Streamit Lisa Compact, Руководство пользователя

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Lisa Compact 84
19 Protecting device and content
19.1 Card track encryption
When you use the Lisa as a standalone player, the audio files need to be copied on the (micro) SD
memory card to be used with the device. When you copy audio files directly onto the card, anyone can
copy and later play them on their own system. The problem increases when “Store and Forward” is
used. For such an application it is required that files are placed on a web server and downloaded by the
device.
Rather than trying to prevent copying the content, the approach to address this issue with the Lisa is to
encrypt the content and make it unplayable on other devices than the Lisa.
An encryption system using Streamit’s encryption technique is depicted in the figure below. The main
idea is simple; you use a “key” to encrypt your audio files. This is called the Encryption key and is
randomly generated using the
Streamit Card and Scheduler Toolkit . The output (encrypted) files cannot
be played with conventional audio players.
The only way to play these files is with a Lisa device which contains the encryption key on-board,
loaded via the
Lisa Configuration Tool .
Important:
·
Although the mp3 format is used in our examples, Streamit’s encryption technique is independent of
the file format.
·
The encrypted filename will be the same as that of the original file, but with all lower case characters
and the file extension .enc.
·
Once the files have been encrypted, you must not modify the filename or extension of the encrypted
files anymore.
·
Encryption key(s) are generated using the Streamit Card and Scheduler Toolkit .
·
The encryption key is loaded to the Lisa device using the Lisa Configuration Tool .