Bitcoin Forum

It is not hard to find a wallet(the bitcoin address) with enormous amount of money in it.

Its not hard to find a network with enormous amount of hashing power(any pool).

So my question is; How safe is it realy? How long time would it take for a big pool to break a singel address and can it be done?

You can't just access a wallet if you know it's address. You need to know the private keys, which are private.

I know to little of cryptography to even start...

Isnt cracking the privatkey about the same work as we already do?

The vanity thing. its just making random addresses and when you find the right public key you also have the private key?

lol that wallet would be worth "mining"

Bitcoin ASICs can't generate private key / address pairs. They can only mine blocks.

Like I said, pools with their ASICs can't "break" addresses. And even if they could, it would take far longer than it takes the sun to burn out and die. The address space is simply that large.

This doesn't even apply to point groups...just hashes.  I know you still can't get the keys.  Just a question about hash functions in general.

So I've tried to stare at hash code and stare and stare and figure out what actually make its irreversible.  Obviously, I lost track of the bits (I was trying to keep it together up here ->  ;)  but I didn't follow along..lost it somewhere around xor...).

But... is the irreversibility actually fundamental?  if you could ultra slow motion camera the bits literally flipping due to electrical impulses in the CPU, could you not play the movie backward discovering the inverse of the hash?

Parity and time reversal NeOne!?

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Let's see... 150,000,000 keys per sec on a 7970, or 1.5 * 10^8 k/s.  There are maybe 1.0 * 10^8 Bitcoin addresses with unspent outputs.

If I remember right, the complexity of addresses is 2^128.  So, you have 1/(1.0 * 10^8 / 2^128) = 3.4 * 10^30 keys as the inverse of your probability for finding any private key to some unspent output (or basically, your reduced search space after accounting for all keys with unspent outputs).

That's (3.4 * 10^30 k / [1.5 * 10^8 k/s]) = 2.3 * 10^22 seconds to find a single private key to spend a random address' Bitcoins with a single 7970.  

That's only 52,000 * the age of the entire universe, so you should find one pretty quick!

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That's 100m public addresses with unspent outputs divided by the number of all possible addresses including collisions, or more simply the probability of any address of having an unspent output.

edit: Oh, duh, it's the inverse of that, sorry. X)

Why would you even want to bruteforce a wallet anyway? Are you a nasty thief that has nothing else to steal?

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You'd have to do the math but even if 100 billion years pass in a few seconds how many seconds would it take to count to 2^256. Probably a incomprehensible amount of seconds.

Well, bruteforcing one address in 100 billion years might be possible, in fact you may even be able to bruteforce a few more than that.

Might want to rethink that...

115792089237316195423570985008687907853269984665640564039457584007913129639936 addresses

and

3155760000000000000ish seconds in 100000000000 years. I'll let you figure up the rest of the math.

I can crack any crypto wallet in seconds, problem is I can not afford a quantum computer.

In all seriousness, can you imagine one of these bad boys hashing?

http://www.dwavesys.com/en/products-services.html

Quantum computing has arrived, thanks to Canadian ingenuity with funding from the CIA and Jeff Bezos.

Maybe we should start a group funding thread for one:)

Also what happens when someone (government or corporation with deep pockets) turns one of these loose on encrypted 'anything'

I don't think you understand the concept of "...they strongly imply that brute-force attacks against 256-bit keys will be infeasable until computers are built from something other than matter and occupy something other than space."

Maybe, maybe not. But I want one to hash with :)

I imagine in this thread I know the least about the technical aspects of cryptocurrencies and this may be a bit off topic, but when bitcoins reached $1,200 I was curious to know how secure they were, so I gave my kid a task. He had 2 hours to see how many bitcoin addresses he could generate while checking each one for a positive balance. He found 3 accounts that contained many many bitcoins, I was so tempted to take them, that I had to delete his internet history.

He typed long strings of random characters to generate each address.

El oh El. Troll.

I am not trolling

After seeing that, I assume it is very easy to generate addresses that contain coins and that you guys have to be aware of it. I forgot to mention he also found a few accounts that previously had coins too. But like I said, I am not trolling, just sharing my experience with the community.

Um.

http://1.bp.blogspot.com/-m7Qk-A8Q3P4/T9VH8MdS_hI/AAAAAAAAASQ/HSuy6N9-W6I/s1600/3298360470_4983a895bc_o.jpeg

I Really want to build a super GPU computer consisting of over 30 High end GPU's and take everyones BTC. :)

LOL that is obvious, look at your trust rating!

Unfortunately "Einstein's laws of the universe" work precisely the other way round. Bump something up to near lightspeed for however long you like, then bring it back, it'll only have run SLOWER than if you'd left it on Earth.

http://en.wikipedia.org/wiki/Time_dilation

I'm glad I read to the end of the thread before pointing this out too.  ;-) 

Not even close to being a scammer, A scammer buster, I had to give negative to warn the community and I got negative back, Read before talking buddy ;)

Well... you can try to bruteforce wallet if you have enought time...


 
enought time = a few thousand years :D :D

I will have to take out my wizardry book to enhance the GPU's xD

lol :D

But seriously now:

he could do it (in theory) if he has blessing of night mother...
It is like solo mining... you can find block in 1 minute or never :D

You will be happy to know brute forcing takes a little bit longer on the surface of the earth as clocks tick slower here than in free space.

If you sent away a brute forcing computer at high speeds, it would appear from earth's vantage point to be brute forcing more slowly.  So the brute force starship attack by brute speed is fundamentally flawed.

You have demonstrated that random.randrange() can be an extremely poor entropy generator. I hope that no real bitcoin address generator uses that function to generate addresses, though I guess it is possible that someone might use it.

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hmmm.... for starters, randrange() is not a generator.

also, many wallets and tools use that function. One simple example is NoBrainr:
https://bitcointalk.org/index.php?topic=308972.0

I would like to challenge you to "crack" any key generated by it...

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I'm not convinced about your uber hax0r skills but you sure are entertaining ;)

Of course, if you post a proof (other than a funny/shaky/blurry video), I'll review my statement :)

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Good luck with that. :D

This is all well known. (Full discussion in the NoBrainr thread)

It must be a hell of a programmable calculator you have if it can crack that. I want the same one :)

Also I'd love to try out what you're smoking.

(No offense meant, I was also young and naive not so long ago)

You are right. I was being sloppy. The problem is not with random.randrange() specifically, but how it might be used. For example, this is an extremely poor way to generate addresses:


key <- SHA-256(random.randrange(0, 2³²-1, 1))

I'm guessing that this is similar to how the OP generated the addresses that he could easily crack.

Before you start, at least try to figure out how successful you might be: If you can check 1 trillion addresses per second (10¹²), then it will take you only 10¹⁵ seconds (32 million years) to go through the entire space.

No no no, don't you dare bring logic into this!

You are thinking counting in terms of now, you don't know the technology we'd have in 100-200 years let alone 100 billion.

See:

https://bitcointalk.org/index.php?topic=437220.msg4813821#msg4813821

how do you locate Rendezvous addresses?

This whole concept is really, really, flawed. Every single key and wallet ever made can be found at directory.io If you know how to brute force theres your weakness.

Let me give you a hint how to avoid being laughed to in public: Think for a few seconds before you post. If you tried that before you posted this above you would notice there's 121 byte of data in every line on that page that looks like this:
Also you would notice that there are 128 lines per page. The site claims there are 904625697166532776746648320380374280100293470930272690489102837043110636675 such pages in their database. If you multiplied these three numbers you would get:
https://www.google.rs/search?q=121+*+128+*+904625697166532776746648320380374280100293470930272690489102837043110636675 (https://www.google.rs/search?q=121+*+128+*+904625697166532776746648320380374280100293470930272690489102837043110636675)
That's the number starting with 1 and having 79 trailing digits after that. You would immediately realize that mankind would never have database that big and that something must be wrong with your thinking, and you would not post!

Alas, that would have the consequence we would not laugh, which is bad for us, but good for you.

If you know how to launch the Earth away from your PC at near-light-speed velocity, then maybe, maybe. But let's just say, you'd need a very big catapult :D

Also, @itod, I think this site generates the addresses per request. That would make it somewhat plausible.

Of course, serves the next 128 keys no matter what page number you type in URL, you can check. A joke.

Epic. 7.2E23 years.

Yep it proving the that the laws of the universe are in line with bitcoin!

There are so many different possible addresses that for all practical purposes it would be impossible.

agreee anything will bee possible for hacker .
but nor for address wallet .

If it was that easy to hack a wallet private keys,
we would for sure heard this long before your post. ;D

I was messing with the program where you put in a passphrase and it will make a bitcoin address. I actually found two that were used. one passphrase was satasi nakamoto and I cant remember the other one but it was an easy on too. Found that kind of interesting..

Generally, creating a private key from a passphrase is a very bad idea.  Private keys should be created from a cryptographically secure random number generator.

Right, the public key is never supposed to be private. The person you quoted is referring to private keys.

If you use a password that is either very long or created from a cryptographically secure source it should be fine, right? The chance of you brute forcing Ia*1a&5vR9NltU*$Ofl2 is extremely slim. If you can memorize it, the reduced risk of loss probably makes up for the reduction in security, which, while exponential, is still slight for practical purposes.

Public key is private also on unspent address.  This is extra security especially against poor wallet implementations.

Cracking a bitcoin address with CPU is simple but takes a long time. With enough CPU I imagine an address per month would be a decent timeframe.

Google "Vanitygen".

For some values of "simple", some values of "long", and some values of "enough".

In other words, impossible.

Onkel Paul

Per month? I highly doubt it. More like couple hundred years.

Simple? Yes.
In a month? Theoretically impossible.

If you were to combine the computational power of every supercomputer, every computer, every laptop and tablet, every cell phone, every TI 89 calculator, every abacus, and every person on the planet with pencil and paper trying to guess the private key of a certain Bitcoin address would take so incredibly long that you, nor anyone else, could begin to fathom that amount of time.

Lol, just looked at the numbers. It would take my personal gaming computer 9,000,000,000,000 years to crack a private key.

Oops.

Let's look at the math...

There are 2¹⁶⁰ possible addresses. That's 1,461,501,637,330,902,918,203,684,832,716,283,019,655,932,542,976 addresses. Now there are ASIC miners that can compute 1 trillion SHA-256 hashes per second, so I can imagine an ASIC machine that could compute 1 trillion bitcoin addresses per second. That's 1,000,000,000,000 addresses per second. With that device, you could crack most of the 2¹⁶⁰ possible addresses in about 1,461,501,637,330,902,918,203,684,832,716,283,020 seconds, or about 1,112,253,909,688,662,799,241,769,279,083 years.

Now, to be fair, you don't have to crack every address -- just the ones with the coins. I believe there are about 200,000 addresses with a non-trivial amount of BTC. With the device I described above, you could crack one of those addresses every 5,561,269,548,443,313,996,208,846 years, not once a month.

You need someone with a 6th sense. Someone who can see "dead people". Someone who has some sort of little bird that tells them "The private key is ..."

That's the only way you get to "crack" it.

Brute force is never the fastest way. The fastest way is to use the $5 wrench.

http://imgs.xkcd.com/comics/security.png