The answer is 00000000000000001e8...

nealmcb

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Quote from: imperi on July 07, 2011, 01:26:19 PM

Quote from: nealmcb on July 07, 2011, 01:16:28 PM

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.

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

Jack of Diamonds

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Quote from: J.P. Larocque on July 13, 2011, 04:31:03 PM

Quote from: Jack of Diamonds on July 13, 2011, 03:25:48 PM

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

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

J.P. Larocque

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Quote from: Jack of Diamonds on July 13, 2011, 03:25:48 PM

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

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.

J.P. Larocque

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Quote from: nealmcb on July 13, 2011, 01:08:08 PM

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

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

Jack of Diamonds

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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

flailing Junk

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Quote from: Jack of Diamonds on July 13, 2011, 01:55:39 PM

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.

Jack of Diamonds

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Quote from: imperi on July 07, 2011, 01:26:19 PM

Quote from: nealmcb on July 07, 2011, 01:16:28 PM

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.

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.

nealmcb

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Quote from: nealmcb on July 07, 2011, 12:58:02 PM

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.

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:

Code:

0100000081cd02ab7e569e8bcd9317e2
fe99f2de44d49ab2b8851ba4a3080000
00000000e320b6c2fffc8d750423db8b
1eb942ae710e951ed797f7affc8892b0
f1fc122bc7f5d74df2b9441a42a14695

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

nealmcb

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Quote from: imperi on July 07, 2011, 01:26:19 PM

Quote from: nealmcb on July 07, 2011, 01:16:28 PM

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.

imperi

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Quote from: nealmcb on July 07, 2011, 01:16:28 PM

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.

nealmcb

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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

nealmcb

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Quote from: just_someguy on July 07, 2011, 12:37:12 PM

The lowest hash hit?

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.

enmaku

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

joepie91

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Quote from: 1MLyg5WVFSMifFjkrZiyGW2nw on July 07, 2011, 12:39:16 PM

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

Last time I saw so many seemingly random characters on one line was when I did cat /dev/urandom.

SgtSpike

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Current difficulty?

1MLyg5WVFSMifFjkrZiyGW2nw

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

joepie91

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Quote from: stic.man on July 07, 2011, 12:34:44 PM

thread title is fucking up my scroll dawg

Buy a wider screen.

just_someguy

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The lowest hash hit?

stic.man

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thread title is fucking up my scroll dawg

joepie91

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Topic: The answer is 00000000000000001e8... (Read 3641 times)