Math 395 (An Introduction to Cryptography)

Prof. Weibel

Spring 2002

Homework Assignments

All assignments are due on Tuesdays.
Due dateSection/Problems Section/Problems
1/29/02your name in Caesar, k=13 1.1#6,14; 1.2#13,18; 1.3#1; 1.4#1,6,9,12,19
2/5/02Cryptoquote VQVRQ VIWVR QWHHW GTRVG WUNCT FWRRW DHWCV WBKWG TBGFW RRTYF WITBE - YA RKBQQ WFFWGJW 2.3.01, 2.3.02, 2.4.03 (affine),
3.1.03, 3.1.04
2/12/02Jumbles TYMIA ZEROF HYNWIN FLOWEL 3.2.07,3.2.09, 3.3.06,3.3.12,
3.4.01, 3.4.02,3.4.09,3.4.10, 3.5.01,3.5.02
2/19/02If G is good, B bad Riffle on deck of 12, compute the cycle decompositions of GB, BG, GBG-1 4.1.01,4.1.06,4.1.08,4.1.09, 4.3.01,
4.3.04, 4.3.06
2/26/02Decrypt Vigenère handout, compute its indices of coincidence for shifts 4,5,6 4.4.05,4.4.10, 4.5.02,4.5.03,4.5.06
3/4/02Find key for: Hill cipher B=3, e(DAABBACDB)=(DUDDABIFK) and
Affine Hill B=2 e(GAHFBC)=(XIABIA)
8.1.01,8.1.02
decrypt Hill HBBBABSBIIHI probable word 'BEARS', B=2
3/11/02
(DES)
1) Find subkeys if 64-bit key is [100...0];
2) Encrypt [0...0] using one round of DES with subkey [11...11];
3) Which inputs yield F from S-box#1?
4) Find DES' Initial Permutation 6.1.01, 6.2.01, 6.2.02,
7.5.03, 7.5.04
(homework details on handout)
4/2/02 Describe numbers, polynomials and protocol to find secret combination 203   (see handout) Need 2/3 and 4/6 on two committees to consent; one (x,y) is the same for both
4/9/0210.2.1, 10.2.4, 10.2.7, 10.2.8,    10.4.1, 10.4.2, 10.4.3 12.5.1, 12.5.2,   13.7.2, 13.7.9
4/16/02Build a square-root oracle for n=55
and use it to factor 55
12.6#3,4,9,10; 12.7#1,6
15.5#1,3,5,6,7
4/23/0216.1.1, 16.1.2, 16.2.3, 16.6.2, 16.6.4, 22.4.1, 22.5.2 (g=2; 2^27=(2^3)^3=285, 211^27=369)
5/9/02Factor 1,000,001 using our attacks 24.1.1, 24.1.2,   24.2.1, 24.2.2

Return to syllabus or to Weibel's Home Page

Charles Weibel / weibel@math.rutgers.edu /Mar. 28, 2002