DSC - Reverse Engineering of the Samsung DECT SP-R6150

Ralf-Philipp Weinmann ralf at coderpunks.org
Mon Jan 26 12:29:23 CET 2009


On Jan 26, 2009, at 12:06 , Dimi Ortega wrote:

> They talked on chaos radio it will be maybe only a matter of one  
> night work to fully reverse the DSC.

The necessary work has been done now. Since I screwed up the first  
time however (I had accidentially reversed the byte order of the key/ 
IV bytes and therefore obtained an incorrect filter function), I'd  
rather verify it again before releasing it.

> But if this was alkready done in 2002 that would be crazy!
> @dedected is the 2002 reverse DSC code already known to you?

Yes. It's crap. It is _NOT_ the DECT standard cipher. The DSC is LFSR- 
based as can be seen from [1].

I think (I'm not sure though) I've briefly mentioned that Usenet  
posting in our talk @25C3, I'm sure I've mentioned it in the CRE102  
interview.

Cheers,
Ralf

[1] Manuel J. Alvarez Alvarez: Data ciphering device
     US Patent 5608802, filed Dec 27th, 1994, issued Mar 4, 1997
     http://www.google.com/patents?id=hM8dAAAAEBAJ



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