By the year 2000, a balance was sought between security requirements and a respect for privacy, as well as for individual and collective freedoms. As we progress further into the 21st century, however, security is taking precedence within an increasingly controlled society. This shift is due to advances in innovative technologies and the investments made by commercial companies to drive constant technological progress. Despite the implementation of the General Data Protection Regulation (GDPR) within the EU in 2018 or 2020’s California Consumer Privacy Act (CCPA), regulatory bodies do not have the ability to fully manage the consequences presented by emerging technologies. Security and Its Challenges in the 21st Century provides students and researchers with an international legal and geopolitical analysis; it is also intended for those interested in societal development, artificial intelligence, smart cities and quantum cryptology.