Wallet Security

[Morbid]

how exactly the backup recovery process work? what if i have several backups but only manage to recover slightly older version. what happens then with funds and blockchain?

[1713997496]

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[1713997496]

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[1713997496]

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[1713997496]

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[Valerian77]

how exactly the backup recovery process work? what if i have several backups but only manage to recover slightly older version. what happens then with funds and blockchain?

Since the wallet.dat only holds the private keys for the addresses you can access all money bound to that addresses. If the version is old and some addresses are missing in the backup version that money will be lost. The blockchain does care about anybody who looses his addresses.

[The 4ner]

Sorry to keep asking the same sort of questions, but...

If I were to have an online computer with a guaranteed clean OS, running only bitcoin-qt, with no other software ever to be installed, how could someone steal my coins?

(Ignoring offline attacks)

Don't mean to sound rude but these questions doing from someone with a high level of activity? Sort of weird.
Having all that experience I would assume you should know most all of this basic knowledge of bitcoin.

[Scott J]

Sorry to keep asking the same sort of questions, but...

If I were to have an online computer with a guaranteed clean OS, running only bitcoin-qt, with no other software ever to be installed, how could someone steal my coins?

(Ignoring offline attacks)

Don't mean to sound rude but these questions doing from someone with a high level of activity? Sort of weird.
Having all that experience I would assume you should know most all of this basic knowledge of bitcoin.

I have never stored a large number of BTC on a PC at home, but this is something I would like to do in the future (I have found blockchain.info with 2FA to be fine so far).

Of course, I understand that all it takes is for some malware to get onto the PC and the coins are gone - what I am trying to work out is if there is a way to run Bitcoin-qt on a fresh PC and ensure that it is impossible for malware to infect it through your actions (or rather, your lack of actions).  If you don't download anything, how can someone gain access? I don't know enough about hacking - can they hack through your router possibly?

This is all good advice: https://bitcointalk.org/index.php?topic=320385.msg3443370#msg3443370

This thread has served as a bit of a thought experiment for me (and hopefully helped some newbies too).

[bythesea]

I use laptop for my wallet transaction and everything else related to bitcoin and transactions. My wallet password has 30+ characters and so on.

[acoindr]

What I'm struggling to get my head around is that I need a 'clean' PC to generate my private keys for a paper wallet, so why not just install Bitcoin-qt and do NOTHING else with this computer, but send/receive transactions?

Is connecting to the internet inherently dangerous even if you don't download ANYTHING?

That depends.

What you're basically asking is if you can have a pet snake and never be bitten. The best way to guarantee that is don't have the snake. Generally speaking, no, you wouldn't worry simply connecting to the Internet. Absent local machine access a hacker needs a machine to "answer" instructions in some way which can be exploited. This might be a daemon running like telnet or a web server etc. There is also software like PC anywhere which allows remote computer control. Modern Windows computers often reach out remotely for "automatic updates" unless disabled. Throw the NSA into the mix and who knows when your computer is being remotely controlled. However, if your machine isn't set up in anyway to respond to network connections, you do nothing via web browser, and nobody inadvertently turns on or installs exploitable software directly your machine should be okay. The uncertainty is knowing no doors exist over time.

[Shallow]

If you intend to store alot of coins in cold storage best not connect it to the webs at all.

[BitchicksHusband]

I'm not an expert on computers but doesn't the brain wallet provide a unique output when somebody inputs random typing like......

3903450EFZDFZOJF3405340F9ZDFF034T038TGERPJEPRFP034FZEFZEF03450324534508ZEFZOFJZ ELFJ345


In other words it would be unlikely anybody else would type that exact code in and get the same brain wallet results?

As Dan said, humans are a bad source of randomness.

For example your string above fails on several levels
- you are using only a very small selection of characters from the available keyspace
- there are several repetitions of sequences

From the line above alone I can conclude you most likely use a keyboard with french layout. Your left hand was hovering slighty above qsdf, your right hand was hovering over the lower part of the numpad, you moved the right hand over to the alphanumeric keys twice (once in the middle of the string and once near the end), you were subconsciously typing on the right hand with a rhythm of thumb-ring finger-index finger (producing the oft repeated 034 sequence), similarily you subconsciously used a rhythm of ring finger - middle finger - index finger with the left hand (producing the ZEF sequence)

Dang, Sherlock!  That's impressive.  Not that you would still crack that in 1 million years.

[The 4ner]

Ha ha! 

[Gabi]

http://www.bitcointrezor.com/

The Hardware Bitcoin Wallet

Sure, 200$ is a bit too much for that 

[bitcoinchecker]

What do you guys think of these ...

http://www.bit-card.de/cards/passphrase-protected-cards-two-factor/passphrase-protected-wallet-cards.html


Are they secure?

By secure, I mean in the process of generating the password/private key using a so-called verification key.

Are keyloggers the only thing to worry about?

[canton]

Demo: http://youtu.be/1pDSzOiFgIk

I really like the overall process you show in the demo, and it's something I might do myself -- but I'm concerned that you're recommending a process in which only a portion of the BTC balance on a paper wallet is 'swept' and the balance is sent back to the same paper wallet. As I understand it, this undermines the pseudo-anonymity provided by using a paper wallet. The instructions I provide regarding paper wallets is:

1) ALWAYS sweep the entire balance
2) If you want to keep some of the balance on a paper wallet, generate a new paper wallet and transfer the coins there.

If anonymity is not an issue, I believe your instructions are fine. But it's worth at least mentioning that this procedure involves sacrificing one of the much-touted benefits to using Bitcoin.

See: https://bitcointalk.org/index.php?topic=139381.0

[HappyScamp]

I'm not an expert on computers but doesn't the brain wallet provide a unique output when somebody inputs random typing like......

3903450EFZDFZOJF3405340F9ZDFF034T038TGERPJEPRFP034FZEFZEF03450324534508ZEFZOFJZ ELFJ345


In other words it would be unlikely anybody else would type that exact code in and get the same brain wallet results?

As Dan said, humans are a bad source of randomness.

For example your string above fails on several levels
- you are using only a very small selection of characters from the available keyspace
- there are several repetitions of sequences

From the line above alone I can conclude you most likely use a keyboard with french layout. Your left hand was hovering slighty above qsdf, your right hand was hovering over the lower part of the numpad, you moved the right hand over to the alphanumeric keys twice (once in the middle of the string and once near the end), you were subconsciously typing on the right hand with a rhythm of thumb-ring finger-index finger (producing the oft repeated 034 sequence), similarily you subconsciously used a rhythm of ring finger - middle finger - index finger with the left hand (producing the ZEF sequence)

I like you!