Issue with Blockheader from Stratum Data

Hey hey

I'm writing a python script to take stratum tcp messages recorded through a mining proxy to reconstruct blockheaders and verify the miners' work. Documentation seems fairly sparse and at times conflicting.

From an initial 'mining.subscribe' response, we can gather the ExtraNonce1 (or from a later 'mining.set_extranonce')

From a 'mining.notify' job specification, we can gather the version, previous hash, time, and nBits towards the blockheader, additionally we can gather both the coinbase bits and the merkle branches.

From a 'mining.submission', we can gather the extraNonce2 and the nonce.

We can build the merkle root applying the following by first constructing the coinbase_hash:

Code:

coinbase=trans1+extraNonce1+extraNonce2+trans2
coinbase_hash_bin = hashlib.sha256(hashlib.sha256(binascii.unhexlify(coinbase)).digest()).digest()

and then the following:

Code:

def build_merkle_root(merkle_branch, coinbase_hash_bin):
   merkle_root = coinbase_hash_bin
   for h in merkle_branch:
   #merkle_root = doublesha(merkle_root + binascii.unhexlify(h))
   merkle_root = hashlib.sha256(hashlib.sha256(merkle_root + binascii.unhexlify(h)).digest()).digest()
   return binascii.hexlify(merkle_root)

From here is where things seem to get fuzzy, as https://github.com/ricmoo/nightminer/ gives a different order for the blockheader than say https://braiins.com/stratum-v1/docs where ricmoo has the nbits before the ntime, whilst the latter (and most other documentation) has nbits after ntime.

I can build a simple byte reversal and swap for the merkel_root via:

Code:

def swap_order(s):
   a=list(s[::-1])
   a2=list(s[::-1])
   for i in range(0,len(s),2):
   a[i]=a2[i+1]
   a[i+1]=a2[i]
   return ''.join(a)

and get towards the following:

Code:

padding='000000800000000000000000000000000000000000000000000000000000000000000000000000000000000080020000'
blockHeader=btcVersion+prevHash+swap_order(str(mk_root,'utf-8'))+nTime+nBits+nOnce+padding
hexlify(hashlib.sha256(hashlib.sha256(binascii.unhexlify(blockHeader)).digest()).digest())

but this does not seem to result in hashes that are below the target difficulty.

I've struggled to find a straightforward version of this kind of a script and would appreciate any tips, insights, or links to related projects Huh

Topic: Issue with Blockheader from Stratum Data (Read 58 times)