Cryptanalysis of the DECT
New cryptanalysis of the proprietrary encryption algorithm used in the Digital Enhanced Cordless Telecommunications (DECT) standard for cordless phones.
Abstract. The DECT Standard Cipher (DSC) is a proprietary 64-bit stream cipher based on irregularly clocked LFSRs and a non-linear output combiner. The cipher is meant to provide confidentiality for cordless telephony. This paper illustrates how the DSC was reverse-engineered from a hardware implementation using custom firmware and information on the structure of the cipher gathered from a patent. Beyond disclosing the DSC, the paper proposes a practical attack against DSC that recovers the secret key from 215 keystreams on a standard PC with a success rate of 50% within hours; somewhat faster when a CUDA graphics adapter is available.
Posted on April 8, 2010 at 1:05 PM • 24 Comments