A method for controlling security during operation of a computerized device, the method comprising: enforcing a first security policy during first operational state of the computerized device, enforcement of the first security policy providing a first level access to resources within the computerized device by processes operating in the computerized device; detecting a transition operation of the computerized device that occurs during enforcement of the first security policy, the transition operation indicating that operation of the computerized device is transitioning from the first operational state to a second operational state; in response to detection of the transition operation, enforcing a second security policy corresponding to the second operational state to provide a level of access to the resources within the computerized device that corresponds to the second operational state during operation of the second operational state; characterised by wherein enforcing a first security policy during first operational state comprises enforcing a non-installation security policy during non-installation operation of the computerized device, enforcement of the non-installation security policy providing non-installation level access to resources within the computerized device by processes operating in the computerized device; wherein detecting a transition operation comprises detecting an installation operation of the computerized device that occurs during enforcement of the non-installation security policy, the installation operation indicating that at least one installation is to be performed in the computerized device; wherein enforcing a second security policy comprises, in response to detection of the installation operation, enforcing an installation security policy to provide installation level access to the resources within the computerized device during the installation operation; and in response to an end-installation event, re-enforcing the non-installation security policy. enforcing a first security policy during first operational state of the computerized device, enforcement of the first security policy providing a first level access to resources within the computerized device by processes operating in the computerized device; detecting a transition operation of the computerized device that occurs during enforcement of the first security policy, the transition operation indicating that operation of the computerized device is transitioning from the first operational state to a second operational state; in response to detection of the transition operation, enforcing a second security policy corresponding to the second operational state to provide a level of access to the resources within the computerized device that corresponds to the second operational state during operation of the second operational state; characterised by wherein enforcing a first security policy during first operational state comprises enforcing a non-installation security policy during non-installation operation of the computerized device, enforcement of the non-installation security policy providing non-installation level access to resources within the computerized device by processes operating in the computerized device; wherein detecting a transition operation comprises detecting an installation operation of the computerized device that occurs during enforcement of the non-installation security policy, the installation operation indicating that at least one installation is to be performed in the computerized device; wherein enforcing a second security policy comprises, in response to detection of the installation operation, enforcing an installation security policy to provide installation level access to the resources within the computerized device during the installation operation; and in response to an end-installation event, re-enforcing the non-installation security policy.