Colliding X.509 Certificates

We announce the construction of a pair of valid X.509 certificates with identical signatures

An Evaluated Certification Services System for the German National Root CA - Legally Binding and Trustworthy Transactions in E-Business and E-Government

National Root CAs enable legally binding E-Business and E-Government transactions. This is a report about the development, the evaluation and the certification of the new certification services system for the German National Root CA. We illustrate why a new certification services system was necessary, and which requirements to the new system existed. Then we derive the tasks to be done from the mentioned requirements. After that we introduce the initial situation at the beginning of the project. We report about the very process and talk about some unfamiliar situations, special approaches and remarkable experiences. Finally we present the ready IT system and its impact to E-Business and E-Government.Comment: 6 pages; 1 figure; IEEE style; final versio

Chosen-Prefix Collisions for MD5 and Applications

We present a novel, automated way to find differential paths for MD5. Its main application is in the construction of \emph{chosen-prefix collisions}. We have shown how, at an approximate expected cost of $2^{39}$ calls to the MD5 compression function, for any two chosen message prefixes $P$ and $P'$, suffixes $S$ and $S'$ can be constructed such that the concatenated values $P\|S$ and $P'\|S'$ collide under MD5. The practical attack potential of this construction of chosen-prefix collisions is of greater concern than the MD5-collisions that were published before. This is illustrated by a pair of MD5-based X.509 certificates one of which was signed by a commercial Certification Authority (CA) as a legitimate website certificate, while the other one is a certificate for a rogue CA that is entirely under our control (cf.\ \url{http://www.win.tue.nl/hashclash/rogue-ca/}). Other examples, such as MD5-colliding executables, are presented as well. More details can be found on \url{http://www.win.tue.nl/hashclash/ChosenPrefixCollisions/}

Security Issues of the Digital Certificates within Public Key Infrastructures

The paper presents the basic byte level interpretation of an X.509 v3 digital certificate according to ASN.1 DER/BER encoding. The reasons for byte level analysis are various and important. For instance, a research paper has mentioned how a PKI security may be violated by MD5 collision over information from the certificates. In order to develop further studies on the topic a serious knowledge about certificate structure is necessary.digital certificates, certificates authority, ASN.1 DER/BER, PKI

SciTokens: Capability-Based Secure Access to Remote Scientific Data

The management of security credentials (e.g., passwords, secret keys) for computational science workflows is a burden for scientists and information security officers. Problems with credentials (e.g., expiration, privilege mismatch) cause workflows to fail to fetch needed input data or store valuable scientific results, distracting scientists from their research by requiring them to diagnose the problems, re-run their computations, and wait longer for their results. In this paper, we introduce SciTokens, open source software to help scientists manage their security credentials more reliably and securely. We describe the SciTokens system architecture, design, and implementation addressing use cases from the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration and the Large Synoptic Survey Telescope (LSST) projects. We also present our integration with widely-used software that supports distributed scientific computing, including HTCondor, CVMFS, and XrootD. SciTokens uses IETF-standard OAuth tokens for capability-based secure access to remote scientific data. The access tokens convey the specific authorizations needed by the workflows, rather than general-purpose authentication impersonation credentials, to address the risks of scientific workflows running on distributed infrastructure including NSF resources (e.g., LIGO Data Grid, Open Science Grid, XSEDE) and public clouds (e.g., Amazon Web Services, Google Cloud, Microsoft Azure). By improving the interoperability and security of scientific workflows, SciTokens 1) enables use of distributed computing for scientific domains that require greater data protection and 2) enables use of more widely distributed computing resources by reducing the risk of credential abuse on remote systems.Comment: 8 pages, 6 figures, PEARC '18: Practice and Experience in Advanced Research Computing, July 22--26, 2018, Pittsburgh, PA, US

Chosen-prefix collisions for MD5 and applications

We present a novel, automated way to find differential paths for MD5. Its main application is in the construction of chosen-prefix collisions. We have shown how, at an approximate expected cost of 239 calls to the MD5 compression function, for any two chosen message prefixes P and P', suffixes S and S' can be constructed such that the concatenated values P||S and P'||S' collide under MD5. The practical attack potential of this construction of chosen-prefix collisions is of greater concern than the MD5-collisions that were published before. This is illustrated by a pair of MD5-based X.509 certificates one of which was signed by a commercial Certification Authority (CA) as a legitimate website certificate, while the other one is a certificate for a rogue CA that is entirely under our control (cf. http://www.win.tue.nl/hashclash/rogue-ca/). Other examples, such as MD5-colliding executables, are presented as well. More details can be found on http://www.win.tue.nl/hashclash/ChosenPrefixCollisions/

Safety Barrier Certificates for Heterogeneous Multi-Robot Systems

This paper presents a formal framework for collision avoidance in multi-robot systems, wherein an existing controller is modified in a minimally invasive fashion to ensure safety. We build this framework through the use of control barrier functions (CBFs) which guarantee forward invariance of a safe set; these yield safety barrier certificates in the context of heterogeneous robot dynamics subject to acceleration bounds. Moreover, safety barrier certificates are extended to a distributed control framework, wherein neighboring agent dynamics are unknown, through local parameter identification. The end result is an optimization-based controller that formally guarantees collision free behavior in heterogeneous multi-agent systems by minimally modifying the desired controller via safety barrier constraints. This formal result is verified in simulation on a multi-robot system consisting of both cumbersome and agile robots, is demonstrated experimentally on a system with a Magellan Pro robot and three Khepera III robots.Comment: 8 pages version of 2016ACC conference paper, experimental results adde