I was going through the blockchain mining process, I understand that the nonce serves as a crucial element in the block header used to identify blocks.
The nonce does not identify the block.
Noted
The purpose of the nonce is to be an inexpensive way to change the block hash. Once everything else in the block is set up, the miner will quickly hash the block header with all of the 4 billion possible nonce values until a valid hash is found. If a valid hash is not found, the miner will make a change to the block and try again. The same thing is done in a limited way with the timestamp.
In a bid to understand this better I went back to see how this is been implemented in real sense. Writing a simple script expanded on this. My take home from your explanation is that the nonce provides a means to alter the block hash efficiently. That means if a miner needs to find a hash that starts with "0000". The hash function processes the block header, and the miner starts with a nonce of 0. And assuming they get a hash like a1b2c3... that doesn’t meet the requirement. Incrementing the nonce to 1 might yield a different hash, and they continue this process until they find the solution, say, 0000abcd....
I wanted to have a feel of this so I had to research on how it works in real sense and writing a simple script expanded the concept better. I wrote two functions one to attempt a fake mining process and another to create a block header
def mine_block(data, difficulty):
# The nonce started with an initial value of 0
nonce = 0
prefix = '0' * difficulty
#running a loop that generates the block, block_hash and also ensures the block hash starts with the expected prefix which in my case is '0'
while True:
block = f'{data}{nonce}'.encode()
block_hash = hashlib.sha256(block).hexdigest()
if block_hash.startswith(prefix):
return nonce, block_hash
nonce +=1
I used a difficulty of 4 and when i called my function it generated this nonce
45401 and a hash of
00004e3e53c08848a83a6d0f1d4612bcd7b62c2578c5e0f21f8e38c196000b76. this just defines how hard it is to find a hash that meets the criteria
data = 'Bitcoin Block Data'
difficulty = 4
print(f"Mining a block with difficulty {difficulty}...")
nonce, block_hash = mine_block(data, difficulty)
print('Block mined! Nonce:- %s Hash:=- %s' %(nonce, block_hash))
I proceeded to finding the block header which lead to writing the second function that adds the
The version, the previous hash, the markle root, timestamp, bits and the nonce.def create_block_header(version, prev_hash, markle_root, timestamp, bits, nonce):
return f'{version}{prev_hash}{markle_root}{timestamp}{bits}{nonce}'
It is making more sense to me now.
version = '00000001'
prev_hash = '0000000000000000000e1f1c8b70d60e1b6b021c6e2f0f6c1c9b8b77b2b1d1db' # Previous block hash
merkle_root = '4c6c3d8d60a1c7b1f1b2f4c3b3e1e1f4f4c3b3b1b2b2c7b11c1c7b2d3c4d5e6' # Merkle root hash
timestamp = str(int(time.time())) # Current time
bits = '17048edf' # Difficulty target
# Construct the block header
block_header = create_block_header(version, prev_hash, merkle_root, timestamp, bits, nonce) # Calculate the hash of the block header
print(f"Block Header: {block_header}")
..
I am still learning and still open to more corrections
