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https://github.com/bitcoinbook/bitcoinbook
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63 lines
1.8 KiB
Python
Executable File
63 lines
1.8 KiB
Python
Executable File
#!/usr/bin/env python
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# example of proof-of-work algorithm
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import hashlib
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import time
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max_nonce = 2 ** 32 # 4 billion
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def proof_of_work(header, difficulty_bits):
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# calculate the difficulty target
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target = 2 ** (256-difficulty_bits)
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for nonce in xrange(max_nonce):
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hash_result = hashlib.sha256(str(header)+str(nonce)).hexdigest()
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# check if this is a valid result, below the target
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if long(hash_result, 16) < target:
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print "Success with nonce %d" % nonce
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print "Hash is %s" % hash_result
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return (hash_result,nonce)
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print "Failed after %d (max_nonce) tries" % nonce
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return nonce
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if __name__ == '__main__':
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nonce = 0
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hash_result = ''
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# difficulty from 0 to 31 bits
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for difficulty_bits in xrange(32):
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difficulty = 2 ** difficulty_bits
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print "Difficulty: %ld (%d bits)" % (difficulty, difficulty_bits)
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print "Starting search..."
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# checkpoint the current time
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start_time = time.time()
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# make a new block which includes the hash from the previous block
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# we fake a block of transactions - just a string
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new_block = 'test block with transactions' + hash_result
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# find a valid nonce for the new block
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(hash_result, nonce) = proof_of_work(new_block, difficulty_bits)
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# checkpoint how long it took to find a result
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end_time = time.time()
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elapsed_time = end_time - start_time
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print "Elapsed Time: %.4f seconds" % elapsed_time
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if elapsed_time > 0:
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# estimate the hashes per second
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hash_power = float(long(nonce)/elapsed_time)
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print "Hashing Power: %ld hashes per second" % hash_power
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