A machine-readable storage medium comprising machine-readable instructions that, when executed by the machine, cause the machine to perform an authentication protocol comprising: generating a nonce; sending the nonce to a store (108, 108A, 108N); and receiving a session key from the store, wherein the session key is encrypted using a public key associated with the machine, which is a host (120, 120A, 120N); the machine-readable instructions further capable of performing processing comprising: accessing via the host content which has been loaded onto the store, wherein a content license is bound to the store, such that the store is permitted to interact with or performing actions on the content under the terms of said content license, and such that, if the store is afterwards removed from the host, and the store is inserted into another host, the license for the content moves with the store to the other host, and the host retains no residual rights regarding the content; and evaluating whether the store inserted into the host contains any tokens related to licensed content on the store, wherein a token comprises a content license; and if the store contains at least one token, requesting from a token granting service validation of any tokens found on the store, and if the store inserted into the host does not contain any tokens, requesting a token from the token granting service; and after validation of the token or obtaining a token, playing, by said host the licensed content using the session key. generating a nonce; sending the nonce to a store (108, 108A, 108N); and receiving a session key from the store, wherein the session key is encrypted using a public key associated with the machine, which is a host (120, 120A, 120N); the machine-readable instructions further capable of performing processing comprising: accessing via the host content which has been loaded onto the store, wherein a content license is bound to the store, such that the store is permitted to interact with or performing actions on the content under the terms of said content license, and such that, if the store is afterwards removed from the host, and the store is inserted into another host, the license for the content moves with the store to the other host, and the host retains no residual rights regarding the content; and evaluating whether the store inserted into the host contains any tokens related to licensed content on the store, wherein a token comprises a content license; and if the store contains at least one token, requesting from a token granting service validation of any tokens found on the store, and if the store inserted into the host does not contain any tokens, requesting a token from the token granting service; and after validation of the token or obtaining a token, playing, by said host the licensed content using the session key. accessing via the host content which has been loaded onto the store, wherein a content license is bound to the store, such that the store is permitted to interact with or performing actions on the content under the terms of said content license, and such that, if the store is afterwards removed from the host, and the store is inserted into another host, the license for the content moves with the store to the other host, and the host retains no residual rights regarding the content; and evaluating whether the store inserted into the host contains any tokens related to licensed content on the store, wherein a token comprises a content license; and if the store contains at least one token, requesting from a token granting service validation of any tokens found on the store, and if the store inserted into the host does not contain any tokens, requesting a token from the token granting service; and