OpenJudge Alliance

The OpenJudge Alliance is an open community dedicated to the technical aspects of online educational systems and their applications in IT/CS curriculums. We promote the exchange of cutting-edge technology, reliable courseware solutions, and innovative ideas among IT/CS related educational institutions. Our community members (current + prospect) include organizers of programing contests (i.e. ACM/ICPC, OI, ...), lecturers of programming curriculums (i.e. data structures, algorithm design, ...), developers of online judge and courseware systems, etc.

For questions and/or suggestions, feel free to send email to <contact [at]>

  • [2013/05/10] Release of libsandbox 0.3.5-3

The 0.3.5-3 release of libsandbox comes with several improvements and fixes. We improved error differentiation in memory dump so that user-defined policies can fail gracefully when trying to inspect bad addresses for syscall arguments. The termination of tasks invoking restricted functions has been strengthened to avoid failures due-to unexpected overrun. We also resolved a defect in the profiling process, which may cause incomplete statistics for very short tasks... [read more]

  • [2013/03/26] Release of libsandbox 0.3.5-2

We are proud to announce the latest 0.3.5-2 release of the sandbox libraries. This new release addresses our continued effort to improve the quality of libsandbox. We refactored concurrency control in the core library. The primary data structure is now protected with read-write lock instead of bare mutex. Internally, a new trace pool is introduced to coordinate the profiling of sandbox instances. And the number of per-sandbox monitor threads has thus been reduced ... [read more]

  • [2012/08/06] New and noteworthy 0.3.4-3 release of libsandbox

For the past several weeks, we have made efforts to enhance the overall quality of the sandbox libraries; and we are happy to announce some notable results coming with the new and noteworthy 0.3.4-3 release. The core library undergone a refactor in its monitoring threads. We have merged all resource profiling jobs into the profiler thread ... [read more]

  • [2012/06/08] Release of libsandbox 0.3.4-1

We are happy to announce the latest feature upgrades of the sandbox libraries. The 0.3.4-1 release of the sandbox libraries comes with three-fold improvements. First, the core library provides a new development header <sandbox-dev.h> with macros and routines for accessing ... [read more]

  • [2012/01/13] Source code release of new libsandbox (0.3.x)

We are pleased to announce the source code release of the new 0.3.x branch of sandbox libraries. During the eight weeks of community review, we have made a number of improvements and fixes to the core library, the Pythonic binding, as well as the sample script of the libraries ... [read more]

  • [2011/12/12] HUSTOJ security risks upgraded

It has been validated that C++ solution program can also bypass some security restrictions of HUSTOJ due to the security issues previously reported in OnlineJudge Alliance technical report TR-OJA-201112A. We have updated the report and encourage all HUSTOJ hosts to follow the updated recommendations to avoid threats from malicious C++ solution programs ... [read more]

  • [2011/12/09] Technical report: security holes discovered in HUSTOJ

The OpenJudge Alliance has recently conducted a security assessment of the open-source online judge system HUSTOJ ( The result is disappointing as we discovered a series of design pitfalls and defects in the judge_client core component ... [read more]