# three uuids and take their sum. The sum is encoded in ASCII hex, hence the
    # 64 character cut.
    out+="$(
     (
       uuidgen --random;
       uuidgen --random;
       uuidgen --random;
     ) | sha256sum \
       | head -c 64
    )";
  done
  # Finally, convert the ASCII hex to base64 to increase the density.
  echo -n "${out}" | xxd -r -p | base64 -w 0
}