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

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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.