Securing data is more important than ever, yet cryptographic file systems still have not received wide use. One barrier to the adoption of cryptographic file systems is that the performance impact is assumed to be too high, but in fact is largely unknown. In this paper we first survey available cryptographic file systems. Second, we perform a performance comparison of a representative set of the systems, emphasizing multiprogrammed workloads. Third, we discuss interesting and counterintuitive results. We show the overhead of cryptographic file systems can be minimal for many real-world workloads, and suggest potential improvements to existing systems. We have observed not only general trends with each of the cryptographic file systems we compared but also anomalies based on complex interactions with the operating system, disks, CPUs, and ciphers.