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Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

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Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#11

Post by hrehhf »

TheDong wrote: post #8
hrehhf wrote: post #6

It appears that they are finding the private keys for transactions that already occurred. Reusing an address is not part of Bitcoin's design and it was never intended for people to do that. By not reusing addresses (not reusing private keys) I think one would be immune to this attack. The article doesn't seem to have much detail; anyone have more detail on this? Edit: The details are in the URL posted by alphydan; it…

To receive anything, you must have an address (the public key). All coins (UTXO) are associated with addresses which must have private keys. It's impossible to only have a public/private keypair for the instant a transaction is being made because the UXTOs must be owned spendable by some public/private keypair while a transaction containing them is not immediately happening. You clearly don't understand what you're t…

You have ignored the difference between an address with has never spent anything and an address which is being reused. Since you know everything, why not address this directly?

edit: Though unrelated to this article, here is a case where address reuse (and software bugs) led to vulnerable wallets: http://www.nilsschneider.net/2013/01/28/recovering-bitcoin-p...

Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#12

Post by andy_ppp »

api wrote: post #5
josst wrote: post #4

Earlier quoted context omitted.

Bitcoin is finite and one would expect the supply to become smaller over time thanks to keys being lost or owners dying and their accounts being inaccessible. In the long term guessing keys may be the only way to obtain new coins.

The new mining... This would basically make Bitcoin Keynesian, since coin stored in wallets would now decay with a given probability. So you would have to invest it at least a little to beat the decay (shrinkage) rate.

This assumes an end to speculation which IMO will always exist.

Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#13

Post by SomeStupidPoint »

Bedon292 wrote: post #2

Very interesting work. 3 Quintillion keys generated, 3 private keys with coin in them. I have to wonder what processing power is being put into it, and if that power would be more effective at just mining coin, if someone were just after the money. At least in the short term. I think in the long term attacks like this might become more and more prevalent. Because at some point it may be easier to do this than mine ne…

Small note, but 3,000 trillion is 3 quadrillion, not 3 quintillion. Which is their total, over a significant amount of time.

The bitcoin network does over 3 quintillion (>3,000,000 trillion) hashes a second. So even if they were doing a significantly harder to compute hash -- they're still only a very small part of the computational power the bitcoin network is using.

So it's probably already more effective to attack wallets than join a mining pool.

Ed: Estimate of numbers --

Assuming that their hashrate was over 3 months (article says nearly a year, but they're also scaling), they had about 300 million hashes per second. Bitcoin had 3 million trillion hashes per second over the same period. So you're talking 1 to 10 billion in raw hashrate, and even with a generous challenge factor, bitcoin is using millions of times more compute power.

There were about 150 thousand bitcoins mined over that period, so 1 in 10 billion of that is 0.000015BTC.

Since they hit 3 in use accounts with the same compute effort, they almost certainly made more BTC attacking wallets with collisions.

Ed2: How much parasitic hashing --

If you figure the average active wallet has between 1 and 5 BTC (very high variance), and the wallet hash takes about 100x as long (over estimate), they made 3-15BTC vs 0.015BTC by attacking the network versus mining, or about 200-1000x as much.

Since colliders are themselves unlikely to collide (and thus competition doesn't starve out colliders), the system will only stabilize if 99%+ of miners drop out of the pool or the difficulty in finding a collision raises 1000x.

Given the sunk costs in dedicated mining rigs and that new hashes would be breaking, it seems like parasitic hashing will continue to be an issue.

On the plus side, only a one-in-a-million chance it wipes one of your accounts.

(Of course, a fluke collision with a high value account might create other problems.)

Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#14

Post by xseven »

josst wrote: post #4
Bedon292 wrote: post #2

Very interesting work. 3 Quintillion keys generated, 3 private keys with coin in them. I have to wonder what processing power is being put into it, and if that power would be more effective at just mining coin, if someone were just after the money. At least in the short term. I think in the long term attacks like this might become more and more prevalent. Because at some point it may be easier to do this than mine ne…

Bitcoin is finite and one would expect the supply to become smaller over time thanks to keys being lost or owners dying and their accounts being inaccessible. In the long term guessing keys may be the only way to obtain new coins.

Not true. Mining at later stages will provide miners with transaction fees which will be significantly high enough for them to focus on keeping the network secure rather trying to find colliding keys

Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#15

Post by chejazi »

Not sure their what their heuristics are for narrowing the search space, but there certainly are some good ones. For instance, early versions of blockchain.info's wallet generated private keys by reading an ARC4 stream that had been seeded with Math.random() calls xor'd with timestamps. Quite the circus!

Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#16

Post by csomar »

hrehhf wrote: post #6

It appears that they are finding the private keys for transactions that already occurred. Reusing an address is not part of Bitcoin's design and it was never intended for people to do that. By not reusing addresses (not reusing private keys) I think one would be immune to this attack. The article doesn't seem to have much detail; anyone have more detail on this? Edit: The details are in the URL posted by alphydan; it…

Even more important, by reusing addresses you are making more signatures using the same private key. This has proven to be a vulnerability where one can deduce the private key from these signatures (though limited to a bad implementation) but it's worth considering.

Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#17

Post by xseven »

SomeStupidPoint wrote: post #13
Bedon292 wrote: post #2

Very interesting work. 3 Quintillion keys generated, 3 private keys with coin in them. I have to wonder what processing power is being put into it, and if that power would be more effective at just mining coin, if someone were just after the money. At least in the short term. I think in the long term attacks like this might become more and more prevalent. Because at some point it may be easier to do this than mine ne…

Small note, but 3,000 trillion is 3 quadrillion, not 3 quintillion. Which is their total, over a significant amount of time. The bitcoin network does over 3 quintillion (>3,000,000 trillion) hashes a second. So even if they were doing a significantly harder to compute hash -- they're still only a very small part of the computational power the bitcoin network is using. So it's probably already more effective to attack…

Multi-sig is the cure :)

Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#18

Post by csomar »

SomeStupidPoint wrote: post #13
Bedon292 wrote: post #2

Very interesting work. 3 Quintillion keys generated, 3 private keys with coin in them. I have to wonder what processing power is being put into it, and if that power would be more effective at just mining coin, if someone were just after the money. At least in the short term. I think in the long term attacks like this might become more and more prevalent. Because at some point it may be easier to do this than mine ne…

Small note, but 3,000 trillion is 3 quadrillion, not 3 quintillion. Which is their total, over a significant amount of time. The bitcoin network does over 3 quintillion (>3,000,000 trillion) hashes a second. So even if they were doing a significantly harder to compute hash -- they're still only a very small part of the computational power the bitcoin network is using. So it's probably already more effective to attack…

> So it's probably already more effective to attack wallets than join a mining pool.

That's not how you make the calculations. The reason the idea was called stupid is because the math doesn't add up. My guess is that these 3 private keys had weaknesses in them. Even the probability that they were found by "luck" is way far off.

Given merge mining is possible, I'd assume with some tweaking side-colliding + mining is possible. So if it was profitable miners would already be doing it.

Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#19

Post by always_good »

vbezhenar wrote: post #7

It seems suspicious. Bitcoin cryptography isn't broken, AFAIK, so chance to randomly break into any real wallet should be almost non-existent. I think, they either lying or exploit something different, like RNG weakness.

They're cracking a challenge with intentionally weak keys.

They're not cracking addresses generated by normal wallets.

For example, here's a challenge that gets increasingly hard that you can use to see how efficient crackers are: https://blockchain.info/tx/08389f34c98c606322740c0be6a7125d9...

Re: Large Bitcoin Collider Is Generating Trillions of Keys and Breaking into Wallets

#20

Post by domador »

If this kind of attack is feasible, then maybe one should have several wallets and spread one's Bitcoin funds among these wallets, to dilute the risk. Maybe one wallet could be used just for receiving external transactions, but its funds could be immediately transferred to other wallets. Or maybe there are also weaknesses to this approach...

I'm not currently a Bitcoin user, and ambivalent about Bitcoin's virtue, but still hope that this kind of attack turns out to be fruitless and impractical.

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