Breaking DVB-CSA

Erik Tews, Julian Wälde, Michael Weiner

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

    4 Citations (Scopus)
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    Digital Video Broadcasting (DVB) is a set of standards for digital television. DVB supports the encryption of a transmission using the Common Scrambling Algorithm (DVB-CSA). This is commonly used for PayTV or for other conditional access scenarios. While DVB-CSA support 64 bit keys, many stations use only 48 bits of entropy for the key and 16 bits are used as a checksum. In this paper, we outline a time-memory-tradeoff attack against DVB-CSA, using 48 bit keys. The attack can be used to decrypt major parts a DVB-CSA encrypted transmission online with a few seconds delay at very moderate costs. We first propose a method to identify plaintexts in an encrypted transmission and then use a precomputed rainbow table to recover the corresponding keys. The attack can be executed on a standard PC, and the precomputations can be accelerated using GPUs. We also propose countermeasures that prevent the attack and can be deployed without having to alter the receiver hardware.
    Original languageEnglish
    Title of host publicationResearch in Cryptology
    Subtitle of host publication4th Western European Workshop, WEWoRC 2011, Weimar, Germany, July 20-22, 2011, Revised Selected Papers
    EditorsFrederik Armknecht, Stefan Lucks
    Number of pages17
    ISBN (Electronic)978-3-642-34159-5
    ISBN (Print)978-3-642-34158-8
    Publication statusPublished - 2011
    Event4th Western European Workshop 2011 - Weimar, Germany
    Duration: 20 Jul 201122 Jul 2011
    Conference number: 4

    Publication series

    NameLecture Notes in Computer Science


    Conference4th Western European Workshop 2011
    Abbreviated titleWEWoRC 2011


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