Bitcoin Forum

I did some digging and came up with this distinguished number:
 00000000000000001e8d6829a8a21adc5d38d0a473b144b6765798e61f98bd1d

That's the Jeopardy answer.  Just for fun, I'll let you figure out the question.

Are you schizophrenic or something?

The question is what is the next block ?


^ this make me lol'ed a lot

I'll bite.

What is Block 125552?

You'll have to find a much more distinguishing characteristic than what a simple google will tell you.

That requires me to use my brain.  Not fun!

thread title is fucking up my scroll dawg

The lowest hash hit?

Buy a wider screen.

What is the answer to Life, the Universe and Everything?

Current difficulty?

http://img.owely.com/screens/19266/original_owely20110707-30094-1gq1n09-0.?1310060430
Last time I saw so many seemingly random characters on one line was when I did cat /dev/urandom.

~100x the number of satoshis that will ever be mined?

Ding ding ding - you are a winner!

Though I also speculate that it is the largest number of leading zeros for the hash of any known input.

Here is a list of the top 10 hashes to date, followed by the block number in which they appear.  It is based on the "hashPrev" values of a recent blockchain.  And of course, the first is the made-up value from the genesis block.

[('0000000000000000000000000000000000000000000000000000000000000000', -1),
 ('00000000000000001e8d6829a8a21adc5d38d0a473b144b6765798e61f98bd1d', 125552),
 ('0000000000000000629981ebad88aafb5856e6663998d1083d74008be66a384a', 133316),
 ('00000000000000011ac23090a91a9297e8cb27c6d81cea9fc429fd37468d509e', 128456),
 ('000000000000000166b3b12f3e8928897fa5241985e75a9d31945dc2d22a39c8', 130557),
 ('0000000000000001e4646f3b4841707b62ecf7412ebc0bdbd2538e745d474a79', 133047),
 ('0000000000000001f2542ad9420bb538ffebd2e872d1dcbed233d07dc5eb0e01', 132103),
 ('00000000000000022d118b8a6b54cf261f3fb854b32f57d70545ad566e4adc7f', 132750),
 ('0000000000000002739d5a374b95e8bd7f5b7c810d07407924385b2181586dc6', 131384),
 ('0000000000000002ed549896e4571ab6ec7d805741038cb8dac97d4c2917c729', 128687)]

Followup question: what is the exact input for this hash?  I guess it would be best to provide it as an easy-to-copy-paste value, i.e. in some standard encoding like base64, so it is easy for folks outside of the bitcoin community to validate it.

One more tidbit: here are the winners over time, with their block height.


000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f 0
000000000009606d829b157912edb060c406b519fb2bfcc1078c196b69c67e49 1430
00000000000243ab3dd422f82638c9651cfc401ac763b2228f00f6abae334f48 11686
000000000000c09b5844620bdec4d533107844efea128a6ec6326dd92f6dc7e6 43011
000000000000b545d467b95ad844b8c718f9b76e9426e4efab7e097ca09a83da 55593
0000000000009f9f9991befc49dc787a190206d1dd32467b687e32157d48c651 60040
000000000000177131355902f9a7a9d94d1f57aba9ef4430bb01123190325977 61068
000000000000013af45c4ac4814ab12a69a6e65a40db0e1e3844fcb2ecaddb24 73373
0000000000000062864d8512b92b2f6a0c2a9edcda82aae03063879b3869d507 89665
000000000000004fa1186f88c245f89757b74b7ef1fa87302ab340b635686c1c 91940
000000000000000834e72c05564b54cc21ac27fb0cbe4ec686bfe607273ad611 101777
0000000000000006acb7899a26faa6290030e25ae41c8b3f62d69809994b89d8 114335
00000000000000001e8d6829a8a21adc5d38d0a473b144b6765798e61f98bd1d 125552

So is this the equivalent of brute forcing a 64 bit password?

edit:

I mean a password that is 64 bits long, encrypted with SHA-256.

Well, 67 bits.  I'd say that if a password hash algorithm produced exactly 67 bits (i.e. sha256(sha256(input)), truncated after the 67th bit), we have to date demonstrated a crack of a particular value (all zeros).

Or, we've done something that requires 2^68 work (2^67 * 2 hashes per attempt).

I'd also like to know the cumulative number of sha256 hashes done to date by bitcoin miners, which should be on the same order of magnitude.

I wrestled through the non-standard use of little-endian hashes and input values in bitcoin, and dug out the block input which results in this tiny tiny hash output.  I documented it all as an example in the wiki:

  https://en.bitcoin.it/wiki/Block_hashing_algorithm

Here it is in hex:


Note that you have to convert it to binary, hash it with SHA-256 twice, then reverse the bytes to get the value you compare with the target.  Then convert back to hex to match the blockexplorer representation of the hash:

 00000000000000001e8d6829a8a21adc5d38d0a473b144b6765798e61f98bd1d

More than that, as explained above it equals roughly 67 bits.

Then again, do remember the BTC network has GPU power equaling 146 petaFLOPS (146,407 gigaFLOPS) average as of July 2011. That's over a hundred times faster than the Tianhe-1 supercluster that held the #1 position on the top500.org list of the world's most powerful computers.

Well not exactly. Bitcoin does not actually do floating point calculations so the FLOPS value must be some kind of estimate. If your source is bitcoin watch then I cant find any confirmation of the number or even how it is calculated. So it is remarkable if true but needs to be taken with a grain of salt I think.

I am very interested in any type of confirmation or methodology for calculating the power of the bitcoin network in floating point, integer calculations or whatever.

For example a Radeon 6990 has 5.2 gigaFLOPS of computing power[1] and yields roughly 800 megahash/s in bitcoin mining.

[1]Sources:
http://www.asus.com/Graphics_Cards/AMD_Series/EAH69903DI4S4GD5/
http://www.pcmag.com/article2/0,2817,2381557,00.asp

Kudos, this answered a few nagging questions I had with the mining process.

Apples to oranges.  If all Bitcoin miners everywhere used Radeon 6990s, then you could say that the mining collective could compute at (big number)FLOP/s if they directed their computational capacity at floating-point problems, but right now we're computing at 0 FLOP/s, simply because it's all integer based.  You can't exchange floating-point and integer operations like that.

And the Tianhe-1 is computing at 0 khash/s because it only does floating point operations. That doesn't mean it can't be utilized to mine at 1,433,600 mhash/s. (7168 Nvidia Tesla S1070 GPUs at 200 mhash/s each)
Of course it's theoretical, why would anyone assume otherwise

This is actually quite a different thing - it is finding a password which would hash to the same value, if the output of the hash was only 64 bits (really 67, FWIW).

If the password hashing algorithm was really awful, without salt or iterations (i.e. worse than what we had in 1978), these might require similar amounts of effort.  But a modern hashing algorithm like PBKDF2 or bcrypt or scrypt would make things much much harder.

See more on how password hashing should really be done at How to securely hash passwords? - IT Security - Stack Exchange (http://security.stackexchange.com/questions/211/453)