Wed Jan 30 11:00:08 2002 : OK, I think this works. Let me know if you have any trouble.

Wed Jan 30 16:15:19 2002 : hey john, just wanna say thanks for the online notes. im finding them quite useful.

Tue Feb 26 02:29:07 2002 : This last problem set was ridiculous. Why are we wasting our time doing pointless calculations? What do we learn by decrypting SDES by hand? It seems that the problem sets are full of long, boring computation and no interesting math.

Wed Feb 27 21:46:55 2002 : Problem sets are not boring. Those who plan to become cryptographers or cryptanalysts should learn how to be patient. As a cryptanalyst you may need to spend hundreds of hours to decrypt some little message!

Thu Feb 28 22:07:39 2002 : Can some one tell what does RSA stand for?

Thu Feb 28 22:56:00 2002 : R.S.A., named after the guys who proposed the method in the late 70's (1978??), stands for Rivest, Shamir, and Adleman. -x

Tue Mar 5 18:30:18 2002 : For a short bio of R. D. Carmichael (1879-1967) see:

Tue Mar 5 18:37:40 2002 : For more info on R. D. Carmichael (1879-1967) see also:

Fri Mar 8 10:13:12 2002 : There is a photo of Robert Daniel Carmichael at this site:

Mon Mar 18 20:48:23 2002 : I kind of like the "no final" idea and in my experience take-home tests have been very, very difficult. However, if we have to do "projects" at the end instead of a final, then perhaps these will be just as difficult. Perhaps if these "projects" were explain a little more we could decide between a difficult final and difficult projects.

Tue Apr 16 17:01:47 2002 : The cryptographer who proposed El Gamal cryptosystem is: Taher El Gamal Most probably he is from Egypt. This is a typical Egyptian family name.

Thu Apr 25 13:45:31 2002 : what's brown and sticky? give up? a stick.

Sun Apr 28 16:56:58 2002 : No cryptic messages, please.

Tue Apr 30 16:31:04 2002 : 1000111 0011110 11100011 111001

Fri May 3 10:22:19 2002 : I needed more time to complete the course evaluation form. Besides, the form is very lame. So, I continue here. Well, I would like to thank Professor Lenstra for his excellent class and teaching. The class was very absorbing; I did not even blink when he was lecturing. Now looking back at what was taught, I can see a lot was covered. Using some of the tools I learned in this class, I am on my way to become a cryptographer. I would also thank John for providing class notes; really professional. Also, it was very nice when Professor Lenstra told us a little about the Dutch Royal Family. Too bad that his cookie box was empty! I did not know there are still queens. I thought queens were only in books, such as, Alice in Wonderland, where the Queen of Hearts keeps telling "Off With Her Head." Overall, my evalution of the course is: Two Thumbs Up.