The widespread adoption of Internet of Things (IoT) devices and embedded systems has increased connectivity between devices and digital systems, enabling advancements in automation and intelligent monitoring. However, this development has introduced growing cybersecurity challenges, particularly for resource-constrained devices. These systems face multiple security risks due to limited processing power and memory, physical access to devices, and inadequate firmware update mechanisms. Common threats include physical attacks, Distributed Denial-of-Service (DDoS) attacks, exploitation of communication protocols, and firmware manipulation aimed at gaining unauthorized control of devices or using them for malicious activities. To address these challenges, modern security solutions are essential. These include lightweight cryptographic algorithms such as ASCON, hardware roots of trust, trusted execution environments such as ARM TrustZone, Secure Boot mechanisms, and secure communication protocols such as TLS 1.3 and DTLS. In conclusion, securing IoT and embedded systems requires adopting the Security by Design principle, which integrates protection into hardware components, software, and communication layers. This approach helps achieve a balance between data protection, system performance, and resource efficiency, contributing to the development of safer and more reliable digital environments.