This project considers models for secure collaboration and contracts in a decentralized environment among parties that have not established trust. A significant example of this is blockchain programming, with platforms such as Ethereum and HyperLedger. There are many documented defects in secure collaboration mechanisms, and some have been exploited to steal money.  Our approach builds two kinds of models to address these defects: typestate models to mitigate re-entrancy-related vulnerabilities, and linear types to model and statically detect an important class of errors involving money and other transferrable resources.

The project research will include both technical and usability assessment of these two ideas. The technical assessment addresses the feasibility of sound and composable static analyses to support these two semantic innovations. The usability assessment focuses on the ability of programmers to use Obsidian effectively to write secure programs with little training.  A combined assessment would focus on whether programmers are more likely to write correct, safe code with Obsidian than with Solidity, and with comparable or improved productivity.