Bitcoin Forum

Hello,

My name is Ed and I am 40 years old. I learned a lot about Bitcoins and see that many websites have a technical approach and non-technical approach in explaining how Bitcoins work. Also many sites there is a difference between a objective and subjective approach of explaining the details.

I am the kind of person who wants to know exactly how things work. In my work I also attended a 2 week course to protect agains hackers, and learned about public and private keys.

I have the following questions:

1) I found out that the website www.bitaddress.org is the most simple way to generate a bitcoin address and a private key. However, it's a website accessed by the internet and by using a web browser, using an operating system. From my mind, the most secure way of generating bitcoin addresses with the private keys, is on a standalone computer, with no internet access and without any wifi/bluetooth adapters in it. Is there a way to generate my own bitcoin addresses with private keys on a standalone computer ? After that I will print out all the output to paper and destroy the standalone computer.

2) I like the thing about being anonymous. Not that I am trying to hide something, but I do not like the fact that I need to prove that I have nothing to hide. I know that all the transaction data can be accessed by the website http://www.blockchain.info . You can see exactly how many bitcoins belong to an address and all of the transactions.
But let's say, I have a piece of paper with my bitcoin address and private key, I walk into a store and see a product which has a price of exactly the same amount of bitcoins, which is stored on that bitcoin address. Can I just give that paper to that person behing the cashing desk in order to get my payment accepter ? And how long does it take, before I can walk away with the bought product ? I can understand that the owner of the shop, who accepts payment in bitcoins, wants to know for sure that he or she owns the bitcoins.

3) I see a lot of people standing up, saying something about the future of bitcoins. As a result of that the value of the bitcoin in Euro's or Dollars, will vary a lot. What do you think about people who are trying to predict the future about bitcoins with big words ? Or is it just all speculation ? Or do you think there are too many powerfull people who try to say something, don't have any idea they are talking about ?

Hopefully you give me a lot of info I can think about the coming days.

Thanks a lot in advance,

Ed

Ha, reminds me of movie "Mission impossible"  :)

Remove HDD and boot OS from live CD. No need to destroy the computer this way unless your very paranoid ;)

All of the generation is done client side.  You can (and probably should) save a copy transfer it to an offline computer (or disconnect the computer from the internet) and generate your paper wallet.

The generation doesn't require any internet access.  Destroying the computer is likely overkill.  As pointed out if ultra paranoid make a Linux Boot OS on a Live CD and include the (offline copy ) bitaddress webpage.

Boot, generate, power off.

You would never share your private key with anyone. With that key anyone can control any bitcoin associated to it.

If you dont want your balance to be online, use coinbase. Since they have internal transactions, they dont get logged on the blockchain so its impossible to know what your balance is exactly.

No you cannot give the piece of paper since you might have a copy of the private key. If you have the private key, you can just use it to send the btc to another address before the cashier can do it.

If you are so paranoid you may want to remove the speakers as well
http://arstechnica.com/security/2013/10/meet-badbios-the-mysterious-mac-and-pc-malware-that-jumps-airgaps/

Thanks a lot for answering me, it clearifies a lot for me.

1) simply access the website bitaddress.org,
then disconect from the internet. 
then generate your private key. 
now store your private key offline somewhere.
now close your browser.
now reconnect to the internet.

@jixin55 :

It seems to be very safe, but how do I know for sure that there is no virus/malware/spyware on my PC, which is checking exactly what I am doing ?

Download Ubuntu. Burn it to a disk, and boot from it. Then click the button that lets you try it out (don't install it). Then do as mentioned above.

Not much safe, download bitaddress.org to usb stick, remove HDD, remove lan cable and boot from live Cd, then generate your private key in offline

I would say that thats a little too extreme!

Just whatever you do, don't make a password so f'in complex u wanna crack your head open after u can't memorize it the next evening

Although, this may be a cool way of payment in certain situations. It would be a lot easier for you to just send them the bitcoins through a transaction, and you wouldn't need to kill a part of a tree.  Handling your private key to them will not negate the fact that you can easily copy it down more than once, or it could just be a fake.

Yes. Maybe in the future there will be some sort of system where you can transfer btc on the spot and securely. That way no one is at (unfair) loss.

just create a new address for each transaction for send and receiving if you want

I heard people suggesting destroy the laptop and printer after the private key is printed
I would say this is extreme!

Ya, but there is no need of taking out the hdd. Obviously you have to take out the lan cable. Also you can pretty much use the browser in the live cd and disconnect from it once you load the site.

You can, unless you get hacked and infected while downloading the page.

Hi Ed my name is Ed too

I think there is a lot of overkill on this. I've been involved with IT since 1986 and one thing I know of a fact is that hacking takes time and money. NO one is going to spend more time and money then it would take to mine bitcoin just to grab a few mBTC's. If your wallet is off-line don't worry about it. All this "booting" and other nonsense is just not necessary. Just place your wallet in an external HD and disconnect whenever you are not using it. Then let time take care of security. Meaning that this is open source, better security options are and will be developed as bitcoin matures. Just make sure you have a good password.

You never heard of keylogers ? Disconnecting helps nothing. And most computers are compromised in some way, people downloading, installing and browsing shit very often. The AV protection is just joke, and a false way to feel safe

If its in the hardware you cant do anything but throw away your keyboard, but if its a software just use a Ubuntu live disk and you will be good.

@majorX I am not say to not protect yourself. But fostering such ideas as bitcoin needs to kill HD's just for protection is wrong. If you leave your leather wallet just sitting around someone will take it and you will lose. Your bitcoin wallet is the same, you need to take care of it. But how much is overkill?

How about this, since you can have as many wallets as you want why not make as many as you want and keep less than .00001 in each one. Then when you want to make a transaction combine them for that transaction only.

In all seriousness is there a way to do this? Spread 0.001 btc over multiple addresses and then combine them?

There is now, I see from your website you are working with the API's. Go to it and make your millions!

Possible, but the fees would be high. If paper wallets used for 0.001 btc / address it would be a lot of work  :)

Dont seem to understand how my programming skills have anything to do with this if there is a software available. Can you please tell me the software that does this?

Kind of my point to begin with, yes there are bad apple hacking addresses and wallets but the time and resources involved it's easier to just trade. Now this will be a different story if we see the highest of lets say 1 BTC = $47,000 but by that time someone will build counter measures. That is unless you have dozens or hundreds of BTC. Then you can be darn sure someone is watching your every move.

Your programming skills? This is open source! I was implying for you to "write" it. I would use C++

just adding some more options.
if you have a standalone computer that doesnt touch the internet then here's 2 ways.  they also work similarly for alt coins.

1) goto bitaddress.org.  follow link on bottom of page to github to download the source.  copy over the github source (sneakernet/whatever you feel comfortable with) and open the webpage.  generate your required addresses and keys.

2)grab bitcoin-qt client (sneakernet/whatever you feel comfortable with), install.  under receive address tab create new receive address or select existing one (name is irrelevant here). right click on the address and select "copy address".  Goto help->debug window->console tab. inside the console tab enter "dumpprivkey [paste your btc address here]".  the console will spit out your private key.

if you leave you computer standalone, then you can continue generating addresses and private keys at will.  only hole in the chain is what medium you are using to get your priv key data and receive addresses out

Thank you all a lot for responding.

It is now very clear how to generate a bitcoin address with private key, so that I will be the only one who knows the private key.

How random will those bitcoin addresses with private keys be generated by www.bitaddress.org .
On other words, is there a way that I can reproduce the same bitcoin address with the same private key. Let's say I do exactly the same mouse movements at exactly the same system time ? Or what are the variables for the private key generation ?

Is there a webpage or program, in which I can give my private key, to see my bitcoins address ? I mean when I lost the bitcoin address ?
Can I see the bitcoin address as private key ? I just try to understand the public key / private key mechanism.

Nonono. You never want to give someone your private key. Not on purpose anywya  ;D

you can use one of the block chain explorers to see the transactions and balance of your payment address

if you lose ur payment address but still have private key, simply go back to console of bitcoinqt and enter
importprivkey ur_priv_key

and it will import your key into your local wallet and you can then view and copy the payment address

Best way to know everything about it, is to actually build a program that uses it. Well, that's my opinion.
You can use Vanitygen. But destroy your computer is overkill. You should protect the private key or, if you use your own bitcoin client, a wallet file, but a lot of sites are pushing the security a little bit too far.
It will work, and a few confirmations should be enough. But it's a little bit cumbersome. If you really care about being anonymous, just send it from a blockchain wallet with shared send.
Don't listen to them. Nobody can tell for sure what is going to happen. Do your own research, just as somebody would do when trading stock. Things should be valued what it's really worth, so look at the real value of a company, what's the profit, what's the sales, etc. The rest is all speculation.

No, you can assume you never make the same private key.

Generation is only one way, so:
private key => public key => address
If you only have the private key, you can always calculate the rest.

Welcome to the forum, and enjoy reading. ;D

Go to bitaddress.org
Disconnect the internet
Then generate public and private addresses, and print them (maybe several copies)
Then erase the history on your computer.

If you have a private key, you can derive the public key from it. You can do it here:  http://brainwallet.org/
Use the generator and select generate from private key, this will show your address. This works offline as well. You will always get the same address from a private key, the randomness is used to create the private key. I highly doubt they only use the mouse movements/system time, most likely they are just used as additional sources of unpredictability to be used as a seed or maybe the random data is XORed with those, whatever. I would think the site tells you that somewhere, I did not check.

PenandPaper posted a very interesting story:

http://arstechnica.com/security/2013/10/meet-badbios-the-mysterious-mac-and-pc-malware-that-jumps-airgaps/

What's the cheapest possible computer I can buy, to run the webpages offline on, to generatie my bitcoin addresses and private keys ? Raspberry Pi ?

Then I will put those addresses on an usb stick, which ones are the best I can trust ? Were there any new USB sticks on the market, which had hidden malware already on it ?
Sometimes I see Western Digital hard drives, with extra software already on it installed. I really do not like that.
Which ones are really totally empty when I buy those ?

Same for empty recordable CD-R's and DVD-R's, when I read the story posted by PenandPaper, a lot could happen.

I know for sure, that a piece of A4 paper, does not have hidden hardware in it, 100% sure.
But we cannot be 100% sure, when we buy empty recordables or empty USB sticks, you can call me paranoid, but just want to be 100% sure.

Do not. Print the address and qr code instead. If you need the address on online comp, jut scan the address qr code

1 golden bitcoin advise, DO NOT USE BTC-E.

They have stolen and scammed my money, but I will fight them on these forums to let people know what they are doing.

I was going to suggest Raspberry PI to you. That is good and you can also probably think of other things to do with it also. Just use paper, write down the private key and store it in a safe place (bank vault?). Preferably two different banks, or more.

What I would actually suggest, since you seem to be security-conscious, is to use a brainwallet. Come up with a secure (!!) phrase and use that to generate a private key (and an address). Send the bitcoins to that address. The private key will not be anywhere. When you want to use your coins, just generate the private key again from the secret phase. You don't seem stupid so you can probably think for yourself if you are able to
a) come up with a secret phrase NO ONE can guess, such as "ED's seCCCret fraze bunny-hop 11100 ostRICH T 4 tango", or something more sensible but with around that much entropy
b) be able to remember that phrase, no matter what (avoid applying blunt force to head)

Then it's pretty safe and you could travel accross the world, carrying your Bitcoin wealth in your head without anyone knowing about it. Which I think is kind of neat.

Please don't let the username fool you,I am not rich in bitcoins or anything else save my family and my health.
That being said,the more I read and try to understand all things Bitcoin the more confused I become
I fully support the concept of currency not tied to central banks or govn't entities but to have to worry about cybertheft of Bitcoins is clouding my thinking.
Call me old fashioned but things like gold while being cumbersome to transport and purchase smaller items with is at least a tangible good,something I can hold or hand to you.Should you wish to take it from me at least I could physically defend from that threat.
I joined the bitcoin forums thinking I might find a buyer for a classic muscle car I own .And said buyer could simply buy at some preset rate.
I guess the question I have is ,like Ed,should I worry about the safety of such a transaction

this thread was helpful for me too.

How??

This is sound advice.  If you're Mt. Gox, then you should be paranoid about being hacked.  But Joe Blow?  Unlikely you'll be a target.

If you're really paranoid however, check out the below story... "the walls have ears" as the Persian saying goes.

TT

http://www.theregister.co.uk/2013/12/19/acoustic_cryptanalysis/

Code-busters lift RSA keys simply by listening to the noises a computer makes