isomd5sum software package provides ISO9660 checksum utilities, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install isomd5sum
isomd5sum is installed in your system.
Make ensure the isomd5sum package were installed using the commands given below,
$ sudo dpkg-query -l | grep isomd5sum *
You will get with isomd5sum package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Miscellaneous |
| Package | isomd5sum |
| Version | 1:1.1.0-1+b1 |
| Description | ISO9660 checksum utilities |
| Sub Section | Miscellaneous |