TY - CONF AB - Side channel attacks on cryptographic systems exploit information gained from physical implementations rather than theoretical weaknesses of a scheme. In recent years, major achievements were made for the class of so called access-driven cache attacks. Such attacks exploit the leakage of the memory locations accessed by a victim process. In this paper we consider the AES block cipher and present an attack which is capable of recovering the full secret key in almost realtime for AES-128, requiring only a very limited number of observed encryptions. Unlike previous attacks, we do not require any information about the plaintext (such as its distribution, etc.). Moreover, for the first time, we also show how the plaintext can be recovered without having access to the ciphertext at all. It is the first working attack on AES implementations using compressed tables. There, no efficient techniques to identify the beginning of AES rounds is known, which is the fundamental assumption underlying previous attacks. We have a fully working implementation of our attack which is able to recover AES keys after observing as little as 100 encryptions. It works against the OpenSSL 0.9.8n implementation of AES on Linux systems. Our spy process does not require any special privileges beyond those of a standard Linux user. A contribution of probably independent interest is a denial of service attack on the task scheduler of current Linux systems (CFS), which allows one to observe (on average) every single memory access of a victim process. AU - Gullasch, David AU - Bangerter, Endre AU - Stephan Krenn ID - 2976 TI - Cache Games - Bringing Access-Based Cache Attacks on AES to Practice ER - TY - JOUR AB - The phytohormone auxin is vital to plant growth and development. A unique property of auxin among all other plant hormones is its cell-to-cell polar transport that requires activity of polarly localized PIN-FORMED (PIN) auxin efflux transporters. Despite the substantial molecular insight into the cellular PIN polarization, the mechanistic understanding for developmentally and environmentally regulated PIN polarization is scarce. The long-standing belief that auxin modulates its own transport by means of a positive feedback mechanism has inspired both experimentalists and theoreticians for more than two decades. Recently, theoretical models for auxin-dependent patterning in plants include the feedback between auxin transport and the PIN protein localization. These computer models aid to assess the complexity of plant development by testing and predicting plausible scenarios for various developmental processes that occur in planta. Although the majority of these models rely on purely heuristic principles, the most recent mechanistic models tentatively integrate biologically testable components into known cellular processes that underlie the PIN polarity regulation. The existing and emerging computational approaches to describe PIN polarization are presented and discussed in the light of recent experimental data on the PIN polar targeting. AU - Wabnik, Krzysztof T AU - Govaerts, Willy AU - Friml, Jirí AU - Kleine Vehn, Jürgen ID - 3092 IS - 8 JF - Molecular BioSystems TI - Feedback models for polarized auxin transport: An emerging trend VL - 7 ER - TY - JOUR AB - The phytohormone auxin is an important determinant of plant development. Directional auxin flow within tissues depends on polar localization of PIN auxin transporters. To explore regulation of PIN-mediated auxin transport, we screened for suppressors of PIN1 overexpression (supo) and identified an inositol polyphosphate 1-phosphatase mutant (supo1), with elevated inositol trisphosphate (InsP 3) and cytosolic Ca 2+ levels. Pharmacological and genetic increases in InsP 3 or Ca 2+ levels also suppressed the PIN1 gain-of-function phenotypes and caused defects in basal PIN localization, auxin transport and auxin-mediated development. In contrast, the reductions in InsP 3 levels and Ca 2+ signaling antagonized the effects of the supo1 mutation and disrupted preferentially apical PIN localization. InsP 3 and Ca 2+ are evolutionarily conserved second messengers involved in various cellular functions, particularly stress responses. Our findings implicate them as modifiers of cell polarity and polar auxin transport, and highlight a potential integration point through which Ca 2+ signaling-related stimuli could influence auxin-mediated development. AU - Zhang, Jing AU - Vanneste, Steffen AU - Brewer, Philip B AU - Michniewicz, Marta AU - Peter Grones AU - Kleine-Vehn, Jürgen AU - Löfke, Christian AU - Teichmann, Thomas AU - Bielach, Agnieszka AU - Cannoot, Bernard AU - Hoyerová, Klára AU - Xu Chen AU - Xue, Hong-Wei AU - Eva Benková AU - Zažímalová, Eva AU - Jirí Friml ID - 3089 IS - 6 JF - Developmental Cell TI - Inositol trisphosphate-induced ca^2+ signaling modulates auxin transport and pin polarity VL - 20 ER - TY - JOUR AB - The polarized transport of the phytohormone auxin [1], which is crucial for the regulation of different stages of plant development [2, 3], depends on the asymmetric plasma membrane distribution of the PIN-FORMED (PIN) auxin efflux carriers [4, 5]. The PIN polar localization results from clathrin-mediated endocytosis (CME) from the plasma membrane and subsequent polar recycling [6]. The Arabidopsis genome encodes two groups of dynamin-related proteins (DRPs) that show homology to mammalian dynamin - a protein required for fission of endocytic vesicles during CME [7, 8]. Here we show by coimmunoprecipitation (coIP), bimolecular fluorescence complementation (BiFC), and Förster resonance energy transfer (FRET) that members of the DRP1 group closely associate with PIN proteins at the cell plate. Localization and phenotypic analysis of novel drp1 mutants revealed a requirement for DRP1 function in correct PIN distribution and in auxin-mediated development. We propose that rapid and specific internalization of PIN proteins mediated by the DRP1 proteins and the associated CME machinery from the cell plate membranes during cytokinesis is an important mechanism for proper polar PIN positioning in interphase cells. AU - Mravec, Jozef AU - Petrášek, Jan AU - Li, Na AU - Boeren, Sjef AU - Karlova, Rumyana AU - Kitakura, Saeko AU - Pařezová, Markéta AU - Naramoto, Satoshi AU - Nodzyński, Thomasz AU - Dhonukshe, Pankaj AU - Bednarek, Sebastian Y AU - Zažímalová, Eva AU - De Vries, Sacco AU - Jirí Friml ID - 3090 IS - 12 JF - Current Biology TI - Cell plate restricted association of DRP1A and PIN proteins is required for cell polarity establishment in arabidopsis VL - 21 ER - TY - JOUR AB - Background: Whereas the majority of animals develop toward a predetermined body plan, plants show iterative growth and continually produce new organs and structures from actively dividing meristems. This raises an intriguing question: How are these newly developed organs patterned? In Arabidopsis embryos, radial symmetry is broken by the bisymmetric specification of the cotyledons in the apical domain. Subsequently, this bisymmetry is propagated to the root promeristem. Results: Here we present a mutually inhibitory feedback loop between auxin and cytokinin that sets distinct boundaries of hormonal output. Cytokinins promote the bisymmetric distribution of the PIN-FORMED (PIN) auxin efflux proteins, which channel auxin toward a central domain. High auxin promotes transcription of the cytokinin signaling inhibitor AHP6, which closes the interaction loop. This bisymmetric auxin response domain specifies the differentiation of protoxylem in a bisymmetric pattern. In embryonic roots, cytokinin is required to translate a bisymmetric auxin response in the cotyledons to a bisymmetric vascular pattern in the root promeristem. Conclusions: Our results present an interactive feedback loop between hormonal signaling and transport by which small biases in hormonal input are propagated into distinct signaling domains to specify the vascular pattern in the root meristem. It is an intriguing possibility that such a mechanism could transform radial patterns and allow continuous vascular connections between other newly emerging organs. AU - Bishopp, Anthony AU - Help, Hanna AU - El-Showk, Sedeer AU - Weijers, Dolf AU - Scheres, Ben AU - Jirí Friml AU - Eva Benková AU - Mähönen, Ari Pekka AU - Helariutta, Ykä ID - 3088 IS - 11 JF - Current Biology TI - A mutually inhibitory interaction between auxin and cytokinin specifies vascular pattern in roots VL - 21 ER -