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Topic
Board Service Announcements
Re: [ANN] Kraken Passes Cryptographically Verifiable Proof of Reserves Audit
by
Gaff
on 24/03/2014, 10:14:48 UTC
First let me just say I welcome this sort of action. It's what the community needs!

Claim 1: Kraken controls a certain amount of Bitcoins.

Proof: Kraken provided a JSON file with a list of their Bitcoin addresses and balances. I used the `cryptoshi audit` command in libcoin to verify the JSON file against a copy of the block chain.

Ok I'm probably being a noob here - but how dows this proove that Kraken actually control these bitcoins? They could have just given you a list of bitcoins that happen to be in the blockchain. Was there something signed by the private key to prove they actually control these?

*Edit:*
Just looked at the code. It has the following:

Code:
if ( addr.getPubKeyHash() == verifier.verify(address + " " + message, signature) ) {

Where message and signature are provided in the audit file, and verifier does some stuff with public keys that I can't claim to fully grasp but I will trust as being a valid cryptographic check.
 
So the implication is that Stefan provided Kraken with a message and Kraken used the private keys of the corresponding addresses to sign this message to prove Kraken had them. Would be great if this was made clearer.