A method for accessing content on a device, the method comprising: separately receiving (735, 755) a media storage structure comprising at least one device-unrestricted content piece and a content key for decrypting the particular device-unrestricted content piece in the media storage structure; prior to performing any operations on the particular device-unrestricted content piece, decrypting the particular device-unrestricted content piece using the content key and discarding the content key, characterised in that the method further comprises: separately receiving a verification parameter for authenticating that a particular device-unrestricted content piece in the media storage structure is unaltered, wherein the verification parameter is signed by a source of the media storage structure; storing the verification parameter in the received media storage structure; performing a playback operation on the particular device-unrestricted content piece without using the verification parameter to authenticate the particular device-unrestricted content piece; and in order to perform a particular non-playback operation on the particular device-unrestricted content piece, authenticating the particular device-unrestricted content piece with the verification parameter, wherein authenticating the particular device-unrestricted content piece comprises verifying that the source that signed the verification parameter is an appropriate source for the device-unrestricted content piece. separately receiving (735, 755) a media storage structure comprising at least one device-unrestricted content piece and a content key for decrypting the particular device-unrestricted content piece in the media storage structure; prior to performing any operations on the particular device-unrestricted content piece, decrypting the particular device-unrestricted content piece using the content key and discarding the content key, characterised in that the method further comprises: separately receiving a verification parameter for authenticating that a particular device-unrestricted content piece in the media storage structure is unaltered, wherein the verification parameter is signed by a source of the media storage structure; storing the verification parameter in the received media storage structure; performing a playback operation on the particular device-unrestricted content piece without using the verification parameter to authenticate the particular device-unrestricted content piece; and in order to perform a particular non-playback operation on the particular device-unrestricted content piece, authenticating the particular device-unrestricted content piece with the verification parameter, wherein authenticating the particular device-unrestricted content piece comprises verifying that the source that signed the verification parameter is an appropriate source for the device-unrestricted content piece. separately receiving a verification parameter for authenticating that a particular device-unrestricted content piece in the media storage structure is unaltered, wherein the verification parameter is signed by a source of the media storage structure; storing the verification parameter in the received media storage structure; performing a playback operation on the particular device-unrestricted content piece without using the verification parameter to authenticate the particular device-unrestricted content piece; and in order to perform a particular non-playback operation on the particular device-unrestricted content piece, authenticating the particular device-unrestricted content piece with the verification parameter, wherein authenticating the particular device-unrestricted content piece comprises verifying that the source that signed the verification parameter is an appropriate source for the device-unrestricted content piece.