Fix parameters for Naor Pinkas OT about fresco HOT 7 CLOSED

Right, but it only shows the generation from a PRG seed. It does not validate the safety as you also write. (Because they are not safe).
It is crucial to always use safe parameters, as otherwise the discrete log assumption might not be hard and the security of the entire system falls to the ground.
If the primes in this standard are safe then please use them. Even better than generating them ourselves. But please verify they are safe! The standard does not mention safe or Sophie Germain (other term for safe primes)

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For example consider adding the following test:

@Test
  public void validateParameters() {
    BigInteger subgroupSize = staticSpec.getP().subtract(BigInteger.ONE).divide(BigInteger.valueOf(2));
    assertEquals(BigInteger.ZERO,
        staticSpec.getP().subtract(BigInteger.ONE).remainder(BigInteger.valueOf(2)));
    assertTrue(subgroupSize.isProbablePrime(80));
  }

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The parameters for NoarPinkas OT seems to be defined in https://github.com/aicis/fresco/blob/87ce7366ce577f66034e7ae5db457a8d65ab3535/tools/ot/src/main/java/dk/alexandra/fresco/tools/ot/base/DhParameters.java, which is also used in ChouOrlandi based on BigIntegers (since it also used DH at its core).

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Yes, exactly. I checked the parameters and P is not a safe prime. Computing and making an automated test for validating security of the parameters, is what this task is about.

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But in this case, should we generate a random pair of p and g or should we switch over to a static safe pair, i.e. https://www.ietf.org/rfc/rfc3526.txt since finding safe primes is a slow process? In either case the static unsafe pair should be changed.

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Also, it seems like the DH parameters are tested here () actually, however it fails the sanity check for being a safe prime, as you described earlier.
https://github.com/aicis/fresco/blob/master/tools/ot/src/test/java/dk/alexandra/fresco/tools/ot/base/TestDhParameters.java

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Fixed in 2ce267e

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