Great work guys, congratulations.

I'm afraid one piece of the puzzle seems still open to me. The audit proves that everyone's balance is represented in the Merkle tree, but not that the same bitcoins aren't backing two people's accounts at the same time. That is, there's no way to check against the following scenario:

USER1 audit page:
Submission code: 379377cd8190f9bf
Amount: 0.01500000

USER2 audit page:
Submission code: 379377cd8190f9bf
Amount: 0.01500000

Thankfully, this proof gap can be resolved without an auditor, and in an anonymous way.

I propose the following three-step scheme. (step 1) Kraken generates a 64-bit nonce for each account in the system. They publish this nonce on each user's account page, as follows:

USER1 audit:
Submission code: 379377cd8190f9bf
Nonce: fa132f44d7e35e0f
Amount: 0.01500000

(step 2) Kraken publish a signed document with the anonymized account name for each submission code:

$submission_code: sha256($nonce || ":" || $username)

For USER1 in our example, sha256("fa132f44d7e35e0f:USER1")=b7000194f1327aeb9b16f6104333fc889dd2f4c3cdba1eb3500d91ca5efc8208, so the document would contain:

379377cd8190f9bf: b7000194f1327aeb9b16f6104333fc889dd2f4c3cdba1eb3500d91ca5efc8208

(step 3) Users will verify not only that their submission code exists in the Merkle tree, but also that the submission code cannot correspond to any other account by calculating the sha256 as above and verifying that it corresponds to the submission code.

(end of scheme)

The only drawback I see is that this will make public the number of accounts in the Merkle tree, but I don't think this should be a problem.

Let me know what you think.

Could you enable Apps2SD? When I install it on my HTC Desire, it says I don't have enough space available.

Could be useful, but the delay between them asking and you seeing the question would probably take most of the fun out of it. But it could still be useful/handy for a limited number of things.

What would be your rate per hour/search?

By the way, do you know Mechanical Turk?

This would kill international Bitcoin trade. The Vietnamese would never use it, for instance, if it finances Uncle Sam's peace operations.

@fadisaaida: The attributes in the HTML seem to be swapped:


I claim http://myB.TC/bgeron (code=78142).

Edit: my registration passed! Strange.

We only need 5 more on-topic questions and 5 more off-topic questions. Please vote for new questions and submit new questions!

I just posted 2 questions.

What about one of these?





I prefer the first.

Small examples:

3.45

3.45