Math 187A (Winter 2026) [To be updated]

January 16: Quiz 1

January 14: [Planned: 2.6, 2.7]

Jnauary 12: [Planned: 2.5, 2.13, 2.6]

January 09: Discussed Rectangular transposition and defined what it means for two integers to be equivalent mod n: a ≡ b (mod n) if and only if n divides (b-a), or equivalently, a and b leave the same remainder when divided by n. [2.2, 2.5]

January 07: Introduced Simple Substitution cipher, Polybius square (ADFGVX cipher), and Playfair cipher with many examples. [2.8, 2.9, 2.12]

January 05: Went through the Syllabus. Gave a quick history of cryptography. Saw how to execute Caesar cipher with an example.

Lecture Time: MWF 11:00am to 11:50am
Lecture Location: Pepper Canyon Hall Room 106
Textbook: An Introduction to Cryptography, by Shishir Agrawal. Available online via this link.

Discussion Section:
Section A01: M 5:00pm-5:50pm at HSS 2321
Section A02: M 6:00pm-6:50pm at HSS 2321
Section A03: M 5:00pm-5:50pm at CENTR 203
Section A04: M 6:00pm-6:50pm at CENTR 203
Section A05: M 7:00pm-7:50pm at CENTR 203
Section A06: M 8:00pm-8:50pm at CENTR 203

Course Personnel:
Instructor: Karthik Ganapathy Venkitachalam
Teaching Assistant for Sections A01 and A02: Nathan Wenger
Teaching Assistant for Sections A03 and A04: XXX
Teaching Assistant for Sections A05 and A06: Jianxiang Tan
Note: To contact us, please use Piazza. The system is highly catered to getting you help fast and efficiently from classmates, the TA, and myself. Rather than emailing questions to the teaching staff, I encourage you to post your questions on Piazza. If you have a question that is fairly long, please come to office hours and speak to me directly.

Office Hours:
Karthik Ganapathy:
Nathan Wenger:  
XXX:
Jianxiang Tan: 

Quizzes:
There will be five quizzes in class on the following dates: January 16, January 30, February 11, February 25, March 11 . Each quiz is cumulative but the emphasis will be what was covered the previous three or four lectures leading up to it. If you miss any of the five quizzes, you can take a makeup quiz on March 13. Aside from this, no makeup quizzes will be given. Each quiz is equally weighted.

Reading Assignments:
You will be assigned sections of the textbook to read every week, and you are expected to fill a form answering some basic questions based on these readings. Each reading assignment is equally weighted.

Reflection Assignments:
There will be three reflection assignments which will be posted on Canvas. They will be due on January 18, February 15, March 11. The first reflection assignment is worth 1% of your overall grade; the second and third are worth 2.5% each.

Final Exam:
It is on March 16 from 11:30am to 2:30pm in PCYNH 106. Cheat sheet policy is TBA. No makeup exams will be given in this course.
Note: It is standard Math Department practice to utilize different versions of exams, both within each lecture's exam, and between lectures whose exams are at different times.

Regrades: Regrade requests for Quizzes and the Final may be made using the built-in regrade request feature in Gradescope. Typically, you are given one week from when the scores are released to submit regrade requests. For the Final and later quizzes, this window will be greatly shortened.

Grading Policy:

To ensure fairness and recognize different paths to success, your final grade will be calculated using the highest score from three grading rubrics: 

1. 9% Reading Assignments; 6% Reflection Assignments; 45% Final; 40% Quizzes

2. 9% Reading Assignments; 6% Reflection Assignments; 35% Final; 50% Quizzes

3. 9% Reading Assignments; 6% Reflection Assignments; 60% Final; 25% Quizzes

The first rewards students who stay consistent with quizzes and assignments, the second protects against having a single off day during finals, and the third provides an opportunity to demonstrate mastery on the final exam even if earlier work was weaker. 

The final grades will be at least as generous as the standard ones (97.00 - 100.00 A+; 94.00 - 96.99 A; 90.00 - 93.99 A-; 87.00 - 89.99 B+; 84.00 - 86.99 B; 80.00 - 83.99 B-; 77.00 - 79.99 C+; 74.00 - 76.99 C; 70.00 - 73.99 C; <70.00 F)

Attendance Policy: You are expected to attend every session of the lectures and discussion section you are enrolled in. Students who do not attend class rarely succeed in this course.  If you must miss class for any reason, it is your responsibility to catch up on the material. You are also responsible for the information given in any announcements made during class. Please note that lectures will NOT be recorded.

Academic Integrity: Academic dishonesty is considered a serious offense at UCSD. Students caught cheating will face an administrative sanction which may include suspension or expulsion from the university. Using LLMs for any assignments will be considered a form of academic dishonesty. 

Accommodations: Students requesting accommodations for this course due to a disability must provide a current Authorization for Accommodation (AFA) letter issued by the Office for Students with Disabilities (https://osd.ucsd.edu/.) Students are required to discuss accommodation arrangements with instructors and OSD liaisons in the department in advance of any exams or assignments.