Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Here’s who probably did that $150 million Bitcoin transaction

washingtonpost.com

Post reply on HN
Print view View original

81–90 of 118 posts

Re: Here’s who probably did that $150 million Bitcoin transaction

#81

Post by baddox »

gnaritas wrote: post #16
josephagoss wrote: post #7

Earlier quoted context omitted.

Please stop with the privacy scaremongering. A lot of work is currently going into trustless mixing/anonymising services that will largely stop this type of tracking. (coinjoin/zerocoin) A lot of us are investing with the expectation true anonymous transactions eventually happen, because when they do Bitcoin will become even more valuable.

> A lot of work is currently going into trustless mixing/anonymising Call it what it is, money laundering.

It's both. There is such a thing as synonyms.

Re: Here’s who probably did that $150 million Bitcoin transaction

#82

Post by ars »

[deleted] wrote: post #80
meowface wrote: post #78

Earlier quoted context omitted.

It's completely infeasible (without quantum computers anyway). However, in cases where the private key is generated from a hash of a passphrase, like brainwallets, then it is far more feasible. There are people running bruteforcers constantly looking for private keys corresponding to brainwallet passphrases; that's their form of "mining". To test it, if you make a brainwallet with a password of "password" and then se…

[deleted]

> What about looking for keys generated using the broken Debian RNG?

You'd need a time machine, and if you had one I can think of better uses.

Actually even a time machine wouldn't help since bitcoin showed up long after the RNG was fixed.

Re: Here’s who probably did that $150 million Bitcoin transaction

#83

Post by waps »

meowface wrote: post #78
rheide wrote: post #14

I wonder if it ever becomes viable to try to brute-force the private key of such a valuable address, rather than devoting the brute force power to mining. Edit: got curious and found an answer: http://bitcoin.stackexchange.com/questions/2847/how-long-wou... If I understand correctly, it's still not viable even if you tried your brute-forced keys on all addresses in the network.

It's completely infeasible (without quantum computers anyway). However, in cases where the private key is generated from a hash of a passphrase, like brainwallets, then it is far more feasible. There are people running bruteforcers constantly looking for private keys corresponding to brainwallet passphrases; that's their form of "mining". To test it, if you make a brainwallet with a password of "password" and then se…

I don't think so. Brainwallets are generated as a hash. So if the input is secure, the output is secure. It's not possible to generate the input from the output. And frankly the connection between password -> private key and private key -> public key is very similar in brainwallets. To crack a brainwallet, given only the public key and sufficient bits in the password, is actually harder than directly attacking the private key.

Plus you have to balance "my own fuckup" risk against "someone attacked me" risk, right. Wallets depend on your backup habits, and you backup provider's security. Going through the fora, I'd say "oops. I lot my wallet.dat" is a much more serious threat to your bitcoins, on average, than someone got a hold of your password. Both of those, for most people (including me) are ... lacking. Brainwallets depend on my memory for passwords. A hardware brainwallet would guarantee you're 100% not exposed.

As for ECSDA attacks. It's true that the algorithm itself is near-unhackable. However, make one single transaction on a computer which chooses a non-random k value, and you're exposed. So the risks don't end just because

Re: Here’s who probably did that $150 million Bitcoin transaction

#84

Post by [deleted] »

ars wrote: post #82
[deleted] wrote: post #80

Earlier quoted context omitted.

[deleted]

> What about looking for keys generated using the broken Debian RNG? You'd need a time machine, and if you had one I can think of better uses. Actually even a time machine wouldn't help since bitcoin showed up long after the RNG was fixed.

[deleted]

Re: Here’s who probably did that $150 million Bitcoin transaction

#85

Post by mindcrime »

consonants wrote: post #49
fexl wrote: post #39

Earlier quoted context omitted.

The term "money laundering" originally referred to the practice of concealing the movement of funds involved in a crime. Now they've redefined it so that concealing the movement of funds is itself a crime, even if the funds are entirely legitimate and no other crime is involved.

Yes, because the motivations behind money laundering are driven almost exclusively by crime. For purchases you wish to remain private, such as personally embarrassing products, there are 'anonymizing' but traceable services for you to save face with. There are very few legitimate reasons to be concealing where you money came from or is going from the IRS, and they well aware of the intent behind the actions.

There are very few legitimate reasons to be concealing where you money came from or is going from the IRS

That's irrelevant. I don't need a reason for concealing where my money comes from.

Oh sure, the IRS may disagree, but I have a really hard time giving a shit about what the IRS thinks.

Re: Here’s who probably did that $150 million Bitcoin transaction

#86

Post by gnaritas »

VMG wrote: post #67
hbags wrote: post #29

Earlier quoted context omitted.

A mixer's sole purpose in life is collect a fee for concealing sources of money. It's textbook money laundering.

Except with Bitcoin, there are valid reasons to conceal the source and destination of money from the public besides criminal activity. The money being "laundered" isn't necessarily "dirty" to begin with. The same logic applies to encryption. People have a right to privacy.

It doesn't matter what the reasons are, or whether you have a right to it, if you're trying to conceal where money came from, it's money laundering.

Re: Here’s who probably did that $150 million Bitcoin transaction

#87

Post by Zoomla »

cpach wrote: post #22
rheide wrote: post #14

I wonder if it ever becomes viable to try to brute-force the private key of such a valuable address, rather than devoting the brute force power to mining. Edit: got curious and found an answer: http://bitcoin.stackexchange.com/questions/2847/how-long-wou... If I understand correctly, it's still not viable even if you tried your brute-forced keys on all addresses in the network.

So much easier to crack the box holding the key.

hacking people on #bitcoin, #bitcoin-otc, etc. on freenode might or might not be a good start

Re: Here’s who probably did that $150 million Bitcoin transaction

#88

Post by dllthomas »

hbz wrote: post #9

This type of "sophisticated analysis" will be useless whenever zerocoin is proven as a viable addition to the protocol. True anonymity is scary from a regulatory standpoint but extremely desirable to many others.

I would be unsurprised if use of zerocoin winds up being treated as money laundering.

Re: Here’s who probably did that $150 million Bitcoin transaction

#89

Post by asperous »

meowface wrote: post #78
rheide wrote: post #14

I wonder if it ever becomes viable to try to brute-force the private key of such a valuable address, rather than devoting the brute force power to mining. Edit: got curious and found an answer: http://bitcoin.stackexchange.com/questions/2847/how-long-wou... If I understand correctly, it's still not viable even if you tried your brute-forced keys on all addresses in the network.

It's completely infeasible (without quantum computers anyway). However, in cases where the private key is generated from a hash of a passphrase, like brainwallets, then it is far more feasible. There are people running bruteforcers constantly looking for private keys corresponding to brainwallet passphrases; that's their form of "mining". To test it, if you make a brainwallet with a password of "password" and then se…

You are right and here's why:

Brainwallet inputs -> public keys are deterministic. It's true that the method of creating the key pair is as much of a password as the password, it's easy to select the most common methods (sha-256 hashes, bitaddress.org's method, etc.)

I cracked thousands of passwords for the https://keybase.io/warp competition (I lost by a few minutes... the answer to the top one is Je).

Once you have those public, private key pairs you can simply make an index of them and watch the blockchain for any of them to show up.

Re: Here’s who probably did that $150 million Bitcoin transaction

#90

Post by maaku »

mikeash wrote: post #48
nwh wrote: post #36

Earlier quoted context omitted.

That's the entire point of asymmetric crypto, the amount of effort you would need to brute force 2^160 keys is staggering. Even if you made billions of ASIC processors and ran them until the end of time, you probably wouldn't find the funds you were looking for. This is constantly suggested, and it's always useless. If you could attack keys like this the system would be broken.

It's important to note that asymmetric crypto behaves somewhat differently. RSA is a particularly notable example of this: a 160-bit RSA key is almost trivial to break, 512-bit keys are possible, and there are good reasons to think that large organizations with lots of cash and motivation are able to break individual 1024-bit keys when they want to. The ECDSA keys used in Bitcoin are much stronger than RSA keys at th…

No. What the GP is quoting is "security bits" a measure explicitly designed to mitigate that difference. Bitcoin addresses have 160 bits of security, 128 bits if the public key is known. This is directly comparable to symmetric key sizes.
Post reply on HN