Improved cryptanalysis of the DECT standard cipher

The DECT Standard Cipher (DSC) is a 64-bit key stream cipher used in the Digital Enhanced Cordless Telecommunications (DECT) standard to protect the confidentiality of the communications. In this paper we present an improved cryptanalysis of DSC that is more effective than the prior best known one introduced by Nothl-Tews-Weinmann (NTW). Our known plaintext attack requires less than 2.8 minutes of voice communication (2^14 keystreams) compared to the more than 11 minutes (2^16 keystreams) of the NTW attack in order to retrieve the key with an equivalent success rate. Our attack yields similar improvements using control data encrypted with the first 9 bits of the keystream, instead of voice, reaching a success rate of 50% by analysing 2^13 keystreams in comparison with the 2^15 keystreams required by the NTW attack to achieve equivalent results. We have successfully applied our attack in a controlled environment against actual DECT communications. Furthermore, we have tuned our attack to work more effectively when the knowledge of plaintext is not 100% accurate. On the basis of these results, we think that the most appropriate measure to secure the privacy of DECT voice communications is the effective roll-out of the DSC-2 cipher in DECT equipment.

COISEL Iwen;  SANCHEZ MARTIN Jose Ignacio; 

2017-01-09

SPRINGER SCIENCE + BUSINESS MEDIA

JRC100662

2190-8508,   

http://link.springer.com/article/10.1007/s13389-016-0127-4,    https://publications.jrc.ec.europa.eu/repository/handle/JRC100662,   

10.1007/s13389-016-0127-4,