AWS EFS supports stunnel-based TLS encryption for NFS mounts.

Make sure distro has efs-utils installed.

sudo yum install -y amazon-efs-utils
# OR
sudo apt-get install -y amazon-efs-utils

nfs-utils will mount drives but it will not provide encryption.

sudo yum install nfs-utils

Standard mount with TLS

sudo mkdir -p /mnt/efs 
sudo mount -t efs -o tls fs-12345678:/ /mnt/efs

Mount via /etc/fstab

fs-12345678:/ /mnt/efs efs _netdev,tls 0 0 
10.10.10.10:/ /mnt/efs efs _netdev,tls 0 0

Mount automatically

sudo mount -a

Check whether stunnel or efs-proxy is running

ps aux | grep -E "stunnel|efs-proxy"

aws-efs-utils in not avaiable on RedHat 6 & 7.