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:

2 Nov. Notes for yesterday's lecture 17 are
available. Notation has been revised from the
previouslyposted 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.


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 commentedout
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 111 (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 afterhours 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 endofterm 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.