Creating a fake Spycoin chain

construct.py

#!/bin/python
import hashlib
import struct
import itertools

#functions from original file


def verify_block(hash, block_num):
	# Difficulty history:
	# We increased difficulty starting from block 52, have to match "Spy".
	# We increased difficulty starting from block 138, have to match "SpyCoinXoXo".

	if block_num < 52:
		return hash.startswith("Sp")

	if block_num < 138:
	  return hash.startswith("Spy")

	return hash.startswith("SpyCoinXoXo")

def block_hash(block):
   step1 = hashlib.md5(block).digest()
   step2 = hashlib.md5(step1).digest()
   return step2

def find_bytes(block, block_num):
	found = None
	#print block_hash(tr)
	for k in range(1,10):
		if found is not None:
			break
		print 'Testing ',k
		for i in itertools.product(range(255), repeat=k):
			b = block + (''.join(map(chr,i)))
			h = block_hash(b)
			if verify_block(h, block_num):
				found = (''.join(map(chr,i)),h)
				break
	return found
#construct new spycoin block

current = open('current_blockchain','rb').read()
current = bytearray(current)

newone = current[0:0x64+1]

def add_funds(src, amount):
	secret = struct.pack("8s","Secret20")
	#add transffers
	transfer = bytearray()
	transfer.append(0x03) #type
	transfer += src.decode('hex') #from
	transfer += secret #to
	transfer += struct.pack("I", amount) #amount
	return transfer

tr = bytearray()
tr += add_funds("626973686f700000", 98830)
tr += add_funds("6b61790000000000", 91400)
tr += add_funds("627269736f747700", 142487)
tr += add_funds("6167656e74393900", 90210)
tr += add_funds("646f6e706564726f", 45032)
tr += add_funds("6e61746173686100", 500000-98830-91400-142487-90210-45032)

block_num = 1
#print block_hash(tr)
confirm = current[0x65:0x65+0x12]

found = find_bytes(confirm[1:]+tr, block_num)
block_num += 1

#print 'Found: ',found
tr += found[0]
confirm[0] = 0x11+len(tr)

hash = found[1]
newone += confirm
newone += tr

while len(newone) < len(current):
	print 'Newone size: ',len(newone), 'Current: ', len(current)
	filler = bytearray()
	filler += '\xff' #size
	filler += '\x02'+hash
	filler += '\x00'
	filler += '\xff'*230
	found = find_bytes(filler[1:], block_num)
	filler += found[0]
	filler[0] = len(filler)-1
	block_num += 1
	hash = found[1]
	newone += filler

open('new_one','wb').write(newone)