Google unveils new Adiantum storage encryption method for devices without cryptographic acceleration and running Android 9 or later on processors which do not support AES or other crypto instructions. Currently, users can encrypt their Android devices using Advanced Encryption Standard (AES) which is very fast on newer processors via the ARMv8 Cryptography Extensions. On an ARM Cortex-A7 processor, the new method decrypts 4096-byte messages at 10.6 cycles per byte, over five times faster than AES-256-XTS.
Source: https://www.bleepingcomputer.com/news/google/google-introduces-adiantum-storage-encryption-to-low-end-android-devices/