Papers by Konstantinos Kokordelis
arXiv (Cornell University), Oct 21, 2011
Byzantine Fault Tolerant (BFT) systems are considered by the systems research community to be sta... more Byzantine Fault Tolerant (BFT) systems are considered by the systems research community to be state of the art with regards to providing reliability in distributed systems. BFT systems provide safety and liveness guarantees with reasonable assumptions, amongst a set of nodes where at most f nodes display arbitrarily incorrect behaviors, known as Byzantine faults. Despite this, BFT systems are still rarely used in practice. In this paper we describe our experience, from an application developer's perspective, trying to leverage the publicly available and highly-tuned "PBFT" middleware (by Castro and Liskov), to provide provable reliability guarantees for an electronic voting application with high security and robustness needs. The PBFT middleware has been the focus of most BFT research efforts over the past twelve years; all direct descendent systems depend on its initial code base. We describe several obstacles we encountered and drawbacks we identified in the PBFT approach. These include some that we tackled, such as lack of support for dynamic client management and leaving state management completely up to the application. Others still remaining include the lack of robust handling of non-determinism, lack of support for web-based applications, lack of support for stronger cryptographic primitives, and others. We find that, while many of the obstacles could be overcome with a revised BFT middleware implementation that is tuned specifically for the needs of the particular application, they require significant engineering effort and time and their performance implications for the end-application are unclear. An application developer is thus unlikely to be willing to invest the time and effort to do so to leverage the BFT approach. We conclude that the research community needs to focus on the usability of BFT algorithms for real world applications, from the end-developer perspective, in addition to continuing to [Copyright notice will appear here once 'preprint' option is removed.] improve the BFT middleware performance, robustness and deployment layouts.
Abstract. Byzantine Fault Tolerant (BFT) systems are considered to be state of the art with regar... more Abstract. Byzantine Fault Tolerant (BFT) systems are considered to be state of the art with regards to providing reliability in distributed systems. Despite over a decade of research, however, BFT systems are rarely used in practice. In this paper, we describe our experience, from an application developer's perspective, trying to leverage the publicly available, highly-studied and extended "PBFT" middleware (by Castro and Liskov), to provide provable reliability guarantees for an electronic voting application with high security and robustness needs. We describe several obstacles we encountered and drawbacks we identified in the PBFT approach. These include some that we tackled, such as lack of support for dynamic client management and leaving state management completely up to the application. Others still remaining include the lack of robust handling of non-determinism, lack of support for webbased applications, lack of support for stronger cryptographic primitives, a...
Lecture Notes in Computer Science, 2012
Byzantine Fault Tolerant (BFT) systems are considered to be state of the art with regards to prov... more Byzantine Fault Tolerant (BFT) systems are considered to be state of the art with regards to providing reliability in distributed systems. Despite over a decade of research, however, BFT systems are rarely used in practice. In this paper, we describe our experience, from an application developer's perspective, trying to leverage the publicly available, highly-studied and extended "PBFT" middleware (by Castro and Liskov), to provide provable reliability guarantees for an electronic voting application with high security and robustness needs. We describe several obstacles we encountered and drawbacks we identified in the PBFT approach. These include some that we tackled, such as lack of support for dynamic client management and leaving state management completely up to the application. Others still remaining include the lack of robust handling of non-determinism, lack of support for webbased applications, lack of support for stronger cryptographic primitives, and more. We find that, while many of the obstacles could be overcome, they require significant engineering effort and time and their performance implications for the end-application are unclear. An application developer is thus unlikely to be willing to invest the time and effort to do so to leverage the BFT approach.
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Papers by Konstantinos Kokordelis