Assignments for Crypto

Homework assignments after first exam.

Feb 7 2.7 Friedman test and 2.7(1-4,7) and handout (see blackboard)  
Feb 12 3.1/3.2 binary, base 26, boolean function 3.1(1-6,8,10,12-14) 3.2(1-4)  
Feb 14 3.3/3.4 computational complexity/stream ciphers 3.4(1-9) and write a program (in maple, or excel, or ...) to generate keystreams for 5 and 6 bit registers. Find a register and an initial fill that generates the maximal period of 2^n-1. Does it matter what your initial fill is for the period?  
Feb 19 Finding LFSR's of maximal length (not in text -- there are some references on blackboard) handout (see blackboard) and study for quiz  
Feb 21 2.9 and 1.1 Block ciphers: Playfair and Hill handout (see blackboard) QUIZ 2: 2.6,2.7, 3.1,3.2
spring break      
mar 4 3.5 DES handout (see blackboard)  
Mar 6 3.6 Hash functions handout (see blackboard)  
Mar 11 Diffie Hellman Key Exchange and modular exponentiation study for test  
Mar 13 EXAM 2 sect 4.5(1-5) and find a 4 digit prime and a good base for DH key exchange  
Date Material Discussed HW Assigned due next class period Quiz?
Mar 13 EXAM 2 Sect 4.5(1-5) and find a 4 digit prime and a good base for DH key exchange  
Mar 18 El Gamal Cryptosystem Sect 4.5(6-10) and read hash article in blackboard  
Mar 20 RSA, part 1 handout on Euler phi phun  
Mar 25 RSA, part 2 -- fermat's thm handout on FLT QUIZ on DH and El GAmal
Mar 27 RSA part 3 4.4(2-9) -and-
set up your own RSA system. Tell me your public exponent,e, and modulus,n. Encrypt a message to me using base 26 on blocks of 3 letters and using your SECRET exponent,d. That is, for a message,M, tell me CT=M^d mod n (in blocks corresponding to 3 letters each).
So tell me e,n, and CT and keep secret d,p,q,phi(n).
Bonus problems:
4.5(10) and/or write a maple program to do base 26 conversion back and forth for 3 letter blocks.
Apr 1 RSA, digital signatures, factoring take-home quiz see blackboard  
Apr 3 no class, take home quiz take-home quiz see blackboard TAKE-HOME Quiz
Apr 8 more factoring handout see blackboard  
Apr 10 summary and review study for final!  
Apr 16 Final Exam at 3pm    

 

homework from before first exam.

HW Due Thursday Jan 31
2.5(5,6), 2.7(6,8) {use maple program in blackboard}
Read 2.6 and do 2.6(1,2,5-10)


HW Due Tuesday Feb 5
Study for first exam


HW Due Thursday Feb 7
2.6(11-13,15)


HW Due Tuesday Feb 12
2.7(1-4,7) and decrypt messages in blackboard file
AND 3.1(tba)?

OLD HOMEWORK
HW Due Tuesday Jan 29
2.4(1,2,5,6,7)
And Decrypt the following ciphertext encrypted with a column transposition (no keyword)
DGIMT GSTRO NAHUA HANEN EAIIW MCDLG DNIYO OAENG NFMFN IO
-AND-
2.5(1-4)
-AND-
study for short quiz on 2.1-2.3 on Tuesday


HW Due Thursday Jan 24
Read 2.3 and do 2.3(1-7,9,10)
Bonus 2.3(8)


HW Due Tuesday Jan 22
Read 2.2 and do 2.2(4,5,9,10,12,13,15) AND finish the handout from classBonus: 2.2(14) and write a maple program to solve modular equations of the CT=aPT+b mod 26 with 2 equations, where CT and PT are known and you are solving for a and b.


HW Due Thursday Jan 17
part 1: do 2.2(1,2,3,6)
AND
part 2:
A) Analyze the maple code that I gave out in class today. Figure out as much as possible what each line does.
B) Then adjust the code to encrypt messages with the affine cipher where CT=aPT+b. Hint: there's only one line you need to change.
AND
part 3: Use your above adjustment to the maple code for 2.2(7,8).Assignment for Tuesday Jan 15
Complete all of the assignments from previous set. In particular, we will discuss all the problems from 2.1 AND
Read the Sherlock Holmes story at the link below and be prepared to describe what you learned about monoalphabetic ciphers from it.
http://www.trincoll.edu/depts/cpsc/cryptography/holmes/dancingmen.html
You can also check out Edgar Allen Poe's The Gold Bug at http://www.easylit.com/poe/comtext/prose/goldbug.shtml


1) Email me your answers to the following questions:
- What are you majoring in and why?
- What math courses have you taken so far at Redlands?
- Why are you taking this course? What do you hope to learn in it?
- Construct a metaphor for mathematics (as you see it). For example, if math were an animal what would it be? Explain why you chose your metaphor.
- Please tell me anything you think I should know about you, and/or anything you?d like to tell me about yourself.
- Is there anything you?d like to know about me?
2) Read Section 2.1 of Barr and do 2.1(1-6, 11-15).
3) BONUS Problem: Solve an online cryptogram at http://teppo.tv/cryptogram/ or
http://www.cryptograms.org/