W. Shapiro and R. Vingralek. How to manage persistent state in DRM systems. In Digital Rights Management Workshop, pages 176--191, 2001.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....SSL connection deliver content Figure 5: Digital rights management with PTR architecture. Digital Rights Management (DRM) is a hot topic since the advent of large scale sharing of copyrighted media over the Internet. We are starting to see applications that attempt to enforce simple DRM policies [20]. A typical scenario is for an individual to buy a media file that can only be played once, or on a single computer. This type of policy is enforced by encrypting the the media file so that it can only be decoded by an authorized reader, which enforces the single use policy. Unfortunately, a ....

....in secure compartments, where instructions are encrypted and from which data can escape only on explicit request from the application. Even the operating system cannot violate the security model. However, XOM s integrity mechanism is vulnerable to replay attacks, which was also pointed out in [20]. In particular, XOM will not notice if writes to memory are sometimes ignored. XOM can be fixed by using memory integrity verification to protect against replay attacks. In the aegis untrusted operating system solution, we have drawn insight from XOM, notably for the on chip data tagging ....

W. Shapiro and R. Vingralek. How to Manage Persistent State in DRM Systems. In Digital Rights Management Workshop, pages 176--191, 2001.

....and play Analog Output Figure 5: Digital rights management with PTR ar chitecture. Digital lJghts Management (DRM) is a hot topic since the advent of large scale sharing of copyrighted media over the Internet. We are starting to see applications that at tempt to enforce simple DRM policies [20]. A typical sce nario is for an individual to buy a media file that can only be played once, or on a single computer. This type of policy is enforced by encrypting the the media file so that it can only be decoded by an authorized reader, which enforces the single use policy. Unfortunately, a ....

....in secure compartments, where instructions are encrypted and from which data can escape only on explicit request from the application. Even the operating system cannot violate the security model. However, XOM s integrity mechanism is vulnerable to replay attacks, which was also pointed out in [20]. In par ticular, XOM will not notice if writes to memory are sometimes ignored. XOM can be fixed by using memory integrity verification to protect against replay attacks. In the AEGIS untrusted operating system solution, we have drawn insight from XOM, notably for the on chip data tagging ....

W. Shapiro and R. Vingralek. How to Manage Persistent State in DRM Systems. In Digital Rights Management Workshop, pages 176 191, 2001.

....must be somewhere in the code, it is thus possible to recover it. If we try to develop new business models such as pay per use, running time, pay per print, we need a secure place where to store those values (number of prints, amount, Some people tried to implement it in software [SV01, VMS02] although a minimal security is di#cult to achieve. Basically, if these values are not stored in a secure hardware device, it is very easy to make a bit copy of the hard disk, use the program, replace the contents of the hard disk with the copy made. After that, the protection system is ....

W. Shapiro and R. Vingralek. How to Manage Persistent State in DRM Systems. Technical Report STAR-TR-01-06, InterTrust Starlab, 2001. 48

....stored by a program in the same compartment. XOM prevents an adversary from copying encrypted blocks from one address to another by combining the address into the hash of the data that it calculates. However, XOM s integrity mechanism is vulnerable to replay attacks, which was also pointed out in [17]. Indeed, in XOM there is no way to detect whether data in external memory is fresh or not. An adversary can do replay attacks by having the memory return stale data that was previously stored at the same address during the same execution. In particular, XOM will not notice if only the first ....

W. Shapiro and R. Vingralek. How to Manage Persistent State in DRM Systems. In Digital Rights Management Workshop, pages 176--191, 2001.

....the log N memory bandwidth overhead. The caching algorithm of Section 5 is more general in that a single hash can be used for multiple cache blocks. This scheme can potentially reduce untrusted memory size overhead and cache pollution without increasing cache block size. Shapiro and Vingralek [14] address the problem of managing persistent state in DRM systems. Because of the large overhead of computing a MAC for each memory reference, they discount the possibility of securing volatile storage. They assume that volatile memory is inside the security perimeter. In [7] allusions are made to ....

....data on disk, we assume that it took measures to check the integrity of the data. another by combining the address into the hash of the data that it calculates. 4.3. 1 Exploiting Replay Attacks However, XOM s integrity mechanism is vulnerable to replay attacks, which was also pointed out in [14]. Indeed, in XOM there is no way to detect whether data in external memory is fresh or not. An adversary can do replay attacks by having the memory return stale data that was previously stored at the same address during the same execution. In particular, XOM will not notice if only the first ....

W. Shapiro and R. Vingralek. How to Manage Persistent State in DRM Systems. In Digital Rights Management Workshop, pages 176--191, 2001.

....models ran for approximately 4 6 hours on a Sun Workstation with 8GB of memory and 1Ghz UltraSparc 3 processors. 5.1. Replay attacks on memory We were able to find an exact sequence of events that allow adversary to replay values in memory. This existence of this attack was also suggested in [7, 14, 21]. Our method also helped us find and implement a safe solution to the memory replay problem. We start by noting that [14] proposes that a hash of a memory region can be used to protect that region from replay. We model this hash by creating a second memory array that shadows the memory in the ....

W. Shapiro and R. Vingralek. How to manage persistent state in DRM systems. In Digital Rights Management Workshop, pages 176--191, 2001.

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W. Shapiro and R. Vingralek. How to manage persistent state in DRM systems. In Digital Rights Management Workshop, pages 176--191, 2001.

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W. Shapiro and R. Vingralek. How to manage persistent state in DRM systems. In Digital Rights Management Workshop, pages 176--191, 2001. 5.4.7

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W. Shapiro and R. Vingralek. How to Manage Persistent State in DRM Systems. In Digital Rights Management Workshop, pages 176--191, 2001.

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