A CIMPA research school on
Arithmetic in action:
Number Theory and its Applications to
Cryptography and Coding Theory

Gadjah Mada University
Yogyakarta, Indonesia
July 14th-25th 2025

This summer school focuses on number theory and its practical applications in cryptography and coding theory. Broadly speaking, number theory investigates properties of integers, including primes and solutions of Diophantine equations.
Despite being a very ancient branch of mathematics, number theory very much remains a dynamic branch of mathematics, with ongoing research uncovering impressive results every year, and with new puzzling questions regularly surfacing.
In recent decades, number theory has come to play a pivotal role in numerous real-life problems : for instance, prime numbers and their properties lie at the heart of the algorithms used to secure online payments. With the rapid development of computing technologies, it is actually fair to say that number theory takes a rapidly growing importance in cryptography and coding theory.
Our summer school aims to bridge theory and practice by providing students both with introductions to several key areas of number theory, and with a hands-on understanding of some of their prominent applications in cryptography and coding theory.


  • Richard Griffon (External coordinator)
    Université Clermont Auvergne

  • Uha Isnaini (Local coordinator)
    Gadjah Mada University