Question

On Linux I am used to using mkpasswd to generate random passwords to use, on OS X however I don’t have this command. Instead of sshing in to my vps every time, I wanted to re implement it using Java. What I have done is pick at random 4 lower case letters, 2 upper case letters, 2 symbols (/ . , etc) and 2 numbers. Then I create a vector and shuffle that too.

Do you think this is good enough randomization?

Answer 1

yes, it is. If you are using java.util.Random:

An instance of this class is used to generate a stream of pseudorandom numbers. The class uses a 48-bit seed, which is modified using a linear congruential formula. (See Donald Knuth, The Art of Computer Programming, Volume 2, Section 3.2.1.)

The algorithms implemented by class Random use a protected utility method that on each invocation can supply up to 32 pseudorandomly generated bits.

EDIT

in response to a comment:

/**
 * Creates a new random number generator. This constructor sets
 * the seed of the random number generator to a value very likely
 * to be distinct from any other invocation of this constructor.
 */
public Random() { 
    this(++seedUniquifier + System.nanoTime()); 
}

private static volatile long seedUniquifier = 8682522807148012L;