PBKDF2.this

this(MACFactory prfFactory, size_t iterations)

Constructs a PBKDF2 instance.

`prfFactory`	A delegate that creates a MAC instance (PRF) for a given key. Example: `(key) => new HMAC(new SHA1Digest(), key)`
`iterations`	The number of iterations to perform. Must be at least 1 (RFC 2898 section 5.2, step 1).

CryptoException if iterations is zero.