Homework 1.3

# Homework 1.3 - Instructions All assignments must be typed...

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Instructions: All assignments must be typed; no hand-written assignments will be accepted. You must name your file as: your_last_name_your_first_name_HW# Acceptable file formats: .doc, .docx, .pdf Inside the file, you MUST include your full name, otherwise your HW will not be graded. Do not just give answer. You must show your work. Otherwise you will not get any points CIS 3360 – Security in Computing Spring 2016 Homework 1.3 (50 points) 7) [10] Encrypt the message "COMPUTERSECURITY" using the Vigenere cipher with the keyword "BLUE". C O M P U T E R S E C U R I T Y B L U E B L U E B L U E B L U E (2 + 1) mod 26 = 3=D (14 + 11) mod 26 = 25=Z (12 + 20) mod 26 = 6=G (15 + 4) mod 26 = 19=T (20 + 1) mod 26 = 21=V (19 + 11) mod 26 = 4=E (4 + 20) mod 26 = 24=Y (17 + 4) mod 26 = 21=V (18 + 1) mod 26 = 19=T (4 + 11) mod 26 = 15=P (2 + 20) mod 26 = 22=W (20 + 4) mod 26 = 24=Y (17 + 1) mod 26 = 18=S ( 8+ 11) mod 26 = 19=T (19 + 20) mod 26 = 13=N (24 + 4) mod 26 = 2=C = D Z G T V E Y V T P W Y S T N C 8) [10]Encrypt the message "ITSCOOLGOINGTOSCHOOL" using the Playfair cipher and the keyword "ORLANDO".

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Key: O R L A N D B C E F G H I/J K M P
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Unformatted text preview: Q S T U V W X Y Z IT SC Ox OL GO IN GT OS CH Ox OL KS X(I/J) LV RA PD ML KP LP B(I/J) LV RA =KSX(I/J) LVRAPDMLKPLPB(I/J)LVRA 9) [20] If a cryptosystem has 2 51 possible keys, and you have 800 computers, each which can try 400,000 keys a second, in how many days would you be able to recover the key, assuming that you can immediately recognize when you've attempted decrypting with the correct key? (Assume there are 86,400 seconds in a day.) (800 computers)(400,000 keys/sc/computer) = 320,000,000 (320,000,000 keys/sec)(86,400 sec/day) = 2.7648 x 10 13 keys/day (2 51 keys) / (2.7648 x 10 13 keys/day) = 81 days 10) [10] Given the input 1001011001011100 2 and the permutaTon table below, what would be the output be afer applying our input to the permutaTon table? (Please give your Fnal answer in the ±orm o± a binary number, not a permutaTon table.) PermutaTon table: 1 6 1 1 2 5 1 5 2 1 1 6 1 4 3 1 7 1 3 4 9 8 1 0 0 1 0 1 1 0 0 1 0 1 1 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 16 1 12 5 15 2 11 6 14 3 10 7 13 4 9 8 0 1 1 0 0 0 0 1 1 0 1 1 1 1 0 Output: 0110000110111100 2...
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• Spring '10
• Guha
• Cryptography, 81 days, 86,400 seconds, 86,400 sec, M P U T E R S E C

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