Muneeb Ali will present his FPO on Friday, May 19, 2017 at 1:30pm in CS 105. The members of his committee are: Andrea LaPaugh (adviser); Readers: Mike Freedman and Arvind Narayanan; Nonreaders: Jennifer Rexford and Brian Kernighan All are welcome to attend. The talk title and abstract follow below. Trust-to-Trust Design of a New Internet The internet’s original design, guided by the end-to-end design principle, pushed all application-specific logic and complexity to the edges of the network and kept the core of the network focused on the simple task of delivering data. The original end-to-end principle, however, did not explicitly account for trust and security. There are several central points of trust and failure on the traditional internet. These include root servers for the Domain Name System (DNS) and public-key infrastructure like Certificate Authorities (CAs) that publish security certificates. Further, the success of cloud hosted services in the last decade means that most user data is stored on remote servers and end-users need to trust these remote servers for correct execution of their applications. In this thesis, we present a new internet architecture that explicitly follows the trust-totrust design principle, i.e., end-users don’t need to trust the core of the network for anything, and end-users can use applications and services in a fully decentralized way. We make the observation that cryptocurrency blockchains, like Bitcoin, can be used to bootstrap trust for new nodes joining a network. We identify the various limitations, like high latency and limited bandwidth, of contemporary blockchains and discuss how our architecture can scale by moving most operations outside of the blockchain layer. We detail our experience of running a large production system on top of a cryptocurrency blockchain and how that experience guided our design. We present the implementation of a new decentralized internet, called Blockstack, that takes the trust-to-trust architecture from a theoretical concept to a production system. Deploying new systems by modifying production blockchains is hard because it requires coordination and agreement from several parties. We introduce virtualchains, a virtual blockchain constructed by processing data from underlying blockchains, to enable the seamless introduction of new functionality on top of blockchains without requiring any consensus-breaking changes. Blockstack is already powering several fully decentralized applications, like OpenBazaar; it’s released as open-source software and, to date, more than 70,000 domains have been registered on it.