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Take Home Exam I – MATH 125 -01

Directions: This exam must be handed in at the beginning of the in-class exam on Friday. You may not use anything but your class notes, class book, and the maplets. You may not discuss the problems with anyone (other than me).

Make sure to break the plaintext into individual words. Show work on the cryptanalysis problems. All work from Maplets should be typed. Each problem should be clearly labeled.

Please attach this signed cover sheet to your work with a staple. Make sure that you include your name on every page of your exam.

Good luck!

I know you are all working hard and I believe in you all.

-Dr. M

Please sign:

I affirm that I have not discussed this exam, its questions, or its content, with anyone. I understand that discussing this exam with anyone, copying answers from anyone (either partial answers or in their entirety), or any other discussion of this exam either in person or on the internet constitutes cheating. I understand the penalties for cheating in this class include a letter being sent to my Dean detailing the cheating offense and a grade of F for this course, from which I will not be able to withdraw.

Signed Part I: Encryption and Decryption.

1. Decrypt the following simple substitution cipher, using keyword martin luther king jr: GCVIHPQUICBGYNCORIRMDMAGICNQOMBPNCOJHBLMBIBIJYHBQCNOHIBT No work is needed. Just type out the plaintext from the Maplet. And then split it into English.

2. Decrypt the following keyword columnar substitution cipher, using keyword seneca: QKUQZRDUFQLRBUSXRJZXNCXSNJRJULQZRGXUZGJUKOLDJWJLRQXKOUGL RSKOSKORQBUXKOUGLRQQO No work is needed. Just type out the plaintext from the Maplet. And then split it into English.

3. Encrypt the plaintext “There is nothing on this earth more to be prized than true friendship.” using a Playfair cipher with keyword thomas aquinas. No work is needed. Just type out the ciphertext from the Maplet.

4. Decipher the simple columnar transposition cipher IPKHL TNOGS USAOT GOLLE IYSGS HADIB SAINO EMHTT ITIME TLTNN VWEOH HLTTU OSYIT AEHLN IEIOC LFPTM TPPOA ENTKL UTIRH PHEEM USKHE ARILO EOIRO AGTII MUETL BMRNS, which was encrypted using 8 columns. No work is needed. Just type out the plaintext from the Maplet. And then split it into English.

5. Decipher the keyword columnar transposition cipher YDOSY OOCNU ATOOP NMPIE RSFAR TRROW BABRT UATTP IEYLL LRAIA ENHTB GOBGT AOODY PYCLA GTHYH UEHTI RCONO GRLBD ITRID RLOEX TONLT DRYRM LICOI NNUIO HUSOU YESYE OCLRC SUTKA ORTUR PLLIG OENYE IALCT WAYEU IEDRS UDNUO UBNRC CIATW KSCEI URGT, which was encrypted using keyword allen klein. No work is needed. Just type out the plaintext from the Maplet. And then split it into English. Part II: Breaking Ciphers. All of the following are to be done using Maplets, but with all work shown (as needed).

6. Break the following random substitution cipher. Make sure you show all work (including digraphs and trigraphs) and give your complete reasoning as to how you solved the cipher. S IMBZ ETZ VWQN. VWQN SB ZXW ISEF-RSUUWN. VWQN SB ZXW USZZUW- FWQZX ZXQZ ANSEGB ZTZQU TAUSZWNQZSTE. S HSUU VQDW IK VWQN. S HSUU PWNISZ SZ ZT PQBB TCWN IW QEF ZXNTMGX IW. QEF HXWE SZ XQB GTEW PQBZ S HSUU ZMNE ZXW SEEWN WKW ZT BWW SZB PQZX. HXWNW ZXW VWQN XQB GTEW ZXWNW HSUU AW ETZXSEG. TEUK S HSUU NWIQSE. - VNQER XWNAWNZ, FMEW Make sure that you split the plaintext up into English.

7. Break the simple columnar transposition cipher WNIHO RRRHS SOLRE FDISE TRIEM MSNFH HDGSI ECGRA ESHIN NATOR ACTND WNEMD RAFTS OWATE T Give a brief explanation for your work, explaining what did and what did not work to break this. Make sure that you split the plaintext up into English.

8. Break the keyword columnar transposition cipher ENAAS THTOA EAITH TEOAX TINTH SATFA SEAAV EDKWS TSCEA MTOKV ALIEG QAOSE HOTHU TCOYM WGLCE SHFNX QSNTT HUHUN RITBI ILRNX STARC OEWIE NHSFI UNOOR UWSTH ESIGA ANTUM OLHSX IEEWE EYHNI NLSLT ANLIW, where you have the crib “him a question”. Make sure you show all work (how you decided on the number of columns, including what did NOT work and why) and give your complete reasoning as to how you solved the cipher. Make sure that you split the plaintext up into English.

Part III: Superencryption. 9. We will again explore the concept of superencryption. This problem is to be done by hand. For this problem,  CIPHER A will refer to a keyword columnar transposition cipher with keyword paul simon  CIPHER B will refer to a keyword columnar substitution cipher with keyword musics

a. First, give the cipher alphabet for cipher B, showing all work. You need to do this by hand, not on the maplet. b. Our plaintext is hello darkness my old friend. We want to superencrypt this. First use CIPHER A to encrypt this and then CIPHER B. Tell me what happens after the first encryption and then what the result is after superencryption. Make sure to give n, c, q, r. c. The ciphertext that you are now given is JSNQN LTFRT RLQAE TBLWT TPDLP MQUNL TNNJM LMWJP PTBPM JTLNT WBQL You have been told that this was superencrypted using CIPHER A first and then CIPHER B. Decrypt, giving a full explanation and showing all work at each stage of the decryption. Make sure to give n, c, q, r.