RTOS/LAUNCHCC3220MODASF: Simplelink OTA update problem

Part Number:LAUNCHCC3220MODASF

Tool/software: TI-RTOS

Hi,

I need "DigCert_High_Assurance_CA.der"  file for using OTA example with dropbox v2 api but cannot find it on the internet or in the sdk cetificate playground files. Where can i find it? 

Thanks.