Hey Chris,
Consider this comment a bump because I'm also searching for a better way. In the past I've run into problems in my environment where the JSS was reporting packages were cached on clients when in fact they were incomplete/corrupt. I came up with the following fix which worked well enough for us in the past.
It's very important to note my cached packages were installed by scripts called by Self Service policies by choice.

Here's an example package install workflow:
Self Service policy called some Install_Some_App_Checksum.sh script to run the check to be sure the cached package file size met a predetermined minimum. The package was removed and re-cached if it didn't meet the minimum file size by another script and policy in the JSS... Below is an excerpt from one of my Install_Some_App_Checksum.sh scripts...

SIZE=$(du -s /Library/Application Support/JAMF/Waiting Room/Some_App.pkg | awk '{ print $1 }')



if ((SIZE<273054)); then 

    rm -rf /Library/Application Support/JAMF/Waiting Room/Some_App.pkg; 

    rm -rf /Library/Application Support/JAMF/Waiting Room/Some_App.pkg.xml; 

    sudo /Library/Application Support/JAMF/Waiting Room/Some_App-cache_again.sh;



else 



    sudo /Library/Application Support/JAMF/Waiting Room/install_Some_App_package.sh



fi



exit 0

Best of luck and hopefully someone out there will chime in with an easier way to achieve the same result.
-Lionel

Hi Chris,

The ability to verify a package downloaded by the MD5 checksum is a new feature in version 9.3. This can be found under Settings > Computer Management > Security. For more information, refer to pages 102-103 in the 9.3 Casper Suite Administrator's Guide.

Matt

Thanks Matt,

Our rep pointed us in the same direction. Just waiting for the FileVault 2 Site Admin bug to be fixed then i will go through the upgrade.

Though this may be worth it on it's own merit.

Chris