Coretex is a series of programming competitions organized by Core in Argentina. Related to the competition we have also organized a problem solving workshop and an exploit writing course.
The first editions of the competition (Coretex0, Coretex1, Coretex2) consisted in two phases: a "construction" phase where participants are required to write C/C++ code to solve the given problems, and a "deconstruction" phase where participants can see the source codes sent by all participants, and try to find test cases (inputs) that will make the programs fail.
The scoring system for this second phase was designed to give points to test cases that show an error or a limitation in other participant solutions or are so complex that they have bigger probabilities of making many solutions fail.
With Coretex3 we changed the dynamics of the competition. This time the programs were provided by the organizers, and the participants were asked to "exploit" them. In the context of this competition, to "exploit" a program means finding a test case that causes the program to output "exploited!" on stdout. The winners of this competition were invited to an exploit writing course given by Core Security.
Coretex6 marked a return to the construction / deconstruction dynamics with two problems that required participants to write a C/C++ program.