Apparatus and method for reading or writing user data

An apparatus for writing user data comprising files block-wise onto a storage medium, the storage of which is divided into blocks, and for writing a plurality of keys associated with said files, comprising:

• a command interface for receiving and interpreting a write command, said write command including a user data information specifying which file of said files is to be written and a related encryption indicator indicating if said file shall be written in encrypted form or not,
• encryption means for encrypting said file using key data of said plurality of keys, and
• writing means for writing said file, said encryption indicator and, if said user data are encrypted, a key data identifier specifying which key data of said plurality of keys to use for encrypting said file, wherein the key data identifier is stored next to a block from which the user data are to be read.

A method of writing user data comprising files block-wise onto a storage medium, the storage of which is divided into blocks, and for writing a plurality of keys on said storage medium and associated with said files, said method comprising the acts of:

• receiving and interpreting a write command, said write command including a user data information specifying which of said file is to be written and a related encryption indicator indicating if said file shall be written in encrypted form or not,
• encrypting said file using key data of said plurality of keys and writing said file, said encryption indicator and, if said user data are encrypted, a key data identifier specifying which key data of said plurality of keys to use for encrypting said file, wherein the key data identifier is stored next to a block from which the user data are to be read.

A storage medium storing files in blocks and storing a plurality of keys associated with said files, said files being selectively stored in encrypted or unencrypted form, further storing in each block an encryption indicator indicating if a tile of said files stored in said block is encrypted or not and a key identifier specifying which key of the plurality of keys is used for encrypting said file if said file is encrypted, wherein the key data identifier is stored next to the block from which the user data are to be read.