public void testRandomString() throws Exception {
   SecureRandom rng = MiscTestUtil.getSecureRandom();
   String r10 = KeyStoreUtil.randomString(10, rng);
   String r1024 = KeyStoreUtil.randomString(1024, rng);
   assertEquals(10, r10.length());
   assertEquals(1024, r1024.length());
   assertCharsBetween(32, 126, r10);
   assertCharsBetween(32, 126, r1024);
   assertNotEquals(r1024, KeyStoreUtil.randomString(1024, rng));
 }
  public void testCreateSharedPLNKeyStores() throws Exception {
    List<String> hosts = ListUtil.list("host1", "host2.foo.bar", "host3");
    List<String> hosts2 = ListUtil.list("host3", "host4");
    File dir = getTempDir();
    File pub = new File(dir, "pub.ks");
    KeyStoreUtil.createSharedPLNKeyStores(
        dir, hosts, pub, "pubpass", MiscTestUtil.getSecureRandom());
    assertPubKs(pub, "pubpass", hosts);
    for (String host : hosts) {
      assertPrivateKs(
          new File(dir, host + ".jceks"), StringUtil.fromFile(new File(dir, host + ".pass")), host);
    }
    KeyStore pubks1 = loadKeyStore("jceks", new File(dir, "pub.ks"), "pubpass");

    Certificate host1cert1 = pubks1.getCertificate("host1.crt");
    Certificate host3cert1 = pubks1.getCertificate("host3.crt");

    String host1priv1 = StringUtil.fromFile(new File(dir, "host1.jceks"));
    String host3priv1 = StringUtil.fromFile(new File(dir, "host3.jceks"));

    // Now add host4 and generate a new key for host3
    KeyStoreUtil.createSharedPLNKeyStores(
        dir, hosts2, pub, "pubpass", MiscTestUtil.getSecureRandom());
    List<String> both = ListUtils.sum(hosts, hosts2);
    assertPubKs(pub, "pubpass", both);
    for (String host : both) {
      assertPrivateKs(
          new File(dir, host + ".jceks"), StringUtil.fromFile(new File(dir, host + ".pass")), host);
    }
    KeyStore pubks2 = loadKeyStore("jceks", new File(dir, "pub.ks"), "pubpass");
    // host1 should have the same cert, host3 not
    Certificate host1cert2 = pubks2.getCertificate("host1.crt");
    Certificate host3cert2 = pubks2.getCertificate("host3.crt");
    assertEquals(host1cert1, host1cert2);
    assertNotEquals(host3cert1, host3cert2);

    // host1's private key file should be the same, host3's not
    String host1priv2 = StringUtil.fromFile(new File(dir, "host1.jceks"));
    String host3priv2 = StringUtil.fromFile(new File(dir, "host3.jceks"));
    assertEquals(host1priv1, host1priv2);
    assertNotEquals(host3priv1, host3priv2);
  }