Topic: ASIC Mining Altcoin with 181 byte blockheader (Read 142 times)

Hello all,

I have been toying around with a Gekkoscience 2PAC with the hopes of possibly getting it to mine a SHA256 alt coin with a large block header. I am editing cgminer and so far I am not having a lot of luck. I have read on Telegram that it can't be done, which makes me want to do it. The header is as follows:

[4] - version
[32] - previous hash
[32] - merkle root
[4] - time
[4] - nbits
[4] - nonce
[32] - stateroot
[32] - utxoroot
[32] - 0's
[4] - F's (ffffffff)
[1] - 0's

Being the alt coin is based on bitcoin my theory is that instead of making the midstate from the first 64 bytes, I could get creative and do the following.
extras = sha256(stateroot + utxoroot + 0's + F's + 0's) - 32bytes ( these values also don't change)

midstate = sha256(First 64 bytes + extras)

This inherently does not crash the ASIC when it runs, but any blocks are rejected. I think it has to do with the regen_hash function that will only accept a sha256 value of 80 bytes. I have tried to make it the 181 byte value and pass in the full header but the 2PAC errors out and won't hash. I am not exactly sure why not, since sha256 should not care the size of the message. At 80 bytes it all runs.

This is a bit of a long shot, but I thought I would toss it out here in case anyone has an idea or maybe assurance that it is impossible.

Thanks,
Joe