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 onPrivacy and CryptographyAI for cybersecurity and Adversial modelsQuantum Computing in CybersecurityNetwork SecurityBlockchain and CryptocurrenciesFuzzing and IoT securityMalware and Attack AnalysisWeb SecurityAuthenticationLarge Language Model for CybersecuritySecurity Assessments