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Digital Rights Management:

jerome avatar
jerome
26 diapositives · 1.3K Views · Aug 18, 2012

Digital Rights Management:. The Technology behind the Hype Mark Stamp Department of Computer Science San Jose State University. This talk…. What is DRM? Overview of MediaSnap DRM system Other DRM systems Conclusions. What is DRM?. “Remote control” problem Digital book example

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  1. Digital Rights Management: The Technology behind the Hype Mark Stamp Department of Computer Science San Jose State University

  2. This talk… • What is DRM? • Overview of MediaSnap DRM system • Other DRM systems • Conclusions DRM

  3. What is DRM? • “Remote control” problem • Digital book example • Digital music, video, documents, etc. • Privacy DRM

  4. Persistent Protection • Restrictions on use afterdelivery • No copying • Limited number of reads • Time limits • No forwarding • etc. DRM

  5. What to do? • The honor system (The Plant) • Give up (HIPAA, etc.) • Lame software-based DRM • Better software-based DRM • Tamper-resistant hardware http://www.cl.cam.ac.uk/%7Erja14/tcpa-faq.html DRM

  6. The hype • “Our solutions let enterprises control their confidential information at all times, even after the recipients receive it.” --- Authentica • “Seal confidential digital documents and protect you business against intellectual property theft indefinitely.” --- SealedMedia DRM

  7. Is crypto the answer? DRM

  8. Current state of DRM • Security by obscurity (at best) • Secret designs (Kerckhoff’s Principle?) • Crypto is king • “Whoever thinks his problem can be solved using cryptography, doesn’t understand his problem and doesn’t understand cryptography.” --- Attributed by Roger Needham and Butler Lampson to each other DRM

  9. MediaSnap’s DRM system • Secure Document Server (SDS) • PDF plugin (or reader) • Security stuff… DRM

  10. Protecting a document encrypt Sender persistent protection Recipient SDS DRM

  11. Tethered mode Sender key Recipient SDS DRM

  12. Untethered mode key Sender Recipient SDS DRM

  13. Security issues • Server (SDS) • Protect keys, authentication data, etc. • Apply persistent protection • Client (Reader/PDF plugin) • Protect keys, authenticate, etc. • Enforce persistent protection DRM

  14. Document reader security Tamper-resistance Obscurity DRM

  15. Anti-debugger Tamper-resistance Encrypted code DRM

  16. Obscurity • Key management • Authentication • Caching (keys, authentication, etc.) • Encryption and “scrambling” • Key parts (data and code) • Multiple keys DRM

  17. Other MediaSnap features • Module tamper checking (hashing) • Anti-screen capture • Watermarking • “Unique-ification” DRM

  18. Other possibilities • General code obfuscation • Code “fragilization” (guards) • OS issues DRM

  19. Make fun of DRM systems • Patently obvious • Crypto claims • Sillyness • “Respect” model • MS-DRM DRM

  20. InterTrust “…a company whose business model appears to rely entirely on legal filings against Microsoft.” DRM

  21. Crypto claims Q: How does Atabok security compare to the competition? A: The majority of service providers offer the ability to encrypt at 128-bits. Atabok encrypts your content with 256-bit encryption, which is exponentially more secure. DRM

  22. Sillyness • secretSeal’s five “radical innovations” • hieroglyphic passwords • variable-length encrypted keys • morphogenetic encryption algorithm • no encryption formula in software • the use of public keys DRM

  23. The respect model Adobe eBooks --- “It is up to the implementors of PDF viewer applications to respect the intent of the document creator by restricting access to an encrypted PDF file according to passwords and permissions contained in the file.” DRM

  24. MS-DRM (version 2) • Weak proprietary block cipher (MultiSwap) used for hashing • No controlled execution • No obfuscation, etc. DRM

  25. Conclusions • Current DRM systems are weak • Ideal software-based DRM… • Individual content is non-trivial to attack • Overall system survives repeated attacks • Is this possible? DRM

  26. More info… • M. Stamp, Digital rights management: The technology behind the hype, Journal of Electronic Commerce Research, http://www.csulb.edu/web/journals/jecr/issues/20033/paper3.pdf • M. Stamp, Risks of digital rights management, Communications of the ACM, http://www.csl.sri.com/users/neumann/insiderisks.html#147 • M. Stamp, Digital rights management: For better or for worse?, ExtremeTech, http://www.extremetech.com/article2/0,3973,1051610,00.asp DRM