Submitted by vgarramone on Sun, 05/23/2010 - 13:04
This applet demonstrates the RC4 stream cipher, which is used in many applications, including the SSL that protects secure web pages (HTTPS). Includes suggested exercise and explanatory text.
Submitted by vgarramone on Sun, 05/23/2010 - 13:01
In RC4, the first 256 steps use the key to perform a transposition on an array of the bytes from 0 to 255. Ideally, a random key should result in a random distribution. However, the resulting distribution is far from random. This applet is running RC4 many times with different, random, 16-byte keys, and gives various statistics of transposition results.
Submitted by vgarramone on Fri, 05/21/2010 - 10:00
This applet shows a simple database that attempts to prevent users from querying sensitive information, in this case salaries by name. The only queries allowed are a list of names based on selected values for fields, and average salaries for the selected criteria. However, by structuring queries in a certain manner, sensitive information can be inferred from the results.
Exercises are conceptual, and do not require programming/SQL knowledge.
Submitted by vgarramone on Fri, 05/21/2010 - 00:10
This applet provides students with several tools to visually explore the substitution cipher and ways to decipher the code.
Both letter and digram frequency can be used to decode a secret message, and are given as graphs. A suggested experiment and explanatory text are also given.
Submitted by vgarramone on Fri, 05/21/2010 - 00:04
This applet shows how the simple shift cipher works, and provides a visual mechanism to explore breaking the cipher using letter frequency in the ciphertext.
This resource includes a suggested activity and explanatory text.
Submitted by vgarramone on Thu, 05/20/2010 - 23:45
This resource consists of a Java applet that allows students to visually explore how the Affine cipher works, and effective methods of breaking it.
Currently, there are two suggested experiments, a mathematical description of the Affine cipher, and explanatory text for major components of the applet.
Submitted by vgarramone on Thu, 05/20/2010 - 23:34
This applet generates many random key pairs for RC4. The two keys are then each used to generate a stream of 256 bytes, and the two streams are subtracted. The statistics for the resulting list of differences are then stored and averaged over many runs.
Four representations are given, each showing a different aspect of the relationship between the RC4 key and cipher-text.
The purpose of the passwords web lab is to teach you some fundamental concepts about passwords, the most common mechanism used to provide access control to computers, services, and resources. We are all familiar with creating them, using them, and trying to remember them for everything from getting into our email account to purchasing the latest online gizmo. These pages will describe different aspects of password strength, selecting passwords, and cracking passwords and give you an opportunity to experiment with different approaches.
