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from a51 import *
class table_gen:
def __init__(self, end_point_bit, max_chain_len, max_number_chains):
self.end_point_mask = (1 << end_point_bit) - 1
self.max_number_chains = max_number_chains
self.max_chain_len = max_chain_len
self.reduction_function = 0
def gen(self, reduction_function):
self.reduction_function = reduction_function
for chain_number in xrange(0,self.max_number_chains):
start_point = self._gen_start_point(chain_number)
(max_chain_len_exceed, end_point, chain_length) = self._gen_chain(start_point)
if max_chain_len_exceed == False: #max_chain_len_exceed is looping
print (start_point, end_point, chain_length)
def _gen_start_point(self, chain_number):
start_point = ((chain_number+1) << (18+22))+((chain_number+1) << (18))+(chain_number+1)
return start_point #TODO: find better method to generate start_points of chains
def _gen_chain(self, start_point): #a5_until_endpoint
alg = a51()
state = start_point
alg.set_state(state)
print "Generating a chain"
for chain_links in xrange(0, max_chain_len):
output = alg.gen_block(64)
print "State:%x -> Output:%x" % (state, output)
if self._is_endpoint(output):
return (False, output, chain_links)
state = self._reduction(output)
alg.set_state(state)
return (True, None, None)
def _is_endpoint(self, output):
if (output & self.end_point_mask) == 0:
return True
else:
return False
def _reduction(self, output):
return output ^ self.reduction_function
def gen_tables(max_tables, end_point_bit, max_chain_len, max_number_chains):
generator = table_gen(end_point_bit, max_chain_len, max_number_chains)
for table_nr in xrange(1,max_tables):
reduction_function = table_nr
generator.gen(reduction_function)
if __name__ == '__main__':
max_tables = 156
max_number_chains = 2000
end_point_bit = 27
max_chain_len = 2000
gen_tables(max_tables, end_point_bit, max_chain_len, max_number_chains)
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