A method, at a media playback application , the method comprising: establishing a secure channel with a downstream component that resides downstream of the application in a chain of components that process media content that is to be rendered on a device , wherein establishing the secure channel with the downstream component comprises retrieving a public key associated with the downstream component and sending, to the downstream component, encrypted data, wherein the data has been encrypted using the public key associated with the downstream component and comprises: a random number provided by the downstream component; a data integrity session key; and a starting status sequence number and a starting command sequence number; using the secure channel to send a command message to the downstream component, the command message comprising a data section that contains a command, and an authentication section that contains data that has been processed using the data integrity session key, wherein the command message contains a command instructing the downstream component to enable one or more of a number of different types of content protection technologies to protect media content that is provided over a physical connector; using the secure channel to request status information from the downstream component; and using the secure channel to receive a status message from the downstream component, the status message comprising a data section that contains status information, and an authentication section that contains data that has been processed using the data integrity session key. establishing a secure channel with a downstream component that resides downstream of the application in a chain of components that process media content that is to be rendered on a device , wherein establishing the secure channel with the downstream component comprises retrieving a public key associated with the downstream component and sending, to the downstream component, encrypted data, wherein the data has been encrypted using the public key associated with the downstream component and comprises: a random number provided by the downstream component; a data integrity session key; and a starting status sequence number and a starting command sequence number; a random number provided by the downstream component; a data integrity session key; and a starting status sequence number and a starting command sequence number; using the secure channel to send a command message to the downstream component, the command message comprising a data section that contains a command, and an authentication section that contains data that has been processed using the data integrity session key, wherein the command message contains a command instructing the downstream component to enable one or more of a number of different types of content protection technologies to protect media content that is provided over a physical connector; using the secure channel to request status information from the downstream component; and using the secure channel to receive a status message from the downstream component, the status message comprising a data section that contains status information, and an authentication section that contains data that has been processed using the data integrity session key. <EOS>