Explain Your Approach to Each Problem That You Do

CSC/MAT 483 – 001

Cryptology

Comprehensive Exam

This is a test. You may not collaborate.

It is due no later than noon on Friday, 13 December. It may be submitted electronically or as a hard copy.

Each problem is worth 16points. There is a maximum of 200 points.

Explain your approach to each problem that you do.

You may use software that is posted on the class website, use Mathematica, use a calculator, work by hand, or use software that you wrote.

1. Cryptanalyze

RENYJ RMVHM DNBCR VNJOC NACRV NRENM XWNVH BNWCN WLNKD CLXVV RCCNM WXLAR VNJWM KJMVR BCJTN BRENV JMNJO NFREN QJMVH BQJAN XOBJW MTRLT NMRWV HOJLN KDCRE NLXVN CQAXD PQJWM RWNNM SDBCP XXWJW MXWJW MXWJW MXWFN JANCQ NLQJV YRXWB VHOAR NWMBJ WMFNU UTNNY XWORP QCRWP CRUCQ NNWMF NJANC QNLQJ VYRXW BFNJA NCQNL QJVYR XWBWX CRVNO XAUXB NABLJ DBNFN JANCQ NLQJV YRXWB XOCQN FXAUM

2. Cryptanalyze

QSZLZ NOTMQ SZLZN JTMKV HISZM TEQSH BZYRP HBQSZ JTMKG AZQVS AZN

3. Cryptanalyze

xcqradqdqracgcxvmptednacpnpmlicjracgcxvmptdqlicreaicxbktragcxicrrcpdqb

4. A scrap of paper containing the following is found. Determinethe type of cipher and the key.

difx fi eh el lm an ke ye xc ha ng ex

AM EY CM BK GN DO ND RK XF WE IV LE KN

5. Cryptanalyze

IBFNM PIYSQ WTPJQ WQGSC OQWTB UUTKU RUJHQ VWCOY SWHWP WTGVY PQQPU ISXIV XWTAZ QKCEP AUIOE PVVHY YEMPH CWPIE RYTDB QXHUP ZPHBJ AAEDI QPZCI CWPAC CXFIX GGCFY BKPFM PITCC ORQPP LFLTY DLMOM PKCSZ VOTHU GQCRU JEPGJ HJGMT HCUJL KGYDE TARIO EZKQO UPAVD NIPLG KYMZX OTHUZ NVWYD ZUODH XPINI BBYLV GCTEI VTUSP IDNWP YVGRN JYOVW YCPAV XHGZZ OPNJN AUIOE PVVHJ SZNGH MJZVC AMULN HPHEL ECGXX TVPXH HQIEJ FUJDG GMFOQ PIBFW IVTMU CMUTU SNPCC XJYLW HNSJJ GHNQC IEICD PAYXN IMCUX HFDAG HUOOW TVUOT HCICP YAUTY LTVIT RQPZV XMFEP KHWPW TCQIS LBKDH GZZOH NIPJW XFETV IQFPN SUDZT ECFTH ULKCS YNTKU JWDPA UPHEM CUXHF DAKCH PGIVX IOMWV WFPNI NASBY LYDLM OEKSY BEIPN AJGMP ICNPW WGMUF LGCNT QIEJF UJIPS MULNH PLFPV IPAJY OCKUS TMVNI GLXRA CFOZG HYBCK JELPU MEIMD ZURGC TPLQU NIPKQ BGVYQ EPNJG MVTWI YQEPF BYLEG YBEQX TYMPU GCNTE PCIUS PQPUI SXIVX WT

6. Cryptanalyze

We find another scrap of paper containing

a = 0, b = 1, c = 2, …, z = 25

id on tk no whow to do th is se nd he lp

FV PB KF SJ BH IE EP YZ VE CO EC PO IR TQ

Determine the cipher and the key.

7. Cryptanalyze

tttrhietyeyespilwtcmahcqiaorkbweoioqhshmrhikukpqhripesyhwdwriscbyeiadtdqtopeocheseiqsnnoelhsrnrqeietdlsesehq

8. Complete the following key

abcdefghijklmnopqrstuvwxy z

V EC T I YA DF LMN Q U

9. The following ciphertext was discovered on a scrap of paper:

HBVKEHOYLBFMVNEFESTILQBFRAZM

On another scrap of paper is:

Our great suburban location just minutes from the vibrant Cincinnati metropolitan area offers you the quality and security of an engaged community and the recreational and employment benefits of a big city.

Cryptanalyze the ciphertext.

10. On yet another scrap of paper:

nku

GRCYZUYMUSFICJGERVLVM

Cryptanalyze the ciphertext.

11. Generate an RSA key. Use primes in the range between 20 000 000 and 30 000 000.

12. Use the RSA key that you generated in problem 11 to encipher at least 5 characters of your first name. (Pad with X’s if necessary.)

Use

a = 0, b = 1, c = 2, …, z = 25

to substitute for the letters.

13. More scraps of paper … . We see the Baudot code, the following string of digits

1415926535897932384626433832795028841971693993751058209749445923

and

00011 10111 01001 11010 00110 11011 11001 00010

Cryptanalyze the message.

14. Do the following calculation in where the modulus is . Numbers are given in hexadecimal.

15. Use simplified AES to encrypt the plaintext 1010 0111 0001 1101.

The user supplied key is

1010 0111 0011 1011

The following keys were constructed using the key schedule.