Patent ID: 8074078

Claim:
A method implemented using a data storage device, the data storage device being provided with a content protection key K, the method comprising: receiving, at a data storage device, a public key B generated from a private key b at a remote location, the private key b being stored at the remote location; generating, at the data storage device, a private key d and a public key D from the private key d; generating, at the data storage device, a key encryption key L from the private key d and the public key B; encrypting the content protection key K with the key encryption key L to provide a first encrypted content protection key; encrypting the content protection key K with a first password to provide a second encrypted content protection key; storing the first encrypted content protection key and the second encrypted content protection key in the data storage device; destroying the private key d and the content protection key K at the data storage device; generating, at the data storage device, a key value r and a public key Dâ€² from the key value r and the public key D; transmitting the public key Dâ€² to the remote location; receiving, at the data storage device, a public key Lâ€² generated from the private key b and the public key Dâ€² at the remote location; obtaining, at the data storage device, the key encryption key L from the inverse key value r âˆ’1 and Lâ€²; decrypting the first encrypted content protection key using L to obtain the content protection key K; decrypting content previously encrypted using the content protection key K and stored in the data storage device using the content protection key K thus obtained; encrypting the content thus decrypted using a new content protection key Kâ€²; encrypting the new content protection key Kâ€² using the key encryption key L to provide a new first encrypted content protection key; and encrypting the new content protection key Kâ€² with the first password to provide a new second encrypted content protection key.