password : Java Glossary

Selecting Passwords

A tool can crack your password just by trying all words in the dictionary. So you must disguise them. Add digits, mix the case. This little program will generate you an impossible to guess password. If want to make sure I am not keeping a copy, download the source, check the program out, and run it on your own machine.

• Make sure you paste the generated passwords somewhere for safekeeping. Doing this also helps verify the value you are pasting blind into web forms.
• The Australian government recommends changing passwords frequently, at least twice a year, to prevent identity theft, and using unguessable passwords at least 8 characters long with a mixture of digits and both upper and lower case letters. The password generator defaults to 10 characters. The Australians celebrate a special day in early June to change their passwords.
• Don’t use the same password at multiple sites unless you don’t care at all about the security of any of them.
• A word in the dictionary can be cracked in under a second. That is no security at all.

If, Password, the above Password Generator Java Applet does not work…

1. If Copy/Paste (Ctrl-C/Ctrl-V) do not work, you can turn them back on by modifying your java.policy file. This is not for the novice or faint of heart. instructions Your alternative is to download this program and run it without a browser.
2. Often problems can be fixed simply by clicking the reload button on your browser.
3. Make sure you have both JavaScript and Java enabled in your browser.
4. This Java Applet needs 32-bit (not 64-bit) Java 1.3 or later. For best results use the latest 1.7.0_04. If you have both 32 and 64-bit JVMs installed, in the Java Control Panel, configure your 32-bit java.exe as the user JVM and your 64-bit java.exe as the system JVM. You also need a recent browser.
5. It works under any operating system that supports Java e.g. W2K/XP/W2003/Vista/W7-32/W7-64/Linux/Ubuntu/Solaris/OSX
6. You should see the Applet above looking much like this screenshot. If you don’t, the following hints should help you get it working:
7. Especially if this Applet has worked before, try clearing the browser cache and rebooting.
8. To ensure your Java is up to date, check with Wassup. First, download it and run it as an application independent of your browser, then run it online as an Applet to add the complication of your browser.
9. If the above Applet does not work, check the Java console for error messages.
10. If the above Applet does not work, you might have better luck with the downloadable version available below.
11. If you are using Mac OS X and would like an improved Look and Feel, download the QuaQua look & feel from randelshofer.ch/quaqua. UnZip the contained quaqua.jar and install it in ~/Library/Java/Extensions or one of the other ext dirs.
12. If you are using Microsoft Internet Explorer 7, 8 or 9, try another browser. Seriously. Microsoft has taken great pains, over and over, to screw up Java and every other multi-platform standardisation.
13. If you are using Microsoft Internet Explorer 7, 8 or 9, you must click to allow blocked content permission for Active X to run. This also gives permission to Java to run. Click the Information bar, and then click Allow blocked content. Unfortunately, this also allows dangerous ActiveX code to run. However, you must do this in order to get access to perfectly-safe Java Applets running in a sandbox. This is part of Microsoft’s war on Java. Don’t put up with it! Use a different browser.
14. If you are using Microsoft Internet Explorer 9, makes sure the Java Plug-In SSV helper add-in is installed and enabled. If it is not, try reinstalling the Java JRE.
15. If you have Windows 7 64-bit and Internet Explorer 64-bit, in theory you can use 64-bit Java, but I never been able to get it to work.
16. Try upgrading to a more recent version of your browser, or try a different browser e.g. Firefox, SeaMonkey, Safari or Avant.
17. If you still can’t get the program working click HELP for more detail.
18. If you can’t get the above Applet working after trying the advice above and from the HELP button below, have bugs to report or ideas to improve the program or its documentation, please send me an email at.

   Get New Java  Get New Browser  

If the print is too small to see, use the Opera browser and zoom. Or copy/paste the generated password blind.

Implementing Passwords

In a highly secure system, each end has a public and private key. They each encrypt and digitally sign a random message for the other to establish identity. Even these have to be carefully designed to withstand a man-in-the-middle attack.

There are some lower tech alternatives:

• If you have Java on both ends, the server could send a random string of bytes to the client. The client could concatenate that with a string of bytes representing the password, then run it through a SHA-1 (Secure Hash Algorithm 1) or MD5 (Message Digest algorithm 5) digest and send it back to the server. The server does the same thing and compares its version with the client’s.
• If the server is C++ it won’t necessarily have access to a SHA-1 or MD5 digest. You could then have to come up with a digest function you can implement easily in C++. You could use an Adler or CRC (Cyclic Redundancy Check) with some wrinkle to make it a tad harder to crack, or use one of the HashCode algorithms.
• If you want to avoid a two way exchange for faster login, let the random key be the time of day stamp in UTC (Coordinated Universal Time/Temps Universel Coordonné). The client sends it along in plaintext with the digest. The timestamp is rejected if it is too far from "now".
• For something even lower tech, but unfortunately easy to crack, try XORing the bytes of the password with something you change periodically.
• Base64 alone, cascaded Base64 or ROT13 is no protection at all.

Digest Passwords

Typically raw binary bytes generated by such authentication schemes are exchanged in base64.

Tomcat has a single signon so that all applications in a realm share the same set of user-ids and passwords. If a user logs into one application, he is logged into all. This scheme uses cookies to authenticate each request.

Tomcat lets you configure the tables and columns to automatically look up and validate passwords. Caucho Resin similarly lets you configure SQL (Standard Query Language) queries to automatically find the passwords in your database.

Graphical Passwords

Passwords at the Client

Passwords at the Server

Java Servlets defines a simple password scheme controlled entirely by a flat file web.xml. This would be suitable for a small company where the list of users and passwords could be maintained with a text editor by the system administrator.

The best approach (for expandability) is to incorporate a third party SSO (Single Sign-On) (some application servers come with one). This allows you to add new applications and share the login across them with a minimum of effort. Also, they typically plug into an existing LDAP (Lightweight Directory Access Protocol) taking user and password management out of the application’s hands. This allows corporations to take advantage of existing LDAP data when deploying applications.

Tomcat offers five different interfaces to databases of passwords. JDBC (Java Data Base Connectivity) Realm lets you interface to a SQL users and userroles tables. You configure the name of your table containing the user ids and passwords (among other things) and your roles table which describes which roles a user can play. You assign Tomcat a userid/password and jDBC connect string to give it with read-only access to your database to perform the authentications. It is much simpler than it first looks.

Puzzles

• How do you arrange for a timeout, so that after a period of inactivity, the login expires and the user has to re-enter his password. I know how to do it from first principles, but not with Tomcat.
• Just how much does the Applet get in involved with cookies, or do they get piggybacked behind its back.
• Does Java Authenticator understand the Tomcat cookie scheme?

Diceware

This is a scheme for picking a password without using a computer, just some casino dice. The paranoid instructions are somewhat tongue in cheek. The scheme is just as vulnerable as any other if there is a keystroke logger (hardware or software) installed on your computer. It is just as vulnerable as other schemes to others discovering a copy of your password stored somewhere. The big advantage is you don’t have to trust the author of password-generating software.