FlipIt: The Game of “Stealthy Takeover”

Recent targeted attacks have increased significantly in sophistication, undermining the fundamental assumptions on which most cryptographic primitives rely for security. For instance, attackers launching an Advanced Persistent Threat (APT) can steal full cryptographic keys, violating the very secrecy of “secret” keys that cryptographers assume in designing secure protocols. In this article, we introduce a game-theoretic framework for modeling various computer security scenarios prevalent today, including targeted attacks. We are particularly interested in situations in which an attacker periodically compromises a system or critical resource completely, learns all its secret information and is not immediately detected by the system owner or defender. We propose a two-player game between an attacker and defender called FlipIt or The Game of “Stealthy Takeover.” In FlipIt, players compete to control a shared resource. Unlike most existing games, FlipIt allows players to move at any given time, taking control of the resource. The identity of the player controlling the resource, however, is not revealed until a player actually moves. To move, a player pays a certain move cost. The objective of each player is to control the resource a large fraction of time, while minimizing his total move cost. FlipIt provides a simple and elegant framework in which we can formally reason about the interaction between attackers and defenders in practical scenarios. In this article, we restrict ourselves to games in which one of the players (the defender) plays with a renewal strategy, one in which the intervals between consecutive moves are chosen independently and uniformly at random from a fixed probability distribution. We consider attacker strategies ranging in increasing sophistication from simple periodic strategies (with moves spaced at equal time intervals) to more complex adaptive strategies, in which moves are determined based on feedback received during the game. For different classes of strategies employed by the attacker, we determine strongly dominant strategies for both players (when they exist), strategies that achieve higher benefit than all other strategies in a particular class. When strongly dominant strategies do not exist, our goal is to characterize the residual game consisting of strategies that are not strongly dominated by other strategies. We also prove equivalence or strict inclusion of certain classes of strategies under different conditions. Our analysis of different FlipIt variants teaches cryptographers, system designers, and the community at large some valuable lessons:

1. Systems should be designed under the assumption of repeated total compromise, including theft of cryptographic keys. FlipIt provides guidance on how to implement a cost-effective defensive strategy.
2. Aggressive play by one player can motivate the opponent to drop out of the game (essentially not to play at all). Therefore, moving fast is a good defensive strategy, but it can only be implemented if move costs are low. We believe that virtualization has a huge potential in this respect.
3. Close monitoring of one’s resources is beneficial in detecting potential attacks faster, gaining insight into attacker’s strategies, and scheduling defensive moves more effectively.

Interestingly, FlipIt finds applications in other security realms besides modeling of targeted attacks. Examples include cryptographic key rotation, password changing policies, refreshing virtual machines, and cloud auditing.     

Biohybrid Nanostructured Iron Oxide Nanoparticles and Satureja hortensis to Prevent Fungal Biofilm Development

Cutaneous wounds are often superinfected during the healing process and this leads to prolonged convalescence and discomfort. Usage of suitable wound dressings is very important for an appropriate wound care leading to a correct healing. The aim of this study was to demonstrate the influence of a nano-coated wound dressing (WD) on Candida albicans colonization rate and biofilm formation. The modified WD was achieved by submerging the dressing pieces into a nanofluid composed of functionalized magnetite nanoparticles and Satureja hortensis (SO) essential oil (EO). Chemical composition of the EO was established by GC-MS. The fabricated nanostructure was characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Differential Thermal Analysis (DTA) and Fourier Transform-Infrared Spectroscopy (FT-IR). The analysis of the colonized surfaces using (Scanning Electron Microscopy) SEM revealed that C. albicans adherence and subsequent biofilm development are strongly inhibited on the surface of wound dressing fibers coated with the obtained nanofluid, comparing with regular uncoated materials. The results were also confirmed by the assay of the viable fungal cells embedded in the biofilm. Our data demonstrate that the obtained phytonanocoating improve the resistance of wound dressing surface to C. albicans colonization, which is often an etiological cause of local infections, impairing the appropriate wound healing.     

Polycyclic Aromatic Hydrocarbons in Romanian Baby Foods and Fruits

Levels of polycyclic aromatic hydrocarbons (PAHs) in commercially available baby food and in different sorts of fruits were investigated. PAHs determination was performed by gas chromatography coupled with mass spectrometry (GC/MS). The sum of 15 PAHs varied in baby food from 2.52–6.7 μg/kg and in fruits from 0.40–21.52 μg/kg. Benzo[a]pyrene used as a marker for PAHs contamination was detected in lower levels in baby food than the maximum tolerable limit (1 μg/kg) stated in Commission Regulation no 1881/2006.     

Protection of Historical Wood against Microbial Degradation—Selection and Application of Microbiocides

The aim of this study was to select effective and safe microbiocides for the disinfection and protection of historical wooden surfaces at the former Auschwitz II-Birkenau concentration and extermination camp. We tested seven active compounds against bacteria and moulds, of which didecyldimethylammonium chloride and N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine were effective even at 0.02%–2%. Subsequently, eight microbiocides containing the selected active ingredients were chosen and applied three times on the surface of wood samples colonized by bacteria and moulds. ABM-1 and ABM-2—6% solution; Rocima 101—8%; Preventol R 80—12%; Acticide 706 LV—15% and Boramon—30% were the most effective disinfectants. Under laboratory conditions, ABM-1, Boramon and Rocima 101 ensured antimicrobial protection of new wood samples for six months. In situ, 30% Boramon and 8% Rocima 101 applied by spraying effectively protected the historical wood from bacterial and mould growth for 12 and 3 months, respectively. Colour and luminance of the new wood were not altered after exposure to the biocides. Boramon and Rocima 101, applied by the spraying method, caused no significant change in the colour of the historical wood. Results from this study were used to develop a procedure for the protection of wood in historical buildings against biodeterioration.     

The Impact of Soy Isoflavones on MCF-7 and MDA-MB-231 Breast Cancer Cells Using a Global Metabolomic Approach

Despite substantial research, the understanding of the chemopreventive mechanisms of soy isoflavones remains challenging. Promising tools, such as metabolomics, can provide now a deeper insight into their biochemical mechanisms. The purpose of this study was to offer a comprehensive assessment of the metabolic alterations induced by genistein, daidzein and a soy seed extract on estrogen responsive (MCF-7) and estrogen non-responsive breast cancer cells (MDA-MB-231), using a global metabolomic approach. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that all test compounds induced a biphasic effect on MCF-7 cells and only a dose-dependent inhibitory effect on MDA-MB-231 cells. Proton nuclear magnetic resonance (¹H-NMR) profiling of extracellular metabolites and gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites confirmed that all test compounds shared similar metabolic mechanisms. Exposing MCF-7 cells to stimulatory concentrations of isoflavones led to increased intracellular levels of 6-phosphogluconate and ribose 5-phosphate, suggesting a possible upregulation of the pentose phosphate pathway. After exposure to inhibitory doses of isoflavones, a significant decrease in glucose uptake was observed, especially for MCF-7 cells. In MDA-MB-231 cells, the glutamine uptake was significantly restricted, leading to alterations in protein biosynthesis. Understanding the metabolomic alterations of isoflavones represents a step forward in considering soy and soy derivates as functional foods in breast cancer chemoprevention.     

Aromatic Core Extension in the Series of N‐Cyclic Bay‐Substituted Perylene G‐Quadruplex Ligands: Increased Telomere Damage,Antitumor Activity,and Strong Selectivity for Neoplastic over Healthy Cells

Based on previous work on both perylene and coronene derivatives as G‐quadruplex binders, a novel chimeric compound was designed: N,N′‐bis[2‐(1‐piperidino)‐ethyl]‐1‐(1‐piperidinyl)‐6‐[2‐(1‐piperidino)‐ethyl]‐benzo[ghi]perylene‐3,4:9,10‐tetracarboxylic diimide (EMICORON), having one piperidinyl group bound to the perylene bay area (positions 1, 12 and 6, 7 of the aromatic core), sufficient to guarantee good selectivity, and an extended aromatic core able to increase the stacking interactions with the terminal tetrad of the G‐quadruplex. The obtained “chimera” molecule, EMICORON, rapidly triggers extensive DNA damage of telomeres, associated with the delocalization of telomeric protein protection of telomeres 1 (POT1), and efficiently limits the growth of both telomerase‐positive and ‐negative tumor cells. Notably, the biological effects of EMICORON are more potent than those of the previously described perylene derivative (PPL3C), and more interestingly, EMICORON appears to be detrimental to transformed and tumor cells, while normal fibroblasts expressing telomerase remain unaffected. These results identify a new promising G‐quadruplex ligand, structurally and biologically similar on one side to coronene and on the other side to a bay‐monosubstituted perylene, that warrants further studies.     

Electrochemical activity and microscopy of electrosynthesised poly(o-phenylenediamine) nanotubes

Poly(o-phenylenediamine) (PoPD) nanotube electrodes were obtained by templated electropolymerization employing anodic porous alumina membrane. Infrared Spectroscopy measurements confirmed the polymerization of oPD into the alumina templates. The electrochemical activity of the PoPD nanotube electrodes were assessed by cyclic voltammetry (CV) as a function of monomer concentration. The morphology of the obtained nanostructures was assessed by scanning electron microscopy measurements. The results showed that poly(o-phenylenediamine) nanotube arrays have uniform diameter and they match the aspect ratio of the anodic porous membrane used for the synthesis. A high filling factor of the polymer within the alumina template was also revealed. The CV studies showed that the electrochemical properties of the PoPD nanotubes are greatly influenced by the monomer concentration in the synthesis electrolyte.     

Bifunctional Nanoscopic Catalysts for the One-Pot Synthesis of (±)-Menthol from Citral

Active and selective bifunctional Me(Ir, Pd)/beta zeolite and doped nanoscopic hydroxylated fluorides (0.1?% Pd (or Pt)/AlF₃) catalysts were developed for the one-pot synthesis of menthols from citral. In the case of fluoride catalysts, the strong electron-withdrawing effect of the dominating fluoride environment depletes the metal surface from electrons and hence, favours the hydrogenation of the C=C bond to citronellal on both Pd and Pt-based catalysts.     

PHOTOINDUCED WETTABILITY OF TITANIUM OXIDE THIN FILMS

We present here the results of a systematic investigation of the influence of the main deposition parameters (substrate temperature, deposition time, reactive gas composition, etc.) on the hydrophilic properties of DC sputtered titania films, grown on heated glass substrates (463?573 K), using water vapors as the reactive gas. Reference samples prepared in standard oxygen-based deposition conditions were used to compare the results. All the investigated samples were polycrystalline, with either pure anatase or mixed anatase-rutile nano-phase mixtures, depending on substrate temperature and film thickness. The surface wettability, evaluated from contact angle data during UV irradiation and in the back-reaction conditions, is discussed in terms of the synergic effects of materials structure, surface morphology, elemental composition, and electronic properties.