%ADuan, Sisi%ALiu, Chao%AWang, Xin%AWu, Yusen%AXu, Shuai%AYesha, Yelena%AZhang, Haibin%Anull Ed.%D2020%I %K %MOSTI ID: 10272155 %PMedium: X %TIntrusion-Tolerant and Confidentiality-Preserving Publish/Subscribe Messaging %XWe present Chios, an intrusion-tolerant publish/subscribe system which protects against Byzantine failures. Chios is the first publish/subscribe system achieving decentralized confidentiality with fine-grained access control and strong publication order guarantees. This is in contrast to existing publish/subscribe systems achieving much weaker security and reliability properties. Chios is flexible and modular, consisting of four fully-fledged publish/subscribe configurations (each designed to meet different goals). We have deployed and evaluated our system on Amazon EC2. We compare Chios with various publish/subscribe systems. Chios is as efficient as an unreplicated, single-broker publish/subscribe implementation, only marginally slower than Kafka and Kafka with passive replication, and at least an order of magnitude faster than all Hyperledger Fabric modules and publish/subscribe systems using Fabric. Country unknown/Code not availablehttps://doi.org/10.1109/SRDS51746.2020.00039OSTI-MSA