Encryption Algorithm
The cipher mode used for disk encryption is aes-cbc-essiv:sha256. The
      cipher generator consists of three parts: cipher-chainmode-IVmode. So here
      cipher is AES, chainmode is CBC, and IV mode is essiv:sha256.
Consult the Linux documentation for more information at:
https://wiki.archlinux.org/index.php/Disk_encryption#Ciphers_and_modes_of_operation