Why is 6 is the number of confirmations that is considered secure? I haven’t found any mathematical explanation or otherwise that explains why it is 6 and not 5 or 7. Is there a historical reason for 6? Is there a specific way to calculate it so 6 is just a number that was chosen?
I’m trying to implement my own Markle Tree, currently I’m working on getting the hashing done correctly.
I’ve used some hashes from http://blockexplorer.com/rawblock/000000000000a85d42610b292d2baebe54ff0c854847fe3d2ca37ac7d6e46b99
Example inputs (first two hashes from blockexplorer):
Ina: 3a459eab5f0cf8394a21e04d2ed3b2beeaa59795912e20b9c680e9db74dfb18c
Inb: be38f46f0eccba72416aed715851fd07b881ffb7928b7622847314588e06a6b7
Concatenated string (H1+H2): 3a459eab5f0cf8394a21e04d2ed3b2beeaa59795912e20b9c680e9db74dfb18cbe38f46f0eccba72416aed715851fd07b881ffb7928b7622847314588e06a6b7
Hash of concatenated string:
Ans v1: b5916d6bc34bd4157aa73c3d799a6cfcef85e0659465734362d0cebb8901e93d
Final hash of concatenated string:
Ans v2: 215f8397a3090a0bc8f4a2e98609a10d55fc7b939fa1ecf9803df20b1ee089a2
Result I got:
215f8397a3090a0bc8f4a2e98609a10d55fc7b939fa1ecf9803df20b1ee089a2
Expected result:
13a3595f2610c8e4d727130daade66c772fdec4bd2463d773fd0f85c20ced32d
Checked my calculations “manually” using http://www.fileformat.info/tool/hash.htm?hex=b5916d6bc34bd4157aa73c3d799a6cfcef85e0659465734362d0cebb8901e93d
and got the same results.
Am I doing someting wrong following this example: https://en.bitcoin.it/wiki/Protocol_specification#Merkle_Trees .
I take my input hashes, concatenate them together, and double SHA256 that string. I also tried treating the input strings as a and b, that is, first double SHA256 them, and only then join them together, but the result was also wrong. Does anyone have a step-by-step example of proper hashing of the Merkle Tree?
On that date, some erratic out-of-spread trades appeared on MtGox.
The explanation given says that accounts may have been compromised by the CosbyCoin attack on bitcointalk.org. I do not understand how this can lead to out-of-spread orders being executed.
He says the issue is resolved and proceeds to give us a speech about password security and says that we should keep trading “in confidence”.
That does not satisfy me at all.
I am curious about how to acquire a lot of bitcoins (or similarly move a lot of bitcoins) without hitting the bid/ask
I don’t care about blockexplorer, I am just curious about price discovery
are there any darkpools? could I just use an illiquid exchange and personally contact the counterparty and have them take the trade
options would be good too, this would make acquiring bitcoins at a certain strike easier as this is already a negotiation between the person on the other side of the contract
Every time I turn on the Bitcoin client it takes days to catch up with the block chain.
Are there alternatives to getting it trickling through the peer-to-peer network? Can I just download it somewhere? Wouldn’t this be ideal for distribution via BitTorrent?
If so, how do I import it into the Bitcoin client?
My client would still be validating this data (can it?), and it is all signed and proof-of-worked, so there is no real security problem here, is there?
Is it possible to mine with Nvidia Quadro 600? Both GUIMiner and DiabloMiner report that no OpenCL platforms/devices were found. How can I check if GPU has OpenCL?
Bitcoin protocol supports scripts.
One of the arguments made against Bitcoin’s design choices is that it wastes resources authenticating transactions. In particular, finding small hashes is completely useless for the world.
Are there approaches (or other crypto-currencies) that use proof-of-work by working on some useful difficult problem? There are plenty of projects like SETI@home or Folding@home that distribute difficult but potentially useful calculations among different users, is there a way to use such useful calculations for building a proof-of-work system in a crypto-currency, or is there a fundamental reason (economic or computational) that a proof-of-work must involve useless work?