Lengths May Break Privacy – Or How to Check for Equivalences with Length

Security protocols have been successfully analyzed using symbolic models, where messages are represented by terms and protocols by processes. Privacy properties like anonymity or untraceability are typically expressed as equivalence between processes. While some decision procedures have been proposed for automatically deciding process equivalence, all existing approaches abstract away the information an attacker may get when observing the length of messages. In this paper, we study process equivalence with length tests. We first show that, in the static case, almost all existing decidability results (for static equivalence) can be extended to cope with length tests. In the active case, we prove decidability of trace equivalence with length tests, for a bounded number of sessions and for standard primitives. Our result relies on a previous decidability result from Cheval et al (without length tests). Our procedure has been implemented and we have discovered a new flaw against privacy in the biometric passport protocol

P-136: Do sudden death & fatal myocardial infarction have the same risk factors in primary prevention?

Objectifs : Sudden death, defined as a death which happens within 1 hour from the first symptom, is classified commonly as a coronary accident. Myocardial infarction is proposed as principal cause of sudden death. The frequency of sudden death is higher than that of fatal myocardial infarction. A recent overview showed that blood pressure lowering drugs did not decrease sudden death risk, whereas they decrease the risk of fatal myocardial infarction. We analyzed here the risk factors of sudden death and fatal myocardial infarction to provide more insight of the relation between these two accidents. Méthodes : We used Cox model to build the risk scores for two studied accidents on R (version 3.2.2), based on 15279 individual data in placebo group from seven randomized controlled trials (six of INDANA database in hypertension & one in type 2 diabetes Diahhycab)

CO-05: The first risk score for sudden death prediction in primary prevention patients.

BACKGROUND: Sudden death defined as a death within 1h from the onset of symptom, is a common cardiovascular accident, even more frequent than fatal myocardial infarction. Up to now, DUKE is the only sudden death risk predictor and it was designed specifically for patients of high coronary risk. We constructed here the first sudden death risk score for primary prevention, developed in patients with hypertension and type 2 diabetes. METHODS: We used the Cox model to build this risk score on R (version 3.2.2) based on 30 560 individual data from seven randomized controlled trials (six of INDANA database in hypertension & one in type 2 diabetes Diahhycab). RESULTS: There was no treatment effect and no interaction between treatment and other covariates on the risk of sudden death. This allowed us to develop the model on both treatment/placebo groups. We identified seven risk factors of sudden death : age, sex (male), smoking, cholesterolemia, systolic blood pressure, baseline of type 2 diabetes and history of myocardial infarction. The discrimination performance of the tool was fair (area under the receiver operating characteristic curve (AUC) was about 70%). CONCLUSIONS: Our work provides the first risk score for sudden death prediction in primary prevention patients. This risk score, in particular in hypertension and type 2 diabetes could help stratify patients in order to optimize preventive therapeutic strategies in primary prevention. Further research on sudden death is required to better prevent this highly frequent form of death