This four-volume set LNISCT 627-630 constitutes the proceedings of the 20th EAI International Conference on Security and Privacy in Communication Networks, SecureComm 2024, held in Dubai, United Arab Emirates during October 28 - 30, 2024. The 81 full papers were carefully reviewed and selected from 225 submissions. The proceedings focus on Privacy and Cryptography AI for cybersecurity and Adversial models Quantum Computing in Cybersecurity Network Security Blockchain and Cryptocurrencies Fuzzing and IoT security Malware and Attack Analysis Web Security Authentication Large Language Model for Cybersecurity Security Assessments