Pourmajidi, WilliamZhang, LeiSteinbacher, JohnErwin, TonyMiranskyy, Andriy2025-04-232025-04-232019-05Pourmajidi, William, Lei Zhang, John Steinbacher, Tony Erwin, and Andriy Miranskyy. “Immutable Log Storage as a Service.” In 2019 IEEE/ACM 41st International Conference on Software Engineering: Companion Proceedings (ICSE-Companion), 280–81, 2019. https://doi.org/10.1109/ICSE-Companion.2019.00114.https://doi.org/10.1109/ICSE-Companion.2019.00114http://hdl.handle.net/11603/38076 2019 IEEE/ACM 41st International Conference on Software Engineering: Companion Proceedings (ICSE-Companion)Logs contain critical information about the quality of the rendered services on the Cloud and can be used as digital evidence. Hence, we argue that the critical nature of logs calls for immutability and verification mechanism without a presence of a single trusted party. In this paper, we propose a blockchain-based log system, called Logchain, which can be integrated with existing private and public blockchains. To validate the mechanism, we create Logchain as a Service (LCaaS) by integrating it with Ethereum public blockchain network. We show that the solution is scalable (being able to process 100 log files per second) and fast (being able to "seal" a log file in 23 seconds, on average).3 pagesen-US© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Blockchain, Hierarchical Ledger, bitcoin, privacy, log systems, Cloud log systems Log tampering, Log storage, EthereumText