About the Course


  • Grades 7-11
  • Advanced CTY-Level

Cryptology is the study of the codes and ciphers used to create secret writing. This math course explores many early techniques in cryptology, such as cipher wheels, the Caesar shift, polyalphabetic substitution, and the Vigenère cipher, as well as modern techniques like RSA public key cryptography. You and your classmates will learn how data transmitted by computers can be secured with digital encryption, and how the vulnerabilities of each encryption system enable hackers to attack and decrypt messages using techniques such as frequency analysis and cribbing. You’ll apply concepts while encrypting and decrypting your own secret messages. Though the course’s central focus is on the mathematics of cryptology, you’ll also learn the historical context of cryptography and cryptographic devices like the Enigma Machine—one of the most important cryptographic devices in history—so you develop a deep understanding of this branch of mathematics and its applications in the world.

Typical Class Size: 16

Testing and Prerequisites

  Math Verbal
Required Level Advanced CTY-Level Not required
Check your eligibility using existing test scores If you do not have existing test scores:

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.

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Cost and Financial Aid

  • Tuition
    • Varies
  • Application fee
    • Nonrefundable Application Fee - $50 (Waived for financial aid applicants)
    • Nonrefundable International Fee - $250 (outside US only)

Financial Aid is available

We are committed to serving all talented youth regardless of financial circumstances. Financial assistance is available based on need.

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Course Materials

Students should bring basic school supplies like pens, notebooks, and folders to their summer program. You will be notified of any additional items needed before the course begins. All other materials will be provided by CTY.

Sample Reading

These titles have been featured in past sessions of the course, and may be included this summer. CTY provides students with all texts; no purchase is required.

  • The Code Book, Simon Singh

About Mathematics at CTY

Explore the study of shapes

Geometry courses allow students to describe the world around them in basic and profound ways. Our younger students learn about shape, scale, and proportion in Geometry and Spatial Sense. Middle School students explore beautiful applications of lines, angles, non-Euclidean geometry, and more in Geometry through Art. And advanced students explore the underlying mathematics and fundamental characteristics of shapes, distance, and continuous deformations in our proof-based Topology course.

Dive deep into logic and reasoning

Our courses in formal logic give you the tools to question the world around you. Younger students are introduced to different types of reasoning, as well as the strengths and weaknesses inherent in various forms of critical analysis in Inductive and Deductive Reasoning. Older students explore how logical reasoning can explain (or fail to explain) counter-intuitive results in Paradoxes and Infinities, or take a more rigorous approach to formal logic in Mathematical Logic.

Meet our instructors and staff