Verifying sanitizer correctness through black-box learning: A symbolic finite transducer approach

String sanitizers are widely used functions for preventing injection attacks such as SQL injections and cross-site scripting (XSS). It is therefore crucial that the implementations of such string sanitizers are correct. We present a novel approach to reason about a sanitizer's correctness by automatically generating a model of the implementation...

Practical Mutation Testing for Smart Contracts

Solidity smart contracts operate in a hostile environment, which introduces the need for the adequate application of testing techniques to ensure mitigation of the risk of a security incident. Mutation testing is one such technique. It allows for the evaluation of the efficiency of a test suite in detecting faults in a program, allowing...

Multi-client predicate-only encryption for conjunctive equality tests

We propose the first multi-client predicate-only encryption scheme capable of efficiently testing the equality of two encrypted vectors. Our construction can be used for the privacy-preserving monitoring of relations among multiple clients. Since both the clients’ data and the predicates are encrypted, our system is suitable for situations in...

Will that smart contract really do what you expect it to do?

Smart contracts are believed to be the next step in inter-party automation; traditional trusted third parties are to be replaced by small pieces of code running on a distributed system that written by fallible humans. However, at the end of the day, these smart contracts controlling high-value assets are pieces of code written by fallible humans...

DECANTeR: DEteCtion of Anomalous outbouNd HTTP Traffic by Passive Application Fingerprinting

We present DECANTeR, a system to detect anomalous outbound HTTP communication, which passively extracts fingerprints for each application running on a monitored host. The goal of our system is to detect unknown malware and backdoor communication indicated by unknown fingerprints extracted from a host's network traffic. We evaluate a prototype...

Vote to link: Recovering from misbehaving anonymous users

Service providers are often reluctant to support anonymous access, because this makes it hard to deal with misbehaving users. Anonymous blacklisting and reputation systems can help prevent misbehaving users from causing more damage. However, by the time the user is blocked or has lost reputation, most of the damage has already been done. To help...

Reliably determining data leakage in the presence of strong attackers

We address the problem of determining what data has been leaked from a system after its recovery from a successful attack. This is a forensic process which is relevant to give a better understanding of the impact of a data breach, but more importantly it is becoming mandatory according to the recent developments of data breach notification laws....

Private sharing of IOCs and sightings

Information sharing helps to better protect computer sys- tems against digital threats and known attacks. However, since security information is usually considered sensitive, parties are hesitant to share all their information through public channels. Instead, they only exchange this informa- tion with parties with whom they already established...

Revocable privacy: Principles, use cases, and technologies

Security and privacy often seem to be at odds with one another. In this paper, we revisit the design principle of revocable privacy which guides the creation of systems that offer anonymity for people who do not violate a predefined rule, but can still have consequences for people who do violate the rule. We first improve the definition of...

Indicators of malicious SSL connections

Internet applications use SSL to provide data confidentiality to communicating entities. The use of encryption in SSL makes it impossible to distinguish between benign and malicious connections as the content cannot be inspected. Therefore, we propose and evaluate a set of indicators for malicious SSL connections, which is based on the...

Publicly Verifiable Private Aggregation of Time-Series Data

Aggregation of time-series data offers the possibility to learn certain statistics over data periodically uploaded by different sources. In case of privacy sensitive data, it is desired to hide every data provider's individual values from the other participants (including the data aggregator). Existing privacy preserving time-series data...

Designing Privacy-by-Design

The proposal for a new privacy regulation d.d. January 25th 2012 introduces sanctions of up to 2% of the annual turnover of enterprises. This elevates the importance of mitigation of privacy risks. This paper makes Privacy by Design more concrete, and positions it as the mechanism to mitigate these privacy risks. In this vision paper, we...

Privacy-preserving verification of clinical research

We treat the problem of privacy-preserving statistics verification in clinical research. We show that given aggregated results from statistical calculations, we can verify their correctness efficiently, without revealing any of the private inputs used for the calculation. Our construction is based on the primitive of Secure Multi-Party...

UbiKiMa: Ubiquitous authentication using a smartphone, migrating from passwords to strong cryptography

Passwords are the only ubiquitous form of authentication currently available on the web. Unfortunately, passwords are insecure. In this paper we therefore propose the use of strong cryptography, using the fact that users increasingly own a smartphone that can perform the required cryptographic operations on their behalf. This is not as trivial...

Revocable Privacy 2011 – use cases

In this document we have described and partially analysed a number of use cases where revocable privacy can help in providing more privacy for the user. We have seen that the use cases can be classified based primarily on the type of rule they encode. We classified threshold based, time based and predicate based rules. In addition we considered...