摘要 |
A method for the storage of a content from a source device to a storage device, the devices implementing a content protection protocol comprising a phase of exchanging a first encryption key (Kc) associated with a first key computation parameter (Nc). A storage method of this kind comprises the following steps; the obtaining ( 802 ) of a first processing function (m 1 ) that is a function of a predetermined piece of information for access to the content to be stored (CPK); the obtaining ( 805 ) of a second key computation parameter (Ncpk; Ncm) in taking account of said first processing function; the computation ( 806 ) of a second encryption key (Kcpk), in taking account of said second key computation parameter (Ncpk; Ncm); the encryption ( 810 ) of the content to be stored with said second key (Kcpk), thus obtaining a first encrypted content (Msa 0 ), and then the encryption ( 811 ) of the first encrypted content (Msa 0 ) with the first key (Kc), thus obtaining a second encryption content (Msa); the sending ( 812 ) of the second encrypted key (Msa) to the storage device; and the storing ( 808 ) of at least one piece of computation data (Ncm; Nc) necessary for the computation of said second parameter (Ncpk; Ncm).
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