Cryptocurrency exchanges enable their customers to invest in cryptocurrencies. In the past, exchanges have become insolvent due to hacking or exit scams. Proof of solvency protocols prove that an exchange owns enough coins to cover its liabilities to its customers. A proof of solvency has two components: a proof of reserves protocol and a proof of liabilities protocol. In this project, we developed privacy-enhancing proof of reserves protocols for Monero, MimbleWimble, and QuisQuis. Ongoing work aims to develop protocols with logarithmic verification times using SNARKs and STARKs.