FTS-100: Secrets, Secret Codes, and Privacy
Fall 2006

Reading and class schedule  Project  FTS-100  homepage
Homework
Short writing assignments  Course description
Homework guidelines
Criteria for grading writing
kaiser@gustavus.edu

Homework  assignments


Due:
Assignment:
Nov. 20
Section 4.4, #1ab, 2ab, 5,6,8
Show your work. 
Note:  Here is a modular arithmetic calculator.  Feel free to use it to calculate powers and inverses, but do indicate what calculations you did.

Nov. 10
Section 4.2, #1bd,2b,3bd,4,6,8,10
Note - #8 as written can't be decoded, you should show me why. 
Also, do #8 but use the number 420.

Section 4.3, #1be,2e, 8 (Note: for 8, I found 11 pairs with e<=d)
Show 2^98 +6^98 is divisible by 29 (see #3)
Do #7, except use the pair e=5 and d=13 instead of the ones Barr gives.

As always, be sure to show your work.
Nov. 3
Section 4.1, #6b,c, 11b,12de, 13b, 14b
Use Fermat factorization to factor 3200399.  As always, be sure to show your work.
Oct. 13
Section 2.5, #1b, 2b, 3bd, 4
Use a spreadsheet to help you do these problems; hand in copies of those parts of  your spreadsheet that you used to encipher or decipher a message.  Be sure that what you hand in is easily read and that you tell me what formulas you used.
I will email a problem like #5 (already in a spreadsheet) to decipher.

Section 2.6, # 4,5b, 6b, 7b,8bd, 11bdf
Be sure to write full sentences that tell me what your answer is and explain how you got it.

Oct. 5
Section 2.3  homework
Section 2.4, #2,4,6
The message below was encoded using a simple columnar transposition.  Decode it.
HCEEW IHLIO MVTEO SMONE LDFAE CMSOR TSEEA NRAPI SDOMS ANIMN RHTST ATSYE E
Sept. 25
Do problems 2, 10, and 14 in section 2.1 of Barr
Do the supplementary problems for section 2.1  (pdf)
Do problems 2bd, 3bf,5bd, 8, 10 in section 2.2 of Barr
Do problem 7 (section 2.2), but use the message (due to Stanley Kubrick):
GENTLEMEN! YOU CAN'T FIGHT IN HERE! THIS IS THE WAR ROOM!

Last modified:  11/15/6