The Platform Security was introduced from Symbian V9.0, this means proividing security to the user data and software, hardware of the machine by restricted / controlled access to them.

So the Symbian Developers requires some privileges to access the platform for their applications developed for the S60 3rd Edition (or UIQ3) devices. These privileges are name Capabilities. These capabilities are defined for signed applications, because certain APIs are restricted to use unless the capability is granted before the application uses the feature.

The Three broad Capabilities are 1) TCB 2) USER 3) System Capability

TCB : "Trusted computing Base "

The components with these capability have access to sensible system features, like private directories on the file systems. These capabilities are generally not granted to third party applications and requires an agreement with the phone or platform manufacturer to have them.

The TCB includes Operating System kernel,file server ,MMU etc.

User

NetworkServices: dialing a number or sending a text message and accessing the remote services.

LocalServices: This capability is for sending or receiving information through USB, IR, and point-to-point Bluetooth profiles.

ReadUserData : Grants read access to user data. System servers and application engines are free to grant this restriction level to their data.

WriteUserData : Grants write access to user data. Again, system servers and application engines are free to grant this restriction level to their data.

Location : Grants access to the location of the phone.

UserEnvironment: Grants access to live confidential information about the user and his/her immediate environment.

System Cabability:

These API's under these capbilities has access to sensitive parts of the machine which due programatical errors may corrupt the phone's Software and hardware. So these capabilities are granted only after symbian signed which after testing is done.

ALLFiles,SwEvent,WriteDeviceData,PowerMgmt,Drm, etc.

How to assign capabilities:

The capabilites are assigned in MMP file using CAPABILITY keyword.

CAPABILITY  ReadUserData   DiskAdmin

or

CAPABILITY   ALL -ALLFiles  Drm

it means all capabilites are included except AllFiles and Drm

Depending on our application and depending on what are the API's we are using in our application demands the capabilities required in our Project .

for E.g: DataFileSave() requires capability WriteDeviceData and WriteUserData