CSC-233: Assignment #2, Winter Quarter 2026

Introduction

Remember that all you have to show is a good-faith effort in your work to receive nearly full points for the assignment.

Problem #1

Here is a block of ciphertext:

dct hivynd vx xvvg xvf thrc kltratk vx rvyfkt eawtk dct tzdftit paiad dv mcarc thrc rhn anrfthkt byd wtfj xftsytndpj ad ak nvd dct vbdhanane xvvg byd dct ktfwane hk lftj dv vdctf hnaihpk mcarc gtdtfiantk dct hwtfhet nyibtfk vx h kltratk dcyk dctft kttik dv bt paddpt gvybd dchd dct kdvrq vx lhfdfagetk efvykt hng chftk vn hnj phfet tkdhdt gtltngk rcatxpj vn dct gtkdfyrdavn vx wtfian ax nvd vnt cthg vx ehit mtft kcvd gyfane dct ntzd dmtndj jthfk an tnephng hng hd dct khit dait ax nv wtfian mtft gtkdfvjtg dctft mvypg an hpp lfvbhbapadj bt ptkk ehit dchn hd lftktnd hpdcvyec cyngftgk vx dcvykhngk vx ehit hnaihpk hft nvm hnnyhppj qapptg vn dct vdctf chng an kvit rhktk hk madc dct tptlchnd hng fcanvrtfvk nvnt hft gtkdfvjtg bj bthkdk vx lftj twtn dct daetf an angah ivkd fhftpj ghftk dv hddhrq h jvyne tptlchnd lfvdtrdtg bj adk ghi

I would like you to continue exploring using computer resources such as the one found here to assist you as you learn about cryptography. Also look for hints such as repeated letters or bigraphs and trigraphs. For example, once you know a few letters, perhaps use the site's "pattern recognition" tool on one or more longer words in the ciphertext. The above resource can help you with these as well. Explore!

1. Figure out how to generate a letter frequency analysis of the above block of ciphertext. Report the results in your assignment.

2. Report the plaintext.

3. Who wrote this text?

Problem #2

1. Using the Affine Cipher with key: (17, 12) encrypt the phrase: TOP GUN, LEAD PLAYED BY: TOM CRUISE. Remember to report your ciphertext in a non-revealing pattern by grouping in 4s. Be sure to ignore punctuation, fill in extra characters if needed) as has been discussed in lecture.

2. Given the same key (17,12), decrypt the following ciphertext: JEOWD. Be sure to show your work in terms of the formula for decryption including the determination of the multiplicative inverse.

Problem #3

Simply introduce yourself in the class discussion forum. Please state what you prefer to be called (if different from your official "roster" name), your major, and something about yourself. You can keep it as long or short as you like. It's just nice to know a little something about the people in our little community for this course.

Submission Requirements

• Submit your assignment to D2L in either Word (docx) or PDF format.