This week, Facebook released Conceal, an efficient encryption library for data storage on Android. There have been concerns about Android's security for years, and Conceal aims to address the problem of publicly-accessible data on SD cards by preventing it from being accessed by other apps. According to this overview of Conceal's purpose and features from Subodh Iyengar, software engineer at Facebook, Conceal is:
...a set of Java APIs to perform cryptography on Android and make storage more secure and lightweight. We created Conceal to be small and faster than existing Java crypto libraries on Android while using memory responsibly.
Iyengar also describes the practicality and ease-of-use that set Conceal apart:
Conceal is not a general purpose crypto library. Unlike other libraries, which provide a wide range of encryption algorithms and options, Conceal prefers to abstract this choice and include sensible defaults. We think this makes sense because encryption can be very tricky to get right.
Conceal's website provides some extra details, such as benchmarks against Java and Bouncycastle for reading and writing encrypted data. Check out Iyengar's full overview and Conceal's GitHub to take a look.