Quote from: nealmcb on July 07, 2011, 05:58:02 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