An exploratory study about contamination of pens of finishing pigs by ubiquitous Salmonella

Salmonella is one of the most common food-borne pathogens transmitted to humans and human salmonellosis is primarily caused by contaminated food. Porcine products have been identified as important food vehicles in outbreaks of salmonellosis (I, 2, 3). In France, the majority of Salmonella infected pig herds are sub-clinically infected. S. Choleraesuis does not occur and only ubiquitous serotypes are isolated (4). Sub-clinically infection is characterized by intermittent shedding of small numbers of Salmonella. In these sub-clinically infected pig herds, an infectioncontamination-infection cycle is maintained with mainly an endemic house flora of Salmonella enterica (5). When contaminated batches from these farms are processed on the slaughter line, slaughtering practices contribute to Salmonella dissemination and carcass contamination. Within batches, there is a strong correlation between the proportion of animals with Salmonella spp. in their feces and the proportion of contaminated carcasses at the end of the line (6, 7). As a result of subclinical Salmonella infection in pig herds, Salmonella contamination of pork carcasses constitutes a threat to human health. The influence of a wide range of factors on subclinical Salmonella contamination of pig farms is not well known. A good understanding of risk factors for Salmonella contamination of pig herds is an essential stake in order to avoid Salmonella spread within herds and between herds and slaughterhouses. Thus, the aim of this study was to investigate potential risk factors for the presence of ubiquitous Salmonella in the finishing sheds of farrow-to-finish farms in France

abstractXOR: A global constraint dedicated to differential cryptanalysis

International audienceConstraint Programming models have been recently proposed to solve cryptanalysis problems for symmetric block ciphers such as AES. These models are more efficient than dedicated approaches but their design is difficult: straightforward models do not scale well and it is necessary to add advanced constraints derived from cryptographic properties. We introduce a global constraint which simplifies the modelling step and improves efficiency. We study its complexity, introduce propagators and experimentally evaluate them on two cryptanalysis problems (single-key and related-key) for two block ciphers (AES and Midori)

MILP-based Differential Attack on Round-reduced GIFT

At Asiacrypt 2014, Sun et al. proposed a MILP model to search for differential characteristics of bit-oriented block ciphers. In this paper, we improve this model to search for differential characteristics of GIFT, a new lightweight block cipher proposed at CHES 2017. GIFT has two versions, namely GIFT-64 and GIFT-128. For GIFT-64, we find the best 12-round differential characteristic and a number of iterative 4-round differential characteristics with our MILP-based model. We give a key-recovery attack on 19-round GIFT-64. For GIFT-128, we find a 18-round differential characteristic and give the first attack on 22-round GIFT-128

Breaking and Fixing the HB+DB protocol

HB+ is a lightweight authentication scheme, which is secure against passive attacks if the Learning Parity with Noise Prob- lem (LPN) is hard. However, HB+ is vulnerable to a key- recovery, man-in-the-middle (MiM) attack dubbed GRS. The HB+DB protocol added a distance-bounding dimension to HB+, and was experimentally proven to resist the GRS attack. We exhibit several security flaws in HB+DB. First, we refine the GRS strategy to induce a different key-recovery MiM attack, not deterred by HB+DB's distance bounding. Second, we prove HB+DB impractical as a secure distance-bounding (DB) protocol, as its DB security-levels scale poorly compared to other DB protocols. Third, we refute that HB+DB's security against passive attackers relies on the hardness of LPN; more-over, (erroneously) requiring such hardness lowers HB+DB's efficiency and security. We also propose a new distance-bounding protocol called BLOG. It retains parts of HB+DB, yet BLOG is provably secure and enjoys better (asymptotical) security

An exploratory study about contamination of pens of finishing pigs by ubiquitous Salmonella

Salmonella is one of the most common food-borne pathogens transmitted to humans and human salmonellosis is primarily caused by contaminated food. Porcine products have been identified as important food vehicles in outbreaks of salmonellosis (I, 2, 3). In France, the majority of Salmonella infected pig herds are sub-clinically infected. S. Choleraesuis does not occur and only ubiquitous serotypes are isolated (4). Sub-clinically infection is characterized by intermittent shedding of small numbers of Salmonella. In these sub-clinically infected pig herds, an infectioncontamination-infection cycle is maintained with mainly an endemic "house flora" of Salmonella enterica (5). When contaminated batches from these farms are processed on the slaughter line, slaughtering practices contribute to Salmonella dissemination and carcass contamination. Within batches, there is a strong correlation between the proportion of animals with Salmonella spp. in their feces and the proportion of contaminated carcasses at the end of the line (6, 7). As a result of subclinical Salmonella infection in pig herds, Salmonella contamination of pork carcasses constitutes a threat to human health. The influence of a wide range of factors on subclinical Salmonella contamination of pig farms is not well known. A good understanding of risk factors for Salmonella contamination of pig herds is an essential stake in order to avoid Salmonella spread within herds and between herds and slaughterhouses. Thus, the aim of this study was to investigate potential risk factors for the presence of ubiquitous Salmonella in the finishing sheds of farrow-to-finish farms in France.</p