Ransomware and reputation

open access articleRansomware is a particular form of cyber-attack in which a victim loses access to either his electronic device or files unless he pays a ransom to criminals. A criminal’s ability to make money from ransomware critically depends on victims believing that the criminal will honour ransom payments. In this paper we explore the extent to which a criminal can build trust through reputation. We demonstrate that there are situations in which it is optimal for the criminal to always return the files and situations in which it is not. We argue that the ability to build reputation will depend on how victims distinguish between different ransomware strands. If ransomware is to survive as a long term revenue source for criminals then they need to find ways of building a good reputation

Validation of the Multidimensional Scale of Perceived Social Support (MSPSS) for family carers of people with dementia

Aims: The Multidimensional Scale of Perceived Social Support (MSPSS; Zimet et al., 1988) is a measure of the perceived adequacy of social support. Whilst this is an incredibly important area of research for family caregivers of people with dementia, it is not clear whether the MSPSS retains its psychometric properties when used with this population. The primary aim was to conduct an in-depth psychometric analysis of the MSPSS in a sample of family caregivers. / Method: A validation study, looking at reliability and validity of the MSPSS. Participants completed measures electronically using a self-complete procedure. Properties assessed were internal consistency, floor and ceiling effects, test-retest reliability, convergent validity and factor structure. / Results: 270 participants completed the study and 58 comprised the test-retest sample. Internal consistency was excellent for the total score (alpha = 0.92) and three subscales (alpha = 0.92-0.94). Significant correlations were observed in the expected directions with depression (r = -.48, p < .001) and mental (r = 0.32, p<.001) and physical (r = 0.17, p=.003) health-related quality of life. Test re-test reliability over a 4-week period was excellent for the total score (ICC = 0.90 95%CI = 0.84, 0.94) and subscale scores (ICC = 0.84-0.89). Confirmatory factor analysis indicated acceptable fit indices for the three-factor solution. / Conclusions: The MSPSS has robust psychometric properties and is suitable for use with family caregivers of people with dementia. The MSPSS may therefore be recommended for use with this population. Further research is required to establish responsiveness and determine cross-cultural validity

Threshold public good games and impulse balance theory

We propose and develop a model of behavior in threshold public good games. The model draws on learning direction theory and impulse balance theory. We find good support for the model and demonstrate that it can explain the success rates observed in threshold public good experiments. The model is applied in a variety of dierent settings : we compare games with a full refund to those with no refund, consider changes in relative endowment, and consider changes in the step return and net reward.Public good, threshold, learning direction theory, impulse balance theory, counterfactual thinking

Effect of Larval Nutrition on Maternal mRNA Contribution to the Drosophila Egg.

Embryonic development begins under the control of maternal gene products, mRNAs and proteins that the mother deposits into the egg; the zygotic genome is activated some time later. Maternal control of early development is conserved across metazoans. Gene products contributed by mothers are critical to many early developmental processes, and set up trajectories for the rest of development. Maternal deposition of these factors is an often-overlooked aspect of parental investment. If the mother experiences challenging environmental conditions, such as poor nutrition, previous studies in Drosophila melanogaster have demonstrated a plastic response wherein these mothers may produce larger eggs to buffer the offspring against the same difficult environment. This additional investment can produce offspring that are more fit in the challenging environment. With this study, we ask whether D. melanogaster mothers who experience poor nutrition during their own development change their gene product contribution to the egg. We perform mRNA-Seq on eggs at a stage where all mRNAs are maternally derived, from mothers with different degrees of nutritional limitation. We find that nutritional limitation produces similar transcript changes at all degrees of limitation tested. Genes that have lower transcript abundance in nutritionally limited mothers are those involved in translation, which is likely one of the most energetically costly processes occurring in the early embryo. We find an increase in transcripts for transport and localization of macromolecules, and for the electron transport chain. The eggs produced by nutrition-limited mothers show a plastic response in mRNA deposition, which may better prepare the future embryo for development in a nutrition-limited environment

Deception in double extortion ransomware attacks:An analysis of profitability and credibility

Ransomware attacks have evolved with criminals using double extortion schemes, where they signal data exfiltration to inflate ransom demands. This development is further complicated by information asymmetry, where victims are compelled to respond to ambiguous and often deceptive signals from attackers. This study explores the complex interactions between criminals and victims during ransomware attacks, especially focusing on how data exfiltration is communicated. We use a signaling game to understand the strategies both parties use when dealing with uncertain information. We identify five distinct equilibria, each characterized by the criminals' varied approaches to signaling data exfiltration, influenced by the strategic parameters inherent in each attack scenario. Calibrating the game parameters with real-world like values, we identify the most probable equilibrium, offering insights into anticipated ransom amounts and corresponding payoffs for both victims and criminals. Our findings suggest criminals are likely to claim data exfiltration, true or not, highlighting a strategic advantage for intensifying attack efforts. The study underscores the need for victims' caution towards criminals' claims and highlights the unintended consequences of policies making false claims costlier for criminals.</p

Evaluation of perampanel as monotherapy for focal seizures: Experience from open-label extension studies

Perampanel, a selective, non-competitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist, is approved for adjunctive treatment of focal seizures, with or without secondarily generalized seizures, and for primary generalized tonic–clonic seizures in patients with epilepsy aged ≥ 12 years. Perampanel was recently approved for monotherapy use for focal seizures in the U.S.A. Anti-seizure drug monotherapy may be preferable to polytherapy, which is generally associated with increased toxicity, non-compliance, and cost. Here, we report cases where patients had converted to perampanel monotherapy during open-label extension (OLEx) portions of 9 Phase II and III studies. Of 2245 patients who enrolled in the OLEx studies, we identified 7 patients with drug-resistant focal seizures who discontinued all non-perampanel anti-seizure drugs and were maintained on perampanel monotherapy for ≥ 91 days until the end of data cut-off. Patients received perampanel monotherapy for up to 1099 days (157 weeks), most at a modal dose of 12 mg. Seizure data were available for 6 patients, of whom 5 had a ≥ 90% reduction in overall seizure frequency between baseline and their last 13-week period of monotherapy (3 were seizure-free). Perampanel monotherapy was generally well tolerated and the safety profile during perampanel monotherapy was consistent with clinical and post-marketing experience in the adjunctive setting. This analysis included a small proportion of patients with highly drug-resistant focal seizures who converted to monotherapy during OLEx studies. While these limited data are encouraging in suggesting that perampanel might be useful as a monotherapy, further studies are required to explore outcomes in a less drug-resistant population, where a larger proportion of patients might benefit from monotherapy. © 2017 The Author

Game Theoretic Modelling of a Ransom and Extortion Attack on Ethereum Validators

Consensus algorithms facilitate agreement on and resolution of blockchain functions, such as smart contracts and transactions. Ethereum uses a Proof-of-Stake (PoS) consensus mechanism, which depends on financial incentives to ensure that validators perform certain duties and do not act maliciously. Should a validator attempt to defraud the system, legitimate validators will identify this and then staked cryptocurrency is ‘burned’ through a process of slashing. In this paper, we show that an attacker who has compromised a set of validators could threaten to perform malicious actions that would result in slashing and thus, hold those validators to ransom. We use game theory to study how an attacker can coerce payment from a victim, for example by deploying a smart contract to provide a root of trust shared between attacker and victim during the extortion process. Our game theoretic model finds that it is in the interests of the validators to fully pay the ransom due to a lack of systemic protections for validators. Financial risk is solely placed on the victim during such an attack, with no mitigations available to them aside from capitulation (payment of ransom) in many scenarios. Such attacks could be disruptive to Ethereum and, likely, to many other PoS networks, if public trust in the validator system is eroded. We also discuss and evaluate potential mitigation measures arising from our analysis of the game theoretic model