Assignment Cryptography Lab

Here are all the steps that were provided in the assignment. I never reference the first person, that’s it. I just need it by tonight please!

Please answer the following questions. Let me know if you are having any difficulties and I can provide hints. Many times, you need to read the entire question, and youll be able to figure out how to solve it.

Answer these questions in lab format. Use the resources in the Engage shell to help you. Remember, it is perfectly acceptable to collaborate with your classmates on how you arrived at your answers.

1) Caesar Cipher: What does the cipher text below say? Please work this by hand then use the tool at the following link to check your answer. How long did it take you to decipher this message?

https://www.xarg.org/tools/caesar-cipher/

FI JEMXLJYP MR XLI WQEPP XLMRKW FIGEYWI MX MW MR XLIQ XLEX CSYV WXVIRKXL PMIW

2) Vigenere Square Tool Cipher: This exercise is practically the same exercise as above; however, this time encipher the message. You will need to use the Vigenere grid to do this. Use the one at the link below.

The message to encipher is: MEETEIGHTWEDNESDAYBRINGPROPERMATERIALS

The keyword is: UTICACOLLEGEPIONEERS

Cryptography The Vigenere Cipher

3) Vigenere Square: For this exercise, create a message (it can be short; 5 10 words or so). Create a key. Encipher the message; record the result. Use the grid you used to solve question #2, or use another Vigenere cipher tool to help you (you can find a Vigenere grid online, or use the link below to help you. In a few sentences, explain how you worked through this problem. Dont forget to provide screenshots of how you created the message and key, along with the enciphered text.

https://planetcalc.com/2468/

4) XOR Encryption: This exercise uses XOR encryption to encrypt a word made up of four characters. The characters of this word have each been encrypted using XOR encryption. The cipher text of the word is as follows:

00010111

00001100

00000001

00010000

The key is: 01010101

Remember from the computer number systems lab that we examined how XOR works. Look up how XOR works as a review. Take each binary digit and XOR it with each binary digit of the key. This will result in a new 8-bit code. Each 8-bit code is equal to one ASCII character. This new code corresponds to the plaintext.

Use http://www.tech-faq.com/xor-encryption.shtml to guide you through the decryption phase. After you have applied the key to the binary strings above, use the ASCII to binary conversion chart at http://www.pcguide.com/res/tablesASCII-c.html to determine what letter each eight bit string stands for, solving the exercise.

5) Homphonic Cipher: The homophonic substitution cipher is a substitution cipher in which single plaintext letters can be replaced by any of several different ciphertext letters. They are generally much more difficult to break than standard substitution ciphers.

The number of characters each letter is replaced by is part of the key, e.g. the letter ‘E’ might be replaced by any of 5 different symbols, while the letter ‘Q’ may only be substituted by 1 symbol.

The easiest way to break standard substitution ciphers is to look at the letter frequencies, the letter ‘E’ is usually the most common letter in English, so the most common ciphertext letter will probably be ‘E’ (or perhaps ‘T’). If we allow the letter ‘E’ to be replaced by any of 3 different characters, then we can no longer just take the most common letter, since the letter count of ‘E’ is spread over several characters. As we allow more and more possible alternatives for each letter, the resulting cipher can become very secure.

http://practicalcryptography.com/ciphers/homophonic-substitution-cipher/

Using the example and the substitution alphabet from the link above what does the following encoded message say? Its a short quote from William Shakespeare.

AQ PZHDSB VR 40 J3SC 94 CQ51RUB

6) Decryption (Substitution Cipher): The following is a substitution cipher. The letters are substituted randomly. Remember that this is a not shift cipher like the Caesar cipher. What does the following quote say? Who said it? Do this by hand. How long did it take you to decipher this message?

DY JR EAWP D GTCTZ OTTA DYIRZBWGB, DB PRTJ KRYIADKWBT ADOT!

TATWGRZ ZRRJTCTAB

7) File Hashing: Please check out the following link for a fun fact related to the United States Cyber Command, then check it out:

http://www.wired.com/dangerroom/2010/07/code-cracked-cyber-command-logos-mystery-solved/?npu=1&mbid=yhp

http://www.computerworld.com/s/article/9179004/Researcher_cracks_secret_code_in_U.S._Cyber_Command_logo

USCYBERCOM plans, coordinates, integrates, synchronizes and conducts activities to: direct the operations and defense of specified Department of Defense information networks and; prepare to, and when directed, conduct full spectrum military cyberspace operations in order to enable actions in all domains, ensure US/Allied freedom of action in cyberspace and deny the same to our adversaries.

Go to http://www.fileformat.info/tool/hash.htm and copy the mission statement above into the string hash text box. Calculate the MD-5 hash. Do things check out?

8) File Hashing: YOU WILL NEED TO READ THESE INSTRUCTIONS CAREFULLY!

A cryptographic hash function takes an arbitrary block of data and returns a fixed-size bit string. The data to be encoded is often called the “message”, and the hash value is sometimes called the message digest. Hash functions are used for a variety of things, including verifying the integrity of data or messages.

Create a file in Word. Find a paper that you have written as a starting point. Use the hashing tool from question 7, or download HashMyFiles from the following link:

http://www.nirsoft.net/utils/hash_my_files.html

Hash the original file; record your results. Take the original file and create a copy; right click, copy and paste (suggestion save everything on the desktop or in a folder so that everything is organized). Hash the copy and record your results. Next, take the original file and save it as a PDF. Hash the PDF and record your results. Next, take the original and save it in a different version of Word. Hash that file and record your result. The next task is to take the original file and delete a single period or add a single space somewhere in the document and then save it; save is as FILE_MODIFIED. Finally, HashMyFiles will enable you to drag and drop all files at the same time. Hash all the files and record the results. What do you observe?

At the end of this exercise, you should have the following files:
FILE (Original Word document)
FILE (Word document copy)
FILE (PDF document)
FILE (Word document different version of Word)
FILE (Word document from original Word document with a period added or deleted)

NOTE: You can use either the MD5 or SHA1 hash.

9) Transposition Cipher: A user received the scrambled message below. The message was scrambled with a transposition cipher. The receiver knows that the key is 7 columns with 5 letters in each column. What does the message say?

TSTESTIHAOTPIPITFROOHSETASNEISHNICR