Quote from: gmaxwell on June 24, 2017, 12:18:42 AM

Yes, 2^80 is still a lot of work-- which is why I didn't just do it to make an example in a response.

But who are you to decide ...

I Ignore the language Lips sealed

Quote

... that the maximum value of of a Bitcoin exchange should be limited to under (say) $15M?

It is not about 'exchange' ... Roll Eyes

With all due respects, you are exaggerating too much.

Quote from: gmaxwell on May 01, 2017, 11:45:37 PM

I think you haven't caught the real reason that 256 bit addresses are important. Any N-bit address has only N/2 bits of security against collision, right?

Wrong! They are n/2 secure against a birthday attack in applications sensitive to birthday attack! This is it, nothing more. No generalizations please.

I appreciate your _discovery_ about vulnerabilities in bitcoin's 2-of-2 contracts and alike.

It is definitely a good hint but it has nothing to do with 'exchange' as a general concept.

Thanks to your (and other guys') posts here, one should definitively conclude that, people can 'exchange' trillions of dollars in a single bitcoin transaction and remain safe and secure but they can _not_ put multimillion dollar assets on 2-of-2 contracts in a 'naive' way.

By 'naive' I mean giving HIS right to an anonymous counter-party without using work around procedures like multiple communications proportional to the value of asset under contract.

Your points implying that people do not understand or do not follow hints, is not acceptable in this context, as we are not discussing simple low stake daily trades. Ignorant people never sign a multi million dollar contract without consultation and following the most secure procedures. In such a trade they will deliberately go through exhaustive communications that can escalate attack costs enough to de-incentivize it.

So I come to my final conclusion: Everything is OK with the current 160 bit hashed addresses and nothing will be compromised in the real world, never ever.

As I understand, you are bolding this vulnerability to justify SW once more, this time as a bonus for dealing with an attack that never gonna happen. Tongue

Am I right?