For as long as Python has been around, a strength has been the ecosystem of packages written not in Python, but in C -- whether that's PIL, or numpy, or simplejson, or one of the thousands of others. But why C? Why not some other language? In the last several years, Rust has emerged as a serious competitor to C. This talk will explore how we went about the process of using Rust in the pyca/cryptography package, the challenges we faced, the successes we found, and what this means for your projects.