Use SecureRandom instead of java.util.Random.

import java.security.SecureRandom;

import java.util.ArrayList;

import java.util.List;

import java.util.Random;

/**

 * Assorted utility methods for implementing crypto operations on top of KeyStore.

abstract class KeyStoreCryptoOperationUtils {

    private static volatile SecureRandom sRng;

    private static final Random sRandom = new Random();

    private KeyStoreCryptoOperationUtils() {}

        } else {

            // Keystore won't give us an operation challenge if the operation doesn't

            // need user authorization. So we make our own.

            return sRandom.nextLong();

            return getRng().nextLong();

        }

    }

}