin client such as a contact csv file with some extra fields for bitcoin information, and a standard for internet services to let the users look up information that may change from payment to payment (such as the BTC denominated price).

4  Bitcoin / Bitcoin Discussion / It's bits. on: November 28, 2013, 11:02:31 PM
I saw this post on reddit. All credits to original OP.

I couldn't agree with this post anymore. The SI-prefixes simply aren't catching on, even though I've seen people pushing for them for 2+ years and the fact that mBTC has been somewhat useful for about 1 year.

A "bit" is a simple memorable one-syllable word that has the possibility to catch on. Can we agree on something that works?
5  Economy / Speculation / Is SecondMarket buying bitcoins? on: November 06, 2013, 11:57:44 PM
I believe I stumbled upon some interesting numbers here.

According to SecondMarket's investor presentetion here (page 11), they owned 37 500 BTC as of November 5th:

However, according to the end of the following news clip, they have already taken in 15 million USD in investments (more than expected).

If we were to count with an average price of 200 USD/BTC for their sales, that would add up to 75 000 BTC. Even if we assume all their sales were at the current prices, it would add up to 56 000 BTC. Regardless how you cut it, the math doesn't add up. So my conclusion is that Second Market already are, or soon need to be buying BTC again in other markets in order to keep up with demand.

Your thoughts?
6  Economy / Goods / Philips Hue starter pack + 1 extra bulb on: May 17, 2013, 05:15:44 PM
During a spending spree in the states I recently managed to aquire, among other things, some Philips Hue lightbulbs. However, for reasons I'd rather not state (I'm simply stupid), I didn't really think about the fact that they won't work back here in Europe with our 220V jacks. So I have no choice but to sell them back to the states.

For those who don't know what Philips Hue is it's light bulbs that you can dim and change colors that are controlled via wifi.

See this video:

They are currently only sold at Apple:

So what I'm selling is the starter pack with the control unit and 3 lightbulbs + 1 extra bulb for a total of 4 bulbs. The packages are opened but never used.

They are yours for a bitcoin amount corresponding to 200 USD at the time of purchase (costs ~260 USD in store). Shipping is on me. I can ship first to a trusted user, otherwise I'll require escrow.

First come, first served.
7  Bitcoin / Armory / Can Armory import QT-wallets? on: April 20, 2013, 04:59:28 PM
I currently have a bitcoin-QT client with an encrypted wallet. The password is strong enough that I don't need to worry about anyone stealing my coins even if they get access to my machine. However, with the current price increase I'm becoming a bit paranoid about using the wallet. In fact, I don't feel comfortable to ever decrypt it in fear of having a key-logger on my machine.

This question is mostly for future reference. But what I would like to be able to do is to buy a cheap computer and move my wallet over to it. Then I would like to import it to Armory and use offline transactions only from that point on. Is there a way to do this relatively easy right now?
8  Bitcoin / Press / 2013-04-11 CNBC adds a Bitcoin ticker on: April 12, 2013, 08:02:20 PM
9  Other / Meta / The Bitcoin Forum should have Ads on: August 01, 2012, 04:39:40 PM
Do you think it would be a good idea if this forum was providing free ads for bitcoin businesses? This forum is definitely one of the most visited bitcoin sites, and we all here have an interest to not only spread awareness of bitcoins, but also about the lesser known businesses and websites that accept bitcoins.

There is an issue of how to choose which site should get the ad space, but I think there are fair ways to do this. It could be set up like an award and every month a new company or someone who has done something special for bitcoin would get the honor to be featured on the site until the next month. Or we just give the space to someone with a unique idea and needs the exposure. My first thought here is (I'm not affiliated with them in any way). I think they have a great idea but they really seem to need a way to get the word out to people.

This could be a great way to help lesser known businesses or to incentivize people to do something for the sake of community to win the ad space. What do you think?
10  Bitcoin / Bitcoin Discussion / Mining pools as payment processors? on: February 12, 2012, 10:54:15 PM
The idea came to me when I read the TOR thread about trading mining hashes rather than actual bitcoins to incentivize TOR nodes in a more anonymous way. I'm not sure it's entirely feasible though so I need some input on the idea. But lets say a pool started an internet wallet service where you can deposit bitcoins. You deposit 10 BTC, and the pool credits you with future proof of work worth of 10 BTC. When you want to spend your bitcoins to someone else you get a bitcoin adress, give this to the pool, who then diverts 10 BTC worth of hashing power towards this adress (minus an arbitrary fee). The 10 BTC you initially deposited would be used to reward the miners so they don't lose anything from diverting the hashing power. Once you get the hashes, you give these to the person you wanted to pay who can check their integrity to know their value. (and that person may actually be part of a pool himself and relay the hashes to it so he gets bitcoins without variance).

I have no idea if this is actually a good idea or even technically reasonable, but it seems to me like this would be a way to remove the block chain link between payer and payee. The payer would only be linked to the pool he deposited at. The pool wouldn't even know who it is contributing hashing power to. And the payee would get newly minted bitcoins straight from a block reward, or from another pool.

Now is the time you rip this suggestion to pieces.
11  Bitcoin / Bitcoin Discussion / What about bitcoin containers? on: December 29, 2011, 12:37:38 AM
There is an issue with bitcoins, which is that you always need to communicate with someone and recieve an adress before you are able to send them any bitcoins. This is opposed to regular cash where you can leave it somewhere (like under a door mat, or in someones mailbox or wherever depending on the sum and security needed) and have someone pick it up later. In the digital world this would be achieved if we had a standardized way to send someone bitcoins regardless of the way we communicate. We should be able to send bitcoins over e-mail, http, sms, or really any way we want as long as we have some way of sending a message, even if it's just one way communication.

I've seen some ideas to provide this for e-mail through third parties, but I really think such a fundamental service could and should be provided at a more basic level.

There is a way to do this right now though, by creating a new wallet that contains some bitcoins and send it to my friend, but it is really cumbersome at the moment, and intuitively there should be a difference between wallets and spare cash. My idea is to use a new file type, called a bitcoin container with the file ending *.btc. Technically it would be a small wallet with only one key-pair, but once it is opened by a client, the client simply sends the money to the user's wallet and informs the user "X btc added to your wallet."

An example of how neat this could become. Say I want to send my friend some cash, but doesnt have any bitcoin adress of his. Instead, I go into my android btc app that uses the android share api and I press share via e-mail. The android client then creates file.btc, it sends a chosen amount to the new adress, withdraws it from my balance in the app, and enters my e-mail application with the new file attached. So I e-mail my friend who recieves the money and simply opens the file to put it in his own wallet with.

Preferably, you should also be able to protect these containers with a password. That would also provide a fairly easy way to store parts of your own btc outside of the client in a secure manner. Simply create a btc container from the client and choose to save it on a usb drive. If you use an android app you could send it directly to drop box via the share api etc.

12  Bitcoin / Bitcoin Discussion / Can you put a deadline on a transaction? on: November 27, 2011, 01:24:26 PM
Can you say something like "this transaction becomes void at block X" so if it's not put in a block before then it becomes useless?
13  Bitcoin / Bitcoin Discussion / Virtual bank notes, 100% backed by bitcoins, enforced by smart contracts. on: November 02, 2011, 12:30:26 AM
Basically, I've been trying to come up with ways to securely remove what I believe are the two biggest disadvantages of bitcoin, the wait for confirmations and the transaction history in the block chain. The idea I have (I've seen variations of it elsewhere as well) is to solve this by stop trading bitcoins altogether, and start trading ownership of bitcoins instead. This obviously creates some new problems though, especially in terms of trust in whoever is in possesion of the actual coin. But I was hoping that the trust issue could be resolved using the smart contracts feature of bitcoins. So in this thread we discuss every way that may be possible.

Below are my thoughts on one way that this could be possible. Although first a disclaimer, I'm not an expert in the details of cryptography in any way, but I do believe I have a pretty good grasp of the logic behind it. My proposal may be flawed or bad from a technical view. If so, feel free to improve or disprove it.

One way this could be achieved is by creating "virtual bank notes" that simply represents ownership of a bitcoin stored at a "virtual bank". These bank notes could then be exchanged between people without transactions actually taking place in the block chain (not entirely P2P though, see further down). This would be very similar to real bank notes backed by gold and issued by private banks. There are some differences though, and the most prominent one is that the nature of bitcoin could make fractional reserve banking impossible. Upon recieving a note you could simply look up the specific coin in the block chain to make sure that it is where it should be.

Another difference is that the pseudo-anonymous nature of bitcoin means that the incentives for the bank to simply run away with the money is a lot higher than in real life. So this needs to be solved by the smart contract feature of Bitcoin. Lets say you want to make a deposit to a virtual bank and recieve a virtual bank note (lets call them bitnotes from now on) in exchange. This would be done by you making a transaction that needs both the bank and you to sign the output in order for the bitcoins to be spent again. This means that the bank can't steal the bitcoins from you, and you can't steal it from the bank either. After this, you recieve the data you need to create your first bitnote. The bitnote contains at least the following: 1. The private key that you have and the bank needs to spend the bitcoins, and 2. A secret identification that you need to proove to the bank you are the owner of the deposited bitcoins.

So now you want to pass this bitnote on to someone else. Easy, you simply send him your bitnote with the private key and the secret ID. This means he could withdraw the bitcoins just as easily as you. However, he doesn't want to withdraw it, he only wants to stop you from doing it. So he contacts the bank, tells the bank the secret ID and recieves a new one. So now the bank knows that you are not the owner of the deposit anymore. So even though you still have the private key that could be used to sign a new transaction of the bitcoins, the bank knows you are not the owner and has no reason to allow you to withdraw by co-signing your transaction.

The idea here is that the bank can't spend the bitcoins it has in possesion without the private bitcoin key in circulation with the bitnote (thus minimizing the need to trust the bank), and that it won't spend it even if someone would provide them with the key without prooving that they actually own the funds too. I realize this is not bullet proof protection against theft though. If you recieve a bitnote, the bank could thoeretically still run of with your money, but only if it managed to collude with a previous owner of the bitcoin that you currently have claims on. This still greatly reduces the incentives though since it makes it really hard for the bank to ever get away with more than a fraction of all of its clients money, since that would require collusion with a lot of its customers. The bank never has the choice between stealing every customers money and continuing business. So the incentives to continuing business as usual are much higher than it is for current "virtual banks" such as MyBitcoin.

I really have no idea if this is among the best ways to achieve what I want (Instantaneous invisible transactions). So really, any proposals on how smart contracts can be used to make anonymous full reserve banking work better is welcome in this thread. My proposal is just a start for the discussion. I really hope the interest in something like this is high here, and if my method could be improved noone will be happier than me.
14  Bitcoin / Bitcoin Discussion / BayFiles - New uploading site from the people behind Piratebay on: August 30, 2011, 09:00:43 PM
Get them to accept bitcoins! Considering that they seem to be quite open to new technology and that Bitcoin is quite popular in the pirate scene it shouldn't be impossible. Since they are new they will probably appreciate the attention that this could bring them as well. So send them a feature request at their site. I already did my part.


I was wondering if you have any plans on providing payment in bitcoins. I believe bitcoin is really a suitable payment system for this kind of service, since it provides near instant micro-payments for a very low fee.

Also, it seems that some of your competitors have taken notice to this and are already starting to make a move to allow bitcoin payments.

15  Bitcoin / Bitcoin Discussion / Can the same bitcoin be spent twice (or more) in one block? on: August 23, 2011, 10:37:29 PM
Lets say my friend calls me and needs some money fast. I send him some money from my smart phone, he recieves it and says thanks. Then he wants to spend it on whatever he needed it for. Assume that he spends it before he gets any confirmations, is it possible for both of our transactions end up in the same block?
16  Bitcoin / Bitcoin Discussion / What to do about missing bank withdrawal from Mt Gox (almost two weeks) on: June 21, 2011, 05:34:11 PM
Considering what happened this weekend I haven't really wanted to bother MagicalTux with this issue yet. But I still feel like I need to get some input on what to do right now, since I really don't want this to get lost in the mess.

Basically, I withdrew almost $800 to my European bank account from Mt Gox about 2 weeks ago (Thursday, I think) and I still haven't recieved them. I meant to e-mail Mt Gox yesterday, but considering what happened I decided that my mail would just get lost in the mess, and that I would be in the way of cleaning it up. But now the claim page is up and accounts are about to get recovered so I really need to think about this. What would you do? I'm thinking of mailing them as soon as I get my account back, since it feels kind of pointless before then. Do you think they will actually have time to look into this right now? I really just want to make sure that this issue doesn't fall between the chairs.
17  Bitcoin / Bitcoin Technical Support / [SOLVED] Transaction not sent to the network (it seems) on: June 08, 2011, 07:47:12 PM
In short, the problem seem to be that my client believes it has broadcasted a transaction to the network while the network doesn't seem to have recieved it. So how do I "re-broadcast" this to the network?

It's a 33 BTC transaction to 13L7sQqXELU8xuwBjMqb8uDUqNojtpiHY btw if anybody wants to look it up.

Edit: I should really search first. Anyway, I found another thread that says the client will try to resend the transaction every couple of days though. This is kind of bad though since the transaction is going to Mt Gox and the adress is only usable for 24h.

I'll try to obsessively restart my client as mentioned in the other thread and hope it works, but if it doesn't I think this really needs to be solved before the Mt Gox adress expires.

Edit2: Yes, it does seem like obsessive restarts solves the problem :-)
18  Bitcoin / Project Development / Need input on a project on: June 06, 2011, 02:27:23 PM
I'm thinking of developing a site (paying for the development since I'm not that code-savvy) that will need the use of a bitcoin-daemon and a system for deposits/withdrawals and someway to send money between different customer accounts to work, and I need some input on the best way to solve some of the issues I have about this.

Basically, I need a way to let customers be able to deposit and withdraw bitcoins on demand, and also send funds between them. The way I have thought of this is to use a web-frontend to the bitcoind, and give every customer a single adress that will be used to deposit funds. All funds that are sent to a specific adress will automatically be credited to that customer and kept track of in a database. If money is sent to another account, the database will keep track of the difference without actually making any transaction in the bitcoin network. This means that funds could be instantly transfered between accounts without actually relying on confirmations and such. However, once someone wants to withdraw their funds, the balance of their "bitcoin deposit adress" most likely won't be the same as the balance in the internal database. So with this solution, it becomes neccessary to let them withdraw from other bitcoin adresses as well, and the server need to do some internal control to make sure that they don't withdraw more than my database says they can.

This the easiest way I thought of to get the result I need. But I would really like to have some input on the pros and cons of this method from some more experienced users. Is this the way you would implement this or would you go about it some other way? Any input on things I may not have thought about is also appreciated.

Also, I do not have the resources to host this site myself, so I will need to pay someone else to do this. My goal is to try to find someone willing to host both the web site and a corresponding bitcoind. The web-site will probably be in the grey-area of the market (as a lot of bitcoin activity seem to be) so this brings up two potential issues. First, I want to make sure that I will be able to find someone to host this site + a bitcoind for me. I don't think this will be that hard but I just want to make sure before paying for the development of the site. Second, and this is probably my most important question, if someone else is hosting everything for me, I want to make sure that the person who has physical access to the server doesn't have access to the wallet containing all my customers funds. I really don't know how to solve this problem. I assume that it can be solved by cryptography somehow, but I really need to check with you more knowledgable guys before going further with this.

Thanks in advance.
19  Bitcoin / Bitcoin Discussion / What happens to mining with a sudden drop in value? on: May 30, 2011, 09:03:33 PM
So I just thought of something. Assume that we have reached some sort of equilibrium in the economy. Miners earn just slightly more than their cost of electricity. Then assume that we have a sudden decrease in value for whatever plausible and unforseen reason. As I have understood bitcoin, the difficulty will only change every 2016 blocks. Isn't it possible that we get a situation where mining could actually be unprofitable for everyone except those with free energy until the next difficulty change? This would create a prisoners dilemma situation where basically no one has an incentive to mine, but everyone gains from other people mining (since the new difficulty would come sooner).

20  Bitcoin / Bitcoin Discussion / Glitch on bitcoinwatch? on: May 26, 2011, 06:57:03 PM
So basically the entire network just got quite a bit bigger by 3000 Ghash/s. This can't be true right. And if it is is what seems to be the cause for this sudden and extreme new hashing power?
Pages: [1] 2 »
Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2006-2009, Simple Machines Valid XHTML 1.0! Valid CSS!