fscrypt is a library which filesystems can hook into to support transparent encryption of files and directories.^[1]

FSCRYPT wont be using Intel's QuickAssist Technology accelerators (QAT) anymore as it was showed to be slower than even non AVX512 accelerated code!(nice catch by Google engineer Eric Biggers) (bench in source) The same problem exist on the ARM side with Qualcomm's Crypto Engine which doesn't perform well. The way these tech work is by sending an order to en/decrypt the data to another chip in the CPU (asynchronous). The drivers tend to be buggy and the overhead of pushing the order to the other chip makes the process not worth it.^[2]