Cron job to mount encrypted sparse bundle

I can run the following command in terminal to mount an encrypted sparsebundle where the bundle password is stored in the keychain.

hdiutil attach '/Volumes/Backup/Mac1.开发者_Python百科sparsebundle'

I would like to have that command run on a schedule, so I'm using CronniX to create a cron job with that command. But, when it runs at the scheduled time, nothing happens. When I check the cron daemon mail in terminal, it says the following:

hdiutil: attach failed - Authentication error

I'm assuming that it isn't able to read the password from keychain? I don't know. Hoping somebody can shed some light on things, or point me in the right direction.

Thanks

hdiutil depends on some environment variables. Check this (ENVIRONMENT section). So, probably the environment is different when you run from terminal and from cron. According to error, I think this is due to absence of com_apple_diskimages_insecureHTTP. However the same effect will give adding -insecurehttp to the arguments or specify SSL certificate with -cacert/-capath.