LAb1
jimpop1998
Module1-FrequencyAnalysisagainstCaesarCipher.docxPlease complete this lab and answer all the yellow highlighted word.
Lab 1: Frequency Analysis against Caesar Cipher
In this lab, you will explore the concept of letter frequency for the English language. You will learn how Caesar cipher works. You will decrypt a Caesar-ciphered text by first performing frequency analysis and determining the shift value (key). You will complete the first 12 steps on your computer and use the CrypTool installed on the Netlab environment in the rest of the steps.
Lab Instructions
1) Open a web browser on your computer.
2) Search the term "English Letter Frequency" to search the average frequencies of the letters in the English language.
Type the most frequent letter in English:
Type the usage ratio (percentage) of the most frequent letter:
The reference (the URL of the webpage):
3) Search the term "%Your_favorite_city% Wikipedia" by using your favorite search engine. Replace %Your_favorite_city% with your favorite city.
4) Click on the Wikipedia link in the search result to open your favorite city's Wikipedia page.
5) Press CTRL-A to select all the text on the page, and then press CTRL-C to copy the selected text to the clipboard.
6) Click on this link https://wordcounter.net/character-count to open the word counter web application.
7) Paste the text in the clipboard to the text field on the wordcounter.net by pressing CTRL-V or right-clicking on the empty form and clicking paste.
8) Check the most frequent letter on the right in the Letter Density placeholder.
Type the city you searched for:
Type the most frequent letter in the Wikipedia page:
Type the frequency of the most common letter:
9) Repeat steps 3-8 for a couple of other favorite cities to confirm the most frequent letter.
10) Clear the text field's content on wordcounter.net (by pressing CTRL-A within the text field and then pressing the Del key)
11) Copy and paste the following Caesar-ciphered text to the empty text field on wordcounter.net website:
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Lobvsx sc dro mkzsdkv kxn vkbqocd msdi yp Qobwkxi li lydr kbok kxn zyzevkdsyx. Sdc 3,769,495 sxrklsdkxdc kc yp 31 Nomowlob 2019 wkuo sd dro wycd zyzevyec msdi yp dro Oebyzokx Exsyx, kmmybnsxq dy dro zyzevkdsyx gsdrsx msdi vswsdc. Dro msdi sc kvcy yxo yp Qobwkxi'c 16 ponobkv cdkdoc. Sd sc cebbyexnon li dro cdkdo yp Lbkxnoxlebq, kxn myxdsqeyec gsdr Zydcnkw, Lbkxnoxlebq'c mkzsdkv. Dro dgy msdsoc kbo kd dro moxdob yp dro Lobvsx-Lbkxnoxlebq mkzsdkv boqsyx, grsmr sc, gsdr klyed csh wsvvsyx sxrklsdkxdc kxn kx kbok yp wybo drkx 30,000 uw2, Qobwkxi'c drsbn-vkbqocd wodbyzyvsdkx boqsyx kpdob dro Brsxo-Berb kxn Brsxo-Wksx boqsyxc.
Lobvsx cdbknnvoc dro lkxuc yp dro Bsfob Czboo, grsmr pvygc sxdy dro Bsfob Rkfov (k dbsledkbi yp dro Bsfob Ovlo) sx dro gocdobx lybyeqr yp Czkxnke. Kwyxq dro msdi'c wksx dyzyqbkzrsmkv pokdeboc kbo dro wkxi vkuoc sx dro gocdobx kxn cyedrokcdobx lybyeqrc pybwon li dro Czboo, Rkfov, kxn Nkrwo bsfobc (dro vkbqocd yp grsmr sc Vkuo Wüqqovcoo). Neo dy sdc vymkdsyx sx dro Oebyzokx Zvksx, Lobvsx sc sxpveoxmon li k dowzobkdo cokcyxkv mvswkdo. Klyed yxo-drsbn yp dro msdi'c kbok sc mywzycon yp pybocdc, zkbuc, qkbnoxc, bsfobc, mkxkvc, kxn vkuoc. Dro msdi vsoc sx dro Moxdbkv Qobwkx nskvomd kbok, dro Lobvsx nskvomd losxq k fkbskxd yp dro Veckdskx-Xog Wkbmrskx nskvomdc.
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12) Note the most frequent letter in the Caesar-ciphered text and find the shift value based on the information you discovered in steps 2-9.
Type the most frequent letter in the Caesar-ciphered text:
Type the shift value:
Question
In this lab, you performed letter frequency analysis to determine the shift value in a Caesar-ciphered text. Suggest another method other than frequency analysis to help you guess the shift value.
Reflection Question
In two to three paragraphs (i.e., sentences, not bullet lists) using APA style citations if needed, summarize, and interact with the content covered in this lab. Summarize what you did as a crypto analyst, what kind of vulnerabilities did you exploit, what might have prevented these attacks. In particular, highlight what surprised, enlightened, or otherwise engaged you. You should think and write critically, not just about what was presented but also what you have learned through the session. You can ask questions for the things you're confused about. Questions asked here will be summarized and answered anonymously in the next class.
