LWDRM (Lightweight Digital Rights Management) Information Science and Technology Master 1 st Yuuki Horita

Reference  R. Grimm, P. Aichroth : Privacy Protection for Signed Media Files : A separation-of-Duty Approach to the Lightweight DRM (LWDRM) System, In proceedings of the 2004 multimedia and security workshop on Multimedia and security 

LWDRM  DRM system developed by Fraunhofer Institute in Germany content providers users

File Format  LMF (local media file) available only on the computer into which the user downloaded it  SMF (signed media file) able to distribute freely includes the user ’ s signature

LMF content providers users RSA keys created using parameters of the user ’ s hardware AES encryption RSA encryption LMF public system key private system key contents

Decode LMF private system key RSA decryption AES decryption “ private system key ” is available only on the hardware into which the contents were downloaded (binding to the hardware)

Transform LMF into SMF  Release the session key from its local binding public user key private user key

Transform LMF into SMF (cont ’ d) Certificates of public user key Signed Receipt of content purchase SMF

Decode SMF Certificates of public user key Signed Receipt of content purchase verification RSA decryption AES decryption

Features of LWDRM  Digital contents are allowed to be transferred to the other hardware  SMF includes the user ’ s signature illegal contents can be traced back certificate of public key have to be issued by specific CA

Evaluation  meets the requirements of both contents providers and consumers illegal contents can be traced back the contents can be copied to the other hardware  makes users conscious of their responsibility for the downloaded contents  seems to take a lot of time to develop the environment

“ Separation of Duty ” Principle  separate real user name and digital contents use pseudonymous consumer id instead of real user name