Announcements will appear for awhile on the course home page and then be archived here.

• 19 Nov. I should have been more explicit in problem 39 to say that I expect you to write and submit a general program for recovering the secret from four shares of a (2,4) Shamir secret sharing scheme where one of the shares may be bad. You should then use your program to solve problem 12.4.3 as stated in the textbook. As usual, I expect the program to be written in C, C++, or Java. Sorry for not being clear in the problem set.

• 17 Nov. Problem set 8 is ready. It is due in class on Thursday, December 1.

• 17 Nov. Oops! Problem numbering for solutions to problem set 5 was wrong in my original posting. Revision 2 corrects this.

• 17 Nov. I have posted solutions to problem set 5.

• 10 Nov. Problem set 7 is ready (pdf). It is due in class on Thursday, November 17.

• 9 Nov. I have posted solutions to problem set 4.

• 3 Nov. Here are draft notes for the rest of the lectures before Thanksgiving break. I have started the convention of giving them revision number 0. When they get replaced by the "released" versions (without the "Draft" designator), I will change the revision number to 1:

  • lecture 19
  • lecture 20
  • lecture 21
  • lecture 22

• 2 Nov. Notes for yesterday's lecture 17 are available. Notation has been revised from the previously-posted draft to remove the ambiguous use of the letter m in section 1.2.

• 1 Nov. Problem set 6 is ready (pdf). It is due in class on November 8.

• 31 Oct. Here are the notes for last Thursday's lecture 16 and draft notes for this week's lecture 17 and lecture 18.

• 27 Oct. I have posted solutions to the midterm exam.

• 26 Oct. In Problem 22 of problem set 5, Alice tried very hard to choose RSA exponents e and d so that Eve couldn't factor n, even using using the method of lecture notes 12, section 1.3. Alice succeeded wonderfully! Unfortunately, she found that she also couldn't decrypt messages encrypted with her public key. She decided to to change e and d but to leave n the same. Her new RSA exponents are shown in revision 2 of problem set 5 (pdf). All of you who would like to break the code of getting a good grade on this problem should replace the original problem assignment with this revision. Many thanks to Ryan Gephart for pointing out Alice's mistake.

• 25 Oct. Problem set 5 is ready (pdf). It is due in class on November 1.

• 25 Oct. Here are the notes for today's lecture 15.

• 25 Oct. Oops! I posted lecture notes 14 before adding the section on digital signatures, which were discussed at the end of the lecture. Lecture Notes 14, revision 2, now posted, corrects this.

• 25 Oct. I have posted notes for last week's lecture 13 and lecture 14.

• 20 Oct. The TA will go over the mideterm exam solutions on Monday, October 24, at 8 pm in AKW 400. If you don't understand one of the exam questions or don't know why points were taken off of your paper, this is the time to come and ask questions.

• 20 Oct. The solutions to problem set 3 that I posted two days ago contained an error for problem 15. The wrong number had been copied into the Java program used to calculate the answer. Revision 2 corrects this error. Thanks to Ivan Ip for spotting this.

• 19 Oct. Problem set 4 is ready (pdf). It is due in class on October 25.

• 18 Oct. I have posted solutions to problem set 3. A Java program solving problem 15 is in the course directory /c/cs467/course/assignments/ps3 on the Zoo.

• 17 Oct. I have updated the lecture 11 notes to revision 2, adding a new section 2.2 which makes use of the Chinese remainder theorem. I have also posted notes for lecture 12 as well as draft notes for tomorrow's lecture 13.

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• 11 Oct. As was pointed out in class today, the HTML version of the study guide for the midterm examination (handout #8) was bad. I had used the LaTeX comment package to comment out lines from an earlier version, but my LaTeX->HTML converter ignored the begin and end comment commands and included the commented-out regions anyway. Rather than fuss with it, I have deleted the HTML version from the web site. The PDF version and the PostScript version have not changed and should both be correct.

• 11 Oct. Reminder: the midterm exam is Thursday, October 13 at the regular class time and place. It covers the topics of lectures 1--11 (through Thursday, October 6) but not today's lecture. The exam is closed book. Calculators are permitted but no PDA's, laptopts, or other devices with text storage capabilities. Graphing calculators are okay if the memory is cleared before the exam --- check this out with the TA before the start of the exam. Good luck!

• 9 Oct. I have posted solutions to problem set 2. C programs solving problem 9 and problem 10 are in the course directory /c/cs467/course/assignments/ps2 on the Zoo.

• 9 Oct. I have posted solutions to problem set 1.

• 9 Oct. I have posted a study guide for the midterm examination (.pdf).

• 9 Oct. I have revised the lecture 10 notes, adding a new section 6. The current revision is 2. I have also posted notes for lecture 11.

• 7 Oct. I have had some problems with Firefox caching old values of web pages and PDF files and not noticing when the version on the web site changes. If this is a problem for you, click on "refresh" each time you visit the course web site. For the downloaded PDF files, the only way I know to force a refresh is to go Edit->Preferences, click on "Privacy", and then clear the cache. For the revised lecture notes just posted, lecture 9 is revision 2, and lecture 10 no longer says "DRAFT".

• 7 Oct. I have finished some fairly substantial revisions to the lecture 9 and lecture 10 notes. Please replace any old copies you may have printed out with the current ones.

• 7 Oct. The TA will hold a review session on Monday, October 10, at 8 pm in AKW 400. Please come with questions. If you haven't done so already, you will need to get your Yale ID card registered for after-hours access to AKW.

• 4 Oct. Problem set 3 is ready (pdf). It is due in class on October 11. Note that this assignment also involves writing one program. As before, programs should be submitted online.

• 3 Oct. I've just posted the notes for lecture 8 and lecture 9. together with draft notes for tomorrow's lecture 10. They will be revised after the lecture to reflect what I actually covered in the lecture.

• 29 Sep. The midterm exam will be held on Thursday, October 13.

• 29 Sep. I just posted the three supplementary handouts on number theory that I promised: Number Theory Summary, Linear Congruence Equations, and The Legendre and Jacobi Symbols. Please skim through them now and then refer to them later as needed. Because of the extensive amount of mathematical notation used, they are available only in PDF and Postscript form, not in HTML. (Please see the handouts page for links to the Postscript files.)

• 29 Sep. I have installed online submission scripts into the Zoo directory /c/cs467/bin/. These scripts were produced by Professor Eisenstat and are the same as he uses in CPSC 223/323. You should use them for submitting source code, test data, and output from your programs in the programming problems. Please let me know if you run into any difficulties using them.

• 27 Sep. Problem set 2 is ready (pdf). It is due in class on October 4. Note that this assignment involves some programming, so sign up for your Zoo account and start early. Programs should be submitted online.

• 26 Sep. I've just posted the notes for last Thursday's lecture 7 (pdf).

• 22 Sep. I've just posted the notes for last Tuesday's lecture (pdf).

• 20 Sep. The first homework assignment is ready (pdf). It is due in class on September 27.

• 18 Sep. I've posted lecture notes for the first five lectures of the term. These replace the preliminary lecture notes posted previously. Each lecture will be in its own file rather than combining lectures into weekly units. Please report any errors you find in these notes so that I may correct them.

• 1 Sep. Final examination will be given at the officially scheduled time, Saturday, December 17, 9:00 am. Please take this into account when making your end-of-term travel plans. I do not plan to give an early exam for the convenience of those who want to leave campus early.

• 31 Aug. Welcome to the CPSC 467a web site. Look here for announcements and course materials.