CS-458: Introduction to Cryptography (Fall 2025)

This course introduces the fundamental concepts of cryptography, focusing on the cryptographic primitives used in modern security mechanisms and protocols embedded in widely used applications, such as web communications, messaging, and data storage. The topics covered include classical cryptosystems, symmetric key cryptosystems (e.g., DES, 3DES, AES), and public key cryptosystems (e.g., RSA, Diffie-Hellman, DSA, ECC). Additionally, hashing algorithms like SHA-1, SHA-2, and SHA-3 are discussed. Students will explore the security requirements of various applications and how cryptographic primitives can be effectively applied to meet these needs. The course also emphasizes common cryptographic failures, such as poor implementation or configuration, and highlights different types of cryptographic attacks. The course concludes with an introduction to quantum-resilient cryptography, post-quantum cryptography and quantum key distribution.

Learning Objectives

• Knowledge: Upon completing the course, the student will be able to clearly describe the field of cryptography and its integral role in maintaining security within various applications and systems.
• Understanding: After successfully completing the course, the student will be able to explain the different types of cryptographic primitives, understand their specific applications, and demonstrate their correct usage.
• Application: Upon course completion, the student will be able to develop and implement applications that effectively employ cryptographic primitives, adhering to security best practices.
• Analysis: The student will be able to analyze and attempt cryptanalysis of systems that utilize cryptographic primitives, identifying potential vulnerabilities or weaknesses.
• Synthesis: By the end of the course, the student will be able to integrate various cryptographic primitives to design and implement complex interactions, such as secure communication protocols.
• Evaluation: The student will be able to critically assess the strength and resilience of systems that employ cryptographic primitives, including both classical, symmetric, and public-key cryptography methods.

The final grade is calculated as follows:

• 30% Project:
• 70% Written exams (best case):
  • 30% midterm x2 (equally weighted)
  • 40% final (must be >= 4)
• BONUS: 5% Capture-the-Flag (CTF) competition

Instructor: Dr. Harry Manifavas

Lectures: Mon, Fri 11:15 - 13:00

Lectures/Lab: Wed 11:15 - 13:00 (You will be notified via email)

Location: A.125

Course Area: Software Systems and Applications (E5)

Course Credits: 6 ECTS

Prerequisites:

• CS-118: Discrete Mathematics
• CS-240: Data Structures

Suggested:

• CS-345: Operating Systems

Related courses:

• CS-455: Cybersecurity Lab
• CS-457: Introduction to Information Security Systems
• CS-457-1: Digital Forensics

This course was taught again in:

• 2022
• 2023
• 2024

Course staff	Email	Office	Office Hours
Instructor: Dr. Harry Manifavas	harryman [at] ics.forth.gr	TBA	TBA
Teaching Assistant: Giannis Vlachogiannakis	gvlach [at] csd.uoc.gr	B210	TBA
Teaching Assistant: Tsagkarakis Pantelis	csd5075 [at] csd.uoc.gr	B210	TBA