The prospect of a trustworthy, globally accessible open ledger holds great promise  for humanity: It enables truly non-centralized economies of every scale, as well as unmediated cooperation and global collaboration. However, engineering  such a ledger has proven to be a complex endeavor that, perhaps non-surprisingly, requires addressing an entangled set of concerns using tools developed within different disciplines: Hardware, systems, and network design; distributed computing; cryptography; programming languages; economics; sociology; law.  

This talk will overview how the framework of universally composable (UC) security can be used to untangle the various concerns and help designing open global ledgers in a modular way. Beyond providing for an overall sound design, the framework can be used as a means of communication between the different disciplines, furthering overall understanding and trust in the system. We will review some of the current work on UC analysis of global ledgers and cryptocurrencies, and point to potential new directions.