Is the modulus fixed or unknown?

X^(2^T) mod N
I know that both X and N are 1024 bits. X will be chosen at random at test time. How will N be chosen? Will it be chosen randomly at test time or the fixed value given in

Is N prime?

Actually N cannot be a prime else the problem is trivial. Is N guaranteed semi-prime?

Hi uednva,

The modulus is fixed, and is published here:

The modulus is semiprime, that is the product of two primes.

Please let me know if you have any more questions.

To add to what was said, the factorisation of the modulus (i.e. the two prime factors, each of size about 512-bit) is unknown to contestants.