Generate a bind9 rndc key (See related posts)

// description of your code here

dnssec-keygen -a hmac-md5 -b 256 -n HOST mybrandnewkey

The result will be something like "K%2Ftmp%2Fmybrandnewkey.+157+42885", so you do

cat K%2Ftmp%2Fmybrandnewkey.+157+42885.private

Put the key in /etc/rndc.key like this:

key "rndc-key" {
        algorithm hmac-md5;
        secret "Hr1U28EsMhp8r0TEEjAmksoldReEYuiWwQFH0/gkk6I=";
};