Cryptography - plaintext to ciphertext to preserve confidentiality.

What is the secret?

  1. Examining the HTTP protocol with ethereal. Downloading a web page without using a web browser client like Konqueror or Netscape or Internet Explorer. Using telnet to connect to port #80 and speak the www or http protocol. How is this like Monday's class and handout where we connected to port #25 and gave commands in the format and language of the SMTP protocol?

  2. Using the ethereal program. Day #3. Seeing the three-way handshake of TCP. Study pages 108-109 of Chapter 6.

  3. The Caeser enciphering of UNI Panthers using every possible key. There are only 25 keys.

  4. Assignment #1 is now posted (Wednesday) and will be due on Monday.

  5. Pretty Good Privacy

  6. IP numbers and class A, class B and class C networks. We did NOT cover anything about subnet masks, but the class A, B and C material will be useful to help you understand today's class and the 0xxxxxxx, 10xxxxxx, and 110xxxxx A, B and C network divisions. UNI is a class B network, and 134 in binary is 10000110. The address of the UNI web server at is and the address of the UNI College of Natural Sciences web server is Please IGNORE the subnet mask material, we will cover that later on.

  7. We used the following commands to find out the IP number of