Research on Grain Food Blockchain Traceability Information Management Model Based on Master-Slave Multichain

Algorithm 4

Improved PoW algorithm.

	Input: hash value of the previous block prehash, difficulty n;
	Output: random number nonce;
(1)	def hash (prehash, nonce);
(2)	str = f′{prehash}{nonce}′.encode()
(3)	return hashlib.sha256 (str).hexdigest ()//Generate SHA256 Summary
(4)	def proof (prehash.n):
(5)	nonce = 0
(6)	while hash (prehash.nonce) [:n] ! = str (0).zfill (n)
(7)	nonce+ = 1
(8)	return nonce