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18 January 2019
TU Darmstadt
Current topics of interest include (but are not limited to):
- Blockchains and cryptocurrencies
- Secure cryptographic implementations
- Leakage/tamper resilient cryptography
- Distributed cryptography
The application must include a curriculum vitae, a short research statement, and names of 2 contacts that can provide reference about the applicant and her/his work. The candidate shall be able to show solid expertise in cryptography/IT Security illustrated in form of publications at major crypto/security venues such as CRYPTO, EUROCRYPT, ASIACRYPT, TCC, PKC, CHES, FC, ACM CCS, IEEE S&P, USENIX Security, NDSS etc.
The position can be partially funded by the Ethereum Foundation and hence offers an internationally competitive salary including social benefits, and the opportunity for close collaboration with one of the leading cryptocurrencies.
TU Darmstadt offers excellent working environment in the heart of the Rhein-Main area, and has a strong institute for research on IT security with more than 300 researchers working on all aspects of cybersecurity.
Review of applications starts immediately until the position is filled.
Contact: Prof. Sebastian Faust, Contact: sebastian.faust(at)cs(dot)tu-darmstadt(dot)de
Closing date for applications: 20 March 2019
TU Wien, Security & Privacy group
• security and privacy
• cryptography
• distributed systems
Outstanding candidates in other disciplines are also encouraged to apply. The successful candidates will conduct research in the area of blockchain and distributed ledger technologies. Research topics may cover (but are not limited to):
• formal cryptographic models for security and privacy in blockchain
• cryptographic protocols for blockchain applications
• implementation and evaluation of off-chain protocols in the COMIT network
The employment is a full-time position (40 hrs/week) and the salary is internationally competitive. The working language will be English, knowledge of German is not required.
Interested candidates should send
• a motivation letter
• a transcript of records
• a curriculum vitae
• a publication list
• contact information for two referees
to pedro.sanchez (at) tuwien.ac.at.
TU Wien offers an outstanding research environment and numerous professional development opportunities. The Faculty of Informatics is the largest one in Austria and is consistently ranked among the best in Europe. Vienna features a vibrant and excellence-driven research landscape, with a special focus on blockchain technologies. Finally, Vienna has been consistently ranked by Mercer over the last years the best city for quality of life worldwide.
CoBloX is a research and development (R&D) lab with a goal to make cryptocurrencies instantly spendable anytime anywhere. The mission of CoBloX is to connect anyone and anything to decentralized services in order to build the very fabric of the decentralized future. CoBloX is the creator of the COMIT network which is a completely open source and free to use the network. It is powered by unique cryptographic protocols which allow seamless and trustless cross-blockchain transactions.
Closing date for applications: 31 March 2019
Contact: Pedro Moreno-Sanchez
More information: https://secpriv.tuwien.ac.at/thesis_and_job_opportunities
Qian Guo, Thomas Johansson, Alexander Nilsson
17 January 2019
Lisa Kohl
Bartosz Zoltak
Vadim Lyubashevsky, Gregor Seiler
Stephan Krenn, Henrich C. Pöhls, Kai Samelin, Daniel Slamanig
We extend PSs to be fully invisible. This strengthened notion guarantees that an outsider can neither decide which parts of a message can be edited nor which parts can be redacted. To achieve our goal, we introduce the new notions of Invisible RSSs and Invisible Non-Accountable SSSs (SSS'), along with a consolidated framework for aggregate signatures. Using those building blocks, our resulting construction is significantly more efficient than the original scheme by Krenn et al., which we demonstrate in a prototypical implementation.
Aijun Ge, Puwen Wei
Aron Gohr
While our attack is based on a known input difference taken from the literature, we also show that neural networks can be used to rapidly (within a matter of minutes on our machine) find good input differences without using prior human cryptanalysis.
Shuichi Katsumata, Shota Yamada
To remedy our rather poor understanding regarding NIPE schemes without bilinear maps, we provide two methods for constructing NIPE schemes: a direct construction from lattices and a generic construction from functional encryption schemes for inner products (LinFE). For our first direct construction, it highly departs from the traditional lattice-based constructions and we rely heavily on new tools concerning Gaussian measures over multi-dimensional lattices to prove security. For our second generic construction, using the recent constructions of LinFE schemes as building blocks, we obtain the first NIPE constructions based on the DDH and DCR assumptions. In particular, we obtain the first NIPE schemes without bilinear maps or lattices.
Daniele Cozzo, Nigel P. Smart
Myrto Arapinis, Andriana Gkaniatsou, Dimitris Karakostas, Aggelos Kiayias
Zhedong Wang, Xiong Fan, Feng-Hao Liu
Steven Galbraith, Jake Massimo, Kenneth G. Paterson
For finite fields, we show how to construct DH parameters $(p,q,g)$ for the safe prime setting in which $p=2q+1$ is prime, $q$ is relatively smooth but fools random-base Miller-Rabin primality testing with some reasonable probability, and $g$ is of order $q$ mod $p$. The construction involves modifying and combining known methods for obtaining Carmichael numbers. Concretely, we provide an example with 1024-bit $p$ which passes OpenSSL's Diffie-Hellman validation procedure with probability $2^{-24}$ (for versions of OpenSSL prior to 1.1.0i). Here, the largest factor of $q$ has 121 bits, meaning that the DLP can be solved with about $2^{64}$ effort using the Pohlig-Hellman algorithm. We go on to explain how this parameter set can be used to mount offline dictionary attacks against PAKE protocols.
In the elliptic curve case, we use an algorithm of Broker and Stevenhagen to construct an elliptic curve $E$ over a finite field ${\mathbb{F}}_p$ having a specified number of points $n$. We are able to select $n$ of the form $h\cdot q$ such that $h$ is a small co-factor, $q$ is relatively smooth but fools random-base Miller-Rabin primality testing with some reasonable probability, and $E$ has a point of order $q$. Concretely, we provide example curves at the 128-bit security level with $h=1$, where $q$ passes a single random-base Miller-Rabin primality test with probability $1/4$ and where the elliptic curve DLP can be solved with about $2^{44}$ effort. Alternatively, we can pass the test with probability $1/8$ and solve the elliptic curve DLP with about $2^{35.5}$ effort. These ECDH parameter sets lead to similar attacks on PAKE protocols relying on elliptic curves.
Our work shows the importance of performing proper (EC)DH parameter validation in cryptographic implementations and/or the wisdom of relying on standardised parameter sets of known provenance.