tjctf-breaker.py

#!/usr/bin/python

import libnum

f = open("in.txt","r")
data = f.readlines()
data_clustered = [(int(data[x].rstrip().lstrip("n = ")),int(data[x+1].rstrip().lstrip("e = ")),int(data[x+2].rstrip().lstrip("c = "))) for x in range(0,len(data),3)]
pubkeys = []
for (n,e,c) in data_clustered:
  pubkeys.append(n)
  # x = libnum.factorize(int(n))
  # print x

out = ""
print "starting factorisation with %d keys" % len(pubkeys)
for (n,e,c) in data_clustered:
  for n2 in pubkeys:
    if n != n2:
      p = libnum.gcd(n,n2)
      if p == 0 or p == 1:
        continue
      q = n/p
      thetans = (p-1)*(q-1)
      d = libnum.invmod(e,thetans)
      m = pow(c,d,n)
      out += libnum.n2s(m)
      break

f.close()

print out