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Exmo Bitcoin exchange chief executive kidnapped in Kiev

bbc.com

41–50 of 142 posts

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#41
post #38

The Winkofloss brothers stores their codes right to prevent these type of kidnappings. They distributed the keys across states and bank vaults.

Found a source (not much more detail though) http://www.businessinsider.de/winklevoss-twins-cut-up-key-to...

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#42
post #24

I raised this concern in a comment last week. We are going to see more instances of this. Remember how in the movies they break into a bank manager's house and hold the family captive while someone goes with the manager to open the bank vault? Same thing is inevitably going to happen IRL. I always say exchangers are Bitcoins weakest link. All it takes is one compromised employee at Coinbase or another large exchanger…

2018 will be an interesting year for decentralized exchanges and atomic swaps.

2018 will be the year that a major US exchanger gets raided by the FBI/SEC.

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#43
post #35
post #21

Earlier quoted context omitted.

The mathematical basis for multisig wallets is explicitly resistant to rubber-hose cryptanalysis, if the keys are distributed sensibly (e.g. with one going off to a counter party in a different political regime who can’t be compelled by the same state-actors as you to share keys.)

The best way to not get your car stoken is to leave the engine in a warehouse in Germany, the chassis in a car park in Brazil and the rest in your garage in California. That's super secure but how do you use it every day?

An exchange doesn't have to have all of their assets ready to use at a moment's notice. They could have 95% of their assets locked up in an inconvenient but safe method. If their hot wallet starts running low, then they begin the process to top it up with their hard-to-use multisig protected funds.

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#44
post #24

I raised this concern in a comment last week. We are going to see more instances of this. Remember how in the movies they break into a bank manager's house and hold the family captive while someone goes with the manager to open the bank vault? Same thing is inevitably going to happen IRL. I always say exchangers are Bitcoins weakest link. All it takes is one compromised employee at Coinbase or another large exchanger…

How many of these kidnappings are going to be faked to provide cover for a theft? It's exactly the thing I would do.

"We've been hacked" has been a cover for exchanges stealing funds for years now.

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#45
post #32

Earlier quoted context omitted.

You could take a private key and split it into three parts and store them separately.

You should rather xor it with two other random keys.

I don't think I follow you, could you please explain what you mean a bit further?

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#46
post #29

Earlier quoted context omitted.

Or you can use the strengths of cryptocurrency and split a key between a safe deposit box, your home, and yourself, and require 2 of 3 of them to get the original key.

That definitely helps against many scenarios, but "home and yourself" means you're still in immediate control of funds while you're at home, so you're still vulnerable to armed robbery. You want to make it so your answer to the robber is "I can't, the bank's not open."

And then what? The robber who went through the trouble of breaking in and demanding your money will apologize and see himself out?

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#47

Earlier quoted context omitted.

How many of these kidnappings are going to be faked to provide cover for a theft? It's exactly the thing I would do.

"We've been hacked" has been a cover for exchanges stealing funds for years now.

Oops our servers couldn't keep up right at the point in time when this coin exploded/plumetted.

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#48
post #38

The Winkofloss brothers stores their codes right to prevent these type of kidnappings. They distributed the keys across states and bank vaults.

winklevoss? Distributing keys doesn't prevent you from having a few "digits" (no pun intended) removed. "Oh you can't get them? Call the other key-holders. Better hope they like your fingers as much as you do."

In "Casino" Robert De Niro's character puts $2M in jewels in a safe-deposit box that even he doesn't have the key for (he naively gives the key to his wife- but that's another part of the plot) He narrates that the jewels are "in case he got in trouble". Ostensibly so he could pay off kidnappers.

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#49
post #27

So it appears criminals are getting wiser and a new wave of home and personal robberies may emerge. Will this push crypto owners to entrust their currency with more secure institutions, leading to these "decentralized" currencies to be once again under control and manipulated by banks and governments?

Bitcoin was released at 2009. Since then, this is the first kidnapping probably linked to cryptocurrencies. Yeah, this is definitely a trend. Since people are publicly boasting about their crypto fortunes and kidnappers has published their demands... /s

Re: Exmo Bitcoin exchange chief executive kidnapped in Kiev

#50
post #45
post #32

Earlier quoted context omitted.

You should rather xor it with two other random keys.

I don't think I follow you, could you please explain what you mean a bit further?

You don’t really want to split the key (as in if the key is n bytes, split it in 3 segments of n/3 bytes) because if one has two segments, I imagine it’s not inconceivable to infer the third segment from the public key and the other two (though I haven’t made the math).

Rather you have a private key p of n bytes. Create two cryptographically random keys k1 and k2 of n bytes each. Derive a key k3=(p XOR k1) XOR k2. k1, k2 and k3 are your distributed keys. To recompute p you need to do p = (k3 XOR k2) XOR k1.

A XOR is trivial to implement and I would expect be reasonably robust.

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