.net RNGCryptoServiceProvider 对应 java SecureRandom
public class SecureRandomextends Random
This class provides a cryptographically strong random number generator (RNG). Many implementations are in the form of a pseudo-random number generator (PRNG), which means they use a deterministic algorithm to produce a pseudo-random sequence from a true random seed. Other implementations may produce true random numbers and yet others may use a combination of both techniques.
http://docs.oracle.com/javase/1.5.0/docs/api/java/security/SecureRandom.html
