Systems and methods, including computer software adapted to perform certain operations, can be implemented for remotely defining security data for authorizing access to data on a client device. Permission indicators are associated with a sequence of instructions, and a protected activity is associated with one or more of the permission indicators and with an instruction within the sequence of instructions. The one or more permission indicators and the sequence of instructions are provided to a remote device. The remote device determines whether execution of the instruction is permitted based, at least in part, on the one or more permission indicators, and the remote device performs the protected activity if execution of the instruction is permitted.