Historically, progress in the field of cryptography has had enormous political consequences. Over the past century, for instance, cryptographic discoveries have played a key role in a world war, made it possible to use the internet for business and private communication, and raised difficult policy questions concerning the trade-off between privacy and security. In the interest of exploring the impact the field may have in the future, I consider a suite of more recent developments. My primary focus is on blockchain-based technologies (such as cryptocurrencies and smart contracts) and on privacy-preserving technologies (such as zero-knowledge proofs and secure multiparty computation). I provide a high-level introduction to these technologies that assumes no previous knowledge of cryptography. Then, I consider eight speculative predictions about the long-term consequences these emerging technologies could have. These predictions include the views that a growing number of information channels used to conduct surveillance may “go dark,” that it may become easier to verify compliance with agreements without intrusive monitoring, that the roles of a number of centralized institutions ranging from banks to voting authorities may shrink, and that new transnational institutions known as “decentralized autonomous organizations” may emerge. I close by outlining the technical and political difficulties that could prevent such predictions from being fulfilled.