Universitas Gadjah Mada, Yogyakarta, Indonesia
July 23, 2025
Lecturing Session:
The 8th day of CIMPA SCHOOL 2025 began with a lecture by Prof. Indah Emilia Wijayanti on Cryptography. She opened the session by introducing the concept of cryptographic systems and the discrete logarithm problem. The lecture continued with a detailed explanation of the ElGamal Cryptosystem, supported by clear examples. Prof. Indah then presented the Weil pairing on elliptic curves, discussing its fundamental properties and computations. She introduced several key exchange protocols, including the Elliptic Curve Diffie-Hellman Key Exchange, standard Diffie-Hellman Key Exchange, Tripartite Diffie-Hellman Key Exchange, and Bilinear Diffie-Hellman Key Exchange. The lecture concluded with an illustration of how the ElGamal Cryptosystem operates on elliptic curves.
The next session was delivered by Dr. Anna Maria Iezzi, focusing on Coding Theory. She began with Reed–Solomon codes and their construction before moving on to cyclic codes. Dr. Iezzi explained essential properties such as the number of divisors, code dimension, and generator matrices. She highlighted the bijection between cyclic codes and ideals in the quotient ring of a polynomial ring. The session ended with examples that reinforced the theoretical concepts.
Exercise Session:
The day concluded with an exercise session, during which participants continued their work on cryptography problems. The atmosphere remained productive and interactive, supported by the speaker team.