Socat: “the hard coded 1024 bit DH p parameter was not prime”

Re:Socat: “the hard coded 1024 bit DH p parameter was not pr... by qwerty1793 on Monday February 01, 2016 @09:57PM (#11017411)

The following Sage script shows that p has no prime factors less than 2^32 other than 271 and 13597:

  p_list = [0xCC, 0x17, 0xF2, 0xDC, 0x96, 0xDF, 0x59, 0xA4, 0x46, 0xC5, 0x3E, 0x0E, 0xB8, 0x26, 0x55, 0x0C, 0xE3, 0x88, 0xC1, 0xCE, 0xA7, 0xBC, 0xB3, 0xBF, 0x16, 0x94, 0xD8, 0xA9, 0x45, 0xA2, 0xCE, 0xA9, 0x5B, 0x22, 0x25, 0x5F, 0x92, 0x59, 0x94, 0x1C, 0x22, 0xBF, 0xCB, 0xC8, 0xC8, 0x57, 0xCB, 0xBF, 0xBC, 0x0E, 0xE8, 0x40, 0xF9, 0x87, 0x03, 0xBF, 0x60, 0x9B, 0x08, 0xC6, 0x8E, 0x99, 0xC6, 0x05, 0xFC, 0x00, 0xD6, 0x6D, 0x90, 0xA8, 0xF5, 0xF8, 0xD3, 0x8D, 0x43, 0xC8, 0x8F, 0x7A, 0xBD, 0xBB, 0x28, 0xAC, 0x04, 0x69, 0x4A, 0x0B, 0x86, 0x73, 0x37, 0xF0, 0x6D, 0x4F, 0x04, 0xF6, 0xF5, 0xAF, 0xBF, 0xAB, 0x8E, 0xCE, 0x75, 0x53, 0x4D, 0x7F, 0x7D, 0x17, 0x78, 0x0E, 0x12, 0x46, 0x4A, 0xAF, 0x95, 0x99, 0xEF, 0xBC, 0xA6, 0xC5, 0x41, 0x77, 0x43, 0x7A, 0xB9, 0xEC, 0x8E, 0x07, 0x3C, 0x6D]

  p = 0
  for num in p_list: p = (p << 8) + num

  for i, prime in enumerate(primes(2^32)):
      if i % 100 == 0: print str(prime) + '\r',
      if p % prime == 0: print('\n')

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Re:Socat: “the hard coded 1024 bit DH p parameter was not pr... by williamstein on Tuesday February 02, 2016 @08:55AM (#11019393)

Sage also has an is_prime function, which provably show that p is not prime: "is_prime(p)". This takes less than 1ms to run. Proving primality of a 1024 bit prime in Sage takes a few seconds, and for a 2048 bit prime about a minute. Sage uses PARI for this, with sophisticated elliptic curve based algorithms called ECPP("=elliptic curve primality proving"), which are non-deterministic (unlike AKS) but fast in practice and provably correct. https://goo.gl/34uxJl

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Re:Socat: “the hard coded 1024 bit DH p parameter was not pr... by baby on Wednesday February 03, 2016 @05:13PM (#11030250)

Have you tried dividing the order by 271 and 13597 and search again on that?

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