| 摘要 |
A memory card used to store digital content can be secured by masking files in such a way that the files are not accessible via the FAT file system supplied on the card. The masking process can include pointing the directory entries for the protected file to a dummy file, removing cluster links in the file allocation table and encrypting the headers of protected files. Once inserted, an un-masking application can temporarily un-mask the protected files and initiate playback of the digital content. The un-masking process can include restoring the FAT cluster chains, directory entries and content headers on the memory card. Once the playback is initiated, the files can be immediately re-masked to protect the card in case it is removed during playback. The masking and un-masking processes can also include encrypting and storing a serial number of the memory card onto reserved sectors to prevent unwanted copying.
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