Constructs a NaccacheSternPrivateKey
Parameters: g - the public enryption parameter g Parameters: n - the public modulus n = p*q Parameters: lowerSigmaBound - the public lower sigma bound up to which data can be encrypted Parameters: smallPrimes - the small primes, of which sigma is constructed in the rightorder Parameters: phi_n - the private modulus phi(n) = (p-1)(q-1)