Cryptology: Math and Codes
- Grades 2-7
Make and break secret codes in this exciting introductory cryptology course. You’ll begin with simple Caesar ciphers, learning to encrypt and decrypt messages as well as the history behind the cipher. We’ll then move through more advanced mathematical concepts to learn substitution ciphers, Vigenère ciphers, and multiplicative and affine ciphers. All of your newly acquired knowledge will be put to the test by finishing with public key cryptography and the modern-day RSA cryptosystem.
This course combines mathematics, computer science, and electrical engineering, and it’s an excellent choice for those wishing to enhance their grasp of modern cryptology concepts such as ATM cards, computer passwords, and e-commerce. Prepare to be challenged, though—many of the concepts covered in this course are often not seen until college.
Your assigned CTY instructor will be available for learning support and one-on-one review sessions for graded assessments.
The recommended length of enrollment for this course is 3 months.
Help room meeting times (optional): Thursday – 7 p.m. ET
Time Commitment: 5-8 hours per week (1 hour optional meeting, 5-7 hours independent work).
Enrollment and tuition are time-based—students may enroll in a course by selecting an open class below. Students will progress at their own pace, with guidance from instructors who strive to meet individual needs. Note: You will need to have an active CTY Account to complete registration through MyCTY.
Synchronous class meetings typically last about an hour.
Testing and Prerequisites
|Required Level||CTY-Level||Not required|
Students must achieve qualifying scores on an advanced assessment to be eligible for CTY programs. If you don’t have qualifying scores, you have several different testing options. We’ll help you find the right option for your situation.Sign up for Testing Learn More
Course PrerequisitesCryptology: Math and Codes requires:
Successful completion of Grade 4 Mathematics or equivalent
Cost and Financial Aid
- Nonrefundable Application Fee - $15 (Waived for financial aid applicants)
- Nonrefundable International Fee - $20 (outside US only)
We are committed to serving all talented youth regardless of financial circumstances. Financial assistance is available based on need.Learn More
Please acquire all course materials by the course start date. If you have questions about these materials or difficulty locating them, please contact email@example.com.
Book Title: The Cryptoclub: Using Mathematics to Make and Break Secret Codes
Authors: Janet Beissinger and Vera Pless
This course requires a computer with high-speed Internet access and an up-to-date web browser such as Chrome or Firefox. You must be able to communicate with the instructor via email. Visit the Technical Requirements and Support page for more details.
This course uses a virtual classroom for instructor-student communication. The classroom works on standard computers with the Zoom desktop client, and on tablets or handhelds that support the Zoom Mobile app. Recorded meetings can only be viewed on a computer with the Zoom desktop client installed. The Zoom desktop client and Zoom Mobile App are both free to download.
About Mathematics at CTY
Our online Mathematics courses—spanning elementary through college-level curricula—cover a wide range of topics, from algebra and geometry to chess, cryptology, and AP Calculus and are guided by expert instructors. You’ll join group sessions with classmates to ensure you stay on track with challenging course content. Whether you’re looking for pure math fun and enrichment, to move up the math ladder and advance your honors and AP (and beyond) academic standing, or to train for mathematics competitions, there’s a CTY course that’s right for you.
Join the exciting world of competitive math
Participate in the High School Math Club or enroll in 7 IP courses: Math Olympiad for Elementary School Students, Middle School Competitive Math I, Middle School Competitive Math II, Middle School Competitive Math III, Competitive Mathematics Prep, Competitive Mathematics I, Competitive Mathematics II.