Python Program to Create a Proof of Work Generator Assignment Solution.

POW CHECK

import sys

import hashlib

def hash(bytes):

hex = hashlib.sha256(bytes).hexdigest()

return hex

def get_leading_zeros(hex):

# Take each element of the hex and convert to binary

bin_str = hex_to_bin(hex)

# Convert to binary

# Get the first n_leading bits

# Count until there is no leading zero

counter = 0

for c in bin_str:

if c == '0':

counter += 1

else:

break

return counter

def hex_to_bin(hex):

bin_str = ""

hex_int = int('1'+hex, 16)

c_bin = bin(hex_int)[3:].zfill(4)

bin_str = str(c_bin)

# for c in hex:

# c_int = int(c, 16)

# c_bin = bin(c_int)[2:].zfill(4)

# bin_str += str(c_bin)

return bin_str

if __name__ == '__main__':

# Variable to ccount the number of tests passed

tests_passed = 0

# Get file from command line arguments

if len(sys.argv) < 3:

print("You must give a filename and the number of leading zeros.")

sys.exit(0)

powheader = sys.argv[1]

file = sys.argv[2]

# First, read the hex in the file

f = open(file, 'rb')

bytes = f.read()

initial_hash = hash(bytes)

# Now open the headerfile

header = open(powheader, 'r')

# Read lines

lines = header.readlines()

# The initial hash is in the second file (index 1)

header_initial_hash = lines[1].strip().split(' ')[1]

# The hash is in the 3rd line

header_hash = lines[3].strip().split(' ')[1]

# Get reported number of leading zeros

zeros_reported = int(lines[4].strip().split(' ')[1])

# Get proof of work

reported_pow = lines[2].strip().split(' ')[1]

# Check that initial hashes are the same

if header_initial_hash == initial_hash:

print("PASSED:", "initial file hashes match")

tests_passed += 1

else:

print("ERROR:", "initial hashes don't match")

print("\thash in header:", header_initial_hash)

print("\tfile hash:", initial_hash)

# Check the number of leading bits

# Take the original content of the file and append the new pow

file_text = bytes.decode('utf-8') + reported_pow

new_bytes = file_text.encode('utf-8')

new_hash = hash(new_bytes)

new_hash_bin = hex_to_bin(new_hash)

# Compute number of leading zeros

zeros = get_leading_zeros(new_hash_bin)

if zeros == zeros_reported:

print("PASSED:","leading bits is correct")

tests_passed += 1

else:

print("ERROR:",f"Leading zero-bits value: {zeros_reported} but hash has {zeros} leading zero bits")

# Now, check for final hash

if new_hash == header_hash:

print("PASSED:", "pow hash matches Hash header")

tests_passed += 1

else:

print("ERROR:", "pow hash does not match Hash header")

print("\texpected:", new_hash)

print("\tfile hash:", header_hash)

if tests_passed == 3:

print("pass")

else:

print("fail")

POW CREATE

import hashlib

import itertools

import string

import time

import sys

def hex_to_bin(hex):

bin_str = ""

hex_int = int('1'+hex, 16)

c_bin = bin(hex_int)[3:].zfill(4)

bin_str = str(c_bin)

# for c in hex:

# c_int = int(c, 16)

# c_bin = bin(c_int)[2:].zfill(4)

# bin_str += str(c_bin)

return bin_str

def hash(bytes):

hex = hashlib.sha256(bytes).hexdigest()

return hex

def iter_all_strings(count):

# Get all chars

charIds = range(33, 126+1) # ascii values for all characters

ascii_chars = [chr(id) for id in charIds if id != 34]

for s in itertools.product(ascii_chars, repeat=count):

yield "".join(s)

def pow_text(hex, text, n_leading):

#hex = hash(text)

# Take the first n_leading

charIds = range(33, 126+1) # ascii values for all characters

current = ''

n = n_leading//4-1

if n < 1:

n = 1

iters = 1

F = ""

found = False

while not found:

# Get all combinations of chars of length 'n'. Append each one to the string and check hash

for s in iter_all_strings(n):

F = s

new_text = text + s

# Get hash

bytes =new_text.encode('utf-8')

hex = hash(bytes)

# Take each element of the hex and convert to binary

bin_str = hex_to_bin(hex)

# Convert to binary

# Get the first n_leading bits

leading_bits = bin_str[:n_leading]

leading_zeros = get_leading_zeros(hex)

#if leading_bits == '0'*n_leading:

if leading_zeros >= n_leading:

found = True

break

iters = iters + 1

n = n + 1

return F, iters

def get_leading_zeros(hex):

# Take each element of the hex and convert to binary

bin_str = hex_to_bin(hex)

# Convert to binary

# Get the first n_leading bits

# Count until there is no leading zero

counter = 0

for c in bin_str:

if c == '0':

counter += 1

else:

break

return counter

if __name__ == '__main__':

# Get file from command line arguments

if len(sys.argv) < 3:

print("You must give a filename and the number of leading zeros.")

sys.exit(0)

n_leading = int(sys.argv[1])

filename = sys.argv[2]

file = open(filename, 'rb')

bytes = file.read()

text = bytes.decode('utf-8')

initial_hash = hash(bytes)

start_time = time.time()

pow, iters = pow_text(initial_hash, text, n_leading)

end_time = time.time()

new_text = text + pow

bytes = new_text.encode('utf-8')

final_hash = hash(bytes)

print("File:", filename)

print("Initial-hash:", initial_hash)

print("Proof-of-work:", pow)

print("Hash:", final_hash)

print("Leading-zero-bits:", get_leading_zeros(final_hash))

print("Iterations:", iters)

print("Compute-time:", end_time-start_time)

# text = 'The grass is green'

# start_time = time.time()

# F, iters = pow_text(text, 31)

# end_time = time.time()

# print(F, iters)

# print("Execution time: {:.2f} (s)".format(end_time-start_time))