CS 200 - Fall 2024. 11/20/2024

I hereby solicit suggestions for the video of the day. Please email me your ideas with explanations. Selected entries will win 5 homework points. If your video is played at the beginning of class, you must also briefly explain something about the video and something about yourself — in person.

Logical problem of the day

1994, 1998, 2000, 2006, 2016, 2022, ...

https://pollev.com/slade You may also download the app to your phone. Use the "slade" poll ID.

Image of the Day

Answers to hw7

Canvas Quiz of the Day (need daily password)

Click for today's quiz.

Lecture 23: Cryptography.

Announcements

We are working with The Percentage Project, which is an upcoming nonprofit organization and leader in data-driven advocacy with the goal of helping inform departments and students in the country about the status of diversity and inclusion in their CS and Engineering departments. It is similar to CRA's Data Buddies program but we focus more on student involvement, social advocacy, and collaboration across schools.

This semester, the Percentage Project will be conducting a brief anonymous survey for students at Yale who are studying computer science and related fields, and we would love to have CPSC 200 and 201 students in the survey.

The survey is completed with the following general survey link: https://bit.ly/ppyale24 . Additionally, any student who completes the survey has the opportunity to win free coffee/tea/boba of their choice.

The annual nationwide survey of CS departments (a.k.a. “Data Buddies”) is now live: https://cerp.co1.qualtrics.com/jfe/form/SV_e42au8zqmjbYvVI/?id=yale_cs

This survey measures retention and persistence among CS students, including undergraduate majors, non-majors, and graduate students. It is the main tool that the department will be using to both gauge our educational efforts, and compare against peer CS departments.

It is run externally by the Computing Research Association, which only provides aggregate data. At no point will we have access to individual answers or identities.

We will be using the survey results to set and prioritize future department initiatives, so this is a great chance to have your voice heard. Please fill it out!

Note: in other classes, students are given late day extensions as incentive to complete the survey. Here, that is like bringing coals to Newcastle. Just do the right thing. Your voice matters.

If you fill out this survey, then you will also be given the opportunity to enter a raffle to win one of five hundred $25.00 Amazon gift cards!

Administrivia

Note that hw7 has two autograders: hw7a for questions 1-3 and hw7b for questions 4-6.

Final Exam

Here is a practice final exam and practice final solutions.

Here are the important concepts from Stamp:

• CIA
• Caesar cipher
• Substitution cipher
• Transposition cipher
• Kerckoff's Principle
• Complexity of brute force attacks (exhaustive key search)
• Secure vs insecure ciphers
• One-time pad

Shell scripts: I might ask you to write a shell script. You should know the for loop.

The following topics were part of this course and are in scope for the final:

• Python
• recursion
• list comprehensions
• memoization
• decorators
• exceptions
• UNIX including bash shell scripts
• regular expressions
• object oriented programming
• data structures: stacks, queues, hash tables, heaps
• SQL
• Machine architecture
• Python byte code
• cryptography

If your grade on the final exam is higher than your lower midterm grade, it will replace that grade. The quality of mercy is not strained.

Alas, we did not get to machine learning. See scikit learn aka, sklearn. Python module for machine learning. Machine learning jupyter notebook

Cryptography

2024 CrowdStrike-related IT outages

Cryptography notebook Chapter 2.

See hw7hints.py You may need to install the module: wordsegment.

pip install wordsegment
  

Getting to know UNIX