CS513: Announcements Archive

• Comments on Phase III grading.

• Phase III now available for download here. [posted April 3, 2004].

• No lecture on Tuesday April 6. [posted April 3, 2004].

• Grades for Phase 1 are now available through CMS under assignment "Phase I Grade". Clicking on "Solutions" gets access to notes on the grading criteria. [posted March 12, 2004].

• Detail notes on Lamport's one-time password scheme are now on-line for those who seek clarification. [posted March 10, 2004].

• No lecture on Thursday March 4. [posted March 2, 2004].

• More Project 1 Hints. A bug has been discovered in the .NET library. It is not possible to serialize to a CryptoStream that is attached to a NetworkStream because the Deserialize call on the receiving end of the stream will block until the stream is closed by the sending end. You might note that all the MSDN examples use a backing MemoryStream, so perhaps this behavior is expected, but not documented.

  A simple rule to avoid this problem is: never attach a CryptoStream to a NetworkStream. We sketch a possible implementation strategy:

  • Use a CryptoStream attached to a MemoryStream. You can serialize objects to this structure, then safely close the stream. Then, get the byte array from the MemoryStream and write (or serialize, if part of a larger object) it to the NetworkStream. On the receiving side, reverse this process: recover the byte array, decrypt the bytes, then deserialize the result.

  Please take advantage of the additional TA office hours if you are having difficulties with this (or any other) part of the project.

• Project 1 Hints. Based on questions the TA's are getting, the following information should prove useful:
  • The CryptoStream.FlushFinalBlock method already implements padding for you. So, if you think that you need to write any additional code for sending or receiving messages that are shorter than the block length, you probably are not using the CryptoStream class correctly.
  • C# streams, in conjunction with BinaryFormatter, can be used to send entire object graphs across the wire. So if your code only sends and parses strings, you're missing out on an elegant mechanism. And, you're likely making your life much more difficult --- if not now, then in later phases of the project.

• Additional TA office hours for the week of Feb 23. To help you complete Phase 1, we have scheduled additional office hours for evenings and next weekend. A TA will be available in room 309 Upson, as follows:
  • Tue. 2/24: 7:30 pm - 9:00 pm (Benyah); 9:00 pm - 10:30 pm (Andrew)
  • Wed. 2/25: 7:30 pm - 10:30 pm (Benyah)
  • Thurs. 2/26: 7:30 pm - 10:30 pm (Andrew)
  • Fri. 2/27: No additional evening office hours.
  • Saturday 2/28: 12:00 pm - 3:00 pm (Andrew); 3:00 pm - 5:00 pm (Kevin)
  • Sunday 2/29: 2:00 pm - 3:00 pm (Andrew); 3:00 pm - 5:00 pm (Michael)
  • Monday 3/1: 7:30 pm - 10:30 pm (Michael)
  [posted Feb 23, 2004]

• Revised TA office hours for the week of Feb 23. Due to the Wed Bill Gates lecture and various TA travel, TA office hours for the week of Feb 23 are changed:
  • Monday 3:00-3:30. No office hours.
  • Wednesday: 3:00-3:30. No office hours.
  • Thursday 11:30-1:30. No office hours.
  [posted Feb 22, 2004]

• TA office hours for this course commence Monday, Feb 16. A schedule is now posted.
• Revised TA office hours for the week of Feb 23. Due to the Wed Bill Gates lecture and various TA travel, TA office hours for the week of Feb 23 are changed:
  • Monday 3:00-3:30. No office hours.
  • Wednesday: 3:00-330. No office hours.
  • Thursday 11:30-130. No office hours.
  [posted Feb 22, 2004]

• TA office hours for this course commence Monday, Feb 16. A schedule is now posted.

• Special lecture: John Manfredelli, the head of Windows Security for Microsoft and one of the chief architects of NGSCP (formerly known as Paladium) will be lecturing in the CS Dept Colloquium on Thurs. Feb 12, 4:15pm Upson B17. [Posted Feb 9, 2004]
• Notes for Kevin Hamlen's lecture on Monday night, Feb 9 can be downloaded from here. [Posted Feb 9, 2004]
• CS513 student accounts for CSUGLAB are now enabled. Click here to access your account and reset/change your Windows and UNIX/Linux password. User authentication (Cornell NetID and password) is required to access the above information.
  If you need a refresher, you can find a discussion of CSUGLab policies and resources here. [Posted Feb 2, 2004]
• Monday night session:
  Feb 9, 730pm - 930pm, Upson B17: Introduction to C# for Java Programmers [Posted Jan 27, 2004].