Long distance two-party quantum cryptography made simple (2010)
Kerenidis, Iordanis, Wehner, Stephanie
Any two-party cryptographic primitive can be implemented using quantum communication under the assumption that it is difficult to store a large number of quantum states perfectly. However, achieving...
Implementation of two-party protocols in the noisy-storage model (2010)
Wehner, Stephanie, Curty, Marcos, Schaffner, Christian, Lo, Hoi-Kwong
The noisy-storage model allows the implementation of secure two-party protocols under the sole assumption that no large-scale reliable quantum storage is available to the cheating party. No quantum...
A transform of complementary aspects with applications to entropic uncertainty relations (2010)
Mandayam, Prabha, Balachandran, Niranjan, Wehner, Stephanie
Even though mutually unbiased bases and entropic uncertainty relations play an important role in quantum cryptographic protocols they remain ill understood. Here, we construct special sets of up to...
If quantum mechanics were more non-local it would violate the uncertainty principle (2010)
Oppenheim, Jonathan, Wehner, Stephanie
The two defining elements of quantum mechanics are Heisenberg's uncertainty principle, and a subtle form of non-locality which Einstein famously called "spooky action at a distance". The first...
Entropy in general physical theories (2010)
Short, Anthony J., Wehner, Stephanie
Information plays an important role in our understanding of the physical world. Hence we propose an entropic measure of information for any physical theory that admits systems, states and...
On the use of post-measurement information in state discrimination (2010)
Gopal, Deepthi, Wehner, Stephanie
We consider a special form of state discrimination in which after the measurement we are given additional information that may help us identify the state. This task plays a central role in the...
Entropic uncertainty relations — a survey (2010)
Wehner, Stephanie, Winter, Andreas
Uncertainty relations play a central role in quantum mechanics. Entropic uncertainty relations in particular have gained significant importance within quantum information, providing the foundation...
How to implement two-party protocols in the noisy-storage model (2009)
Wehner, Stephanie, Curty, Marcos, Schaffner, Christian, Lo, Hoi-Kwong
The noisy-storage model allows the implementation of secure two-party protocols under the sole assumption that no large-scale reliable quantum storage is available to the cheating party. No quantum...
Robust cryptography in the noisy-quantum-storage model (2009)
Schaffner, Christian, Terhal, Barbara, Wehner, Stephanie
It was shown in [42] that cryptographic primitives can be implemented based on the assumption that quantum storage of qubits is noisy. In this work we analyze a protocol for the universal task of...
Matthews, William, Wehner, Stephanie, Winter, Andreas
We consider the problem of ambiguous discrimination of two quantum states when we are only allowed to perform a restricted set of measurements. Let the bias of a POVM be defined as the total...
Robust cryptography in the noisy-quantum-storage model (2009)
Schaffner, Christian, Terhal, Barbara, Wehner, Stephanie
It was shown in [42] that cryptographic primitives can be implemented based on the assumption that quantum storage of qubits is noisy. In this work we analyze a protocol for the universal task of...
Entropy in general physical theories (2009)
Short, Anthony J., Wehner, Stephanie
Information plays an important role in our understanding of the physical world. We hence propose an entropic measure of information for any physical theory that admits systems, states and...
Relaxed uncertainty relations and information processing (2009)
Ver Steeg, Greg, Wehner, Stephanie
We consider a range of "theories'' that violate the uncertainty relation for anti-commuting observables derived. We first show that Tsirelson's bound for the CHSH inequality can be derived from this...
A Strong Converse for Classical Channel Coding Using Entangled Inputs (2009)
König, Robert, Wehner, Stephanie
A fully general strong converse for channel coding states that when the rate of sending classical information exceeds the capacity of a quantum channel, the probability of correctly decoding goes to...
Entropic uncertainty relations - A survey (2009)
Wehner, Stephanie, Winter, Andreas
Uncertainty relations play a central role in quantum mechanics. Entropic uncertainty relations in particular have gained significant importance within quantum information, providing the foundation...
Unconditional security from noisy quantum storage (2009)
Koenig, Robert, Wehner, Stephanie, Wullschleger, Juerg
We consider the implementation of two-party cryptographic primitives based on the sole assumption that no large-scale reliable quantum storage is available to the cheating party. We construct novel...
A strong converse for classical channel coding using entangled inputs (2009)
Koenig, Robert, Wehner, Stephanie
A fully general strong converse for channel coding states that when the rate of sending classical information exceeds the capacity of a quantum channel, the probability of correctly decoding goes to...
Lower bound on the dimension of a quantum system given measured data (2008)
Wehner, Stephanie, Christiandl, Matthias, Doherty, Andrew C.
We imagine an experiment on an unknown quantum mechanical system in which the system is prepared in various ways and a range of measurements are performed. For each measurement M and preparation rho...
Relaxed uncertainty relations and information processing (2008)
Steeg, Greg Ver, Wehner, Stephanie
We consider a range of "theories" that violate the uncertainty relation for anti-commuting observables derived in [JMP, 49, 062105 (2008)]. We first show that Tsirelson's bound for the CHSH...
Matthews, William, Wehner, Stephanie, Winter, Andreas
Every sufficiently rich set of measurements on a fixed quantum system defines a statistical norm on the states of that system via the optimal bias that can be achieved in distinguishing the states...
State Discrimination With Post-Measurement Information (2008)
Ballester, Manuael A., Wehner, Stephanie, Winter, Andreas
We introduce a new state discrimination problem in which we are given additional information about the state after the measurement, or more generally, after a quantum memory bound applies. The...
A lower bound on the dimension of a quantum system given measured data (2008)
Wehner, Stephanie, Christandl, Matthias, Doherty, Andrew C.
We imagine an experiment on an unknown quantum mechanical system in which the system is prepared in various ways and a range of measurements are performed. For each measurement M and preparation rho...
Possibility, impossibility, and cheat sensitivity of quantum-bit string commitment (2008)
Buhrman, Harry, Christandl, Matthias, Hayden, Patrick, Lo, Hoi-Kwong, Wehner, Stephanie
Robust Cryptography in the Noisy-Quantum-Storage Model (2008)
Schaffner, Christian, Terhal, Barbara, Wehner, Stephanie
It was shown in [WST08] that cryptographic primitives can be implemented based on the assumption that quantum storage of qubits is noisy. In this work we analyze a protocol for the universal task of...
Cryptography in a Quantum World (2008)
Quantum computing had a profound impact on cryptography. Shor's discovery of an efficient quantum algorithm for factoring large integers implies that many existing classical systems based on...
Cryptography in a Quantum World (2008)
Quantum computing had a profound impact on cryptography. Shor's discovery of an efficient quantum algorithm for factoring large integers implies that many existing classical systems based on...
Stephanie Wehner, Stephanie Wehner, Co-supervisor Dr, R. M. Wolf
The investigations were partially supported by the EU fifth framework project
The quantum moment problem and bounds on entangled multi-prover games (2008)
Doherty, Andrew C., Liang, Yeong-Cherng, Toner, Ben, Wehner, Stephanie
We study the quantum moment problem: Given a conditional probability distribution together with some polynomial constraints, does there exist a quantum state rho and a collection of measurement...
‘Computational Complexity of Quantum Hamiltonian Systems ’ in Leiden. (2008)
Supervisors Prof, Dr. Harry Buhrman, Committee Members, Prof Dr, Harry Buhrman, Christian Schaffner, ...
A survey of classical simulation methods
Lower bound on the dimension of a quantum system given measured data (2008)
Wehner, Stephanie, Christandl, Matthias, Doherty, Andrew C.
We imagine an experiment on an unknown quantum mechanical system in which the system is prepared in various ways and a range of measurements are performed. For each measurement M and preparation the...
Lower bound on the dimension of a quantum system given measured data (2008)
Wehner, Stephanie, Christandl, Matthias, Doherty, Andrew C.
We imagine an experiment on an unknown quantum mechanical system in which the system is prepared in various ways and a range of measurements are performed. For each measurement M and preparation the...
Lower bound on the dimension of a quantum system given measured data (2008)
Wehner, Stephanie, Christandl, Matthias, Doherty, Andrew C.
We imagine an experiment on an unknown quantum mechanical system in which the system is prepared in various ways and a range of measurements are performed. For each measurement M and preparation the...
Cryptography from Noisy Storage (2007)
Wehner, Stephanie, Schaffner, Christian, Terhal, Barbara
We show how to implement cryptographic primitives based on the realistic assumption that quantum storage of qubits is noisy. We thereby consider individual-storage attacks, i.e. the dishonest party...
Higher entropic uncertainty relations for anti-commuting observables (2007)
Wehner, Stephanie, Winter, Andreas
Uncertainty relations lie at the very core of quantum mechanics, and form the cornerstone of essentially all quantum cryptographic applications. In particular, they play an important role in...
Composable Security in the Bounded-Quantum-Storage Model (2007)
Wehner, Stephanie, Wullschleger, Jürg
We present a simplified framework for proving sequential composability in the quantum setting. In particular, we give a new, simulation-based, definition for security in the bounded-quantum-storage...
A simple family of nonadditive quantum codes (2007)
Smolin, John A., Smith, Graeme, Wehner, Stephanie
Most known quantum codes are additive, meaning the codespace can be described as the simultaneous eigenspace of an abelian subgroup of the Pauli group. While in some scenarios such codes are strictly...
Security of quantum bit string commitment depends on the information measure (2006)
Buhrman, Harry, Christandl, Matthias, Hayden, Patrick, Lo, Hoi-Kwong, Wehner, Stephanie
Unconditionally secure non-relativistic bit commitment is known to be impossible in both the classical and the quantum world. However, when committing to a string of n bits at once, how far can we...
State Discrimination with Post-Measurement Information (2006)
Ballester, Manuel A., Wehner, Stephanie, Winter, Andreas
We introduce a new state discrimination problem in which we are given additional information about the state after the measurement, or more generally, after a quantum memory bound applies. In...
Entropic uncertainty relations and locking: tight bounds for mutually unbiased bases (2006)
Ballester, Manuel A., Wehner, Stephanie
We prove tight entropic uncertainty relations for a large number of mutually unbiased measurements. In particular, we show that a bound derived from the result by Maassen and Uffink for 2 such...
Tsirelson bounds for generalized Clauser-Horne-Shimony-Holt inequalities (2005)
Quantum theory imposes a strict limit on the strength of non-local correlations. It only allows for a violation of the CHSH inequality up to the value 2 sqrt(2), known as Tsirelson's bound. In this...
Entanglement in Interactive Proof Systems with Binary Answers (2005)
If two classical provers share an entangled state, the resulting interactive proof system is significantly weakened [quant-ph/0404076]. We show that for the case where the verifier computes the XOR...
Implications of Superstrong Nonlocality for Cryptography (2005)
Buhrman, Harry, Christandl, Matthias, Unger, Falk, Wehner, Stephanie, Winter, Andreas
Non-local boxes are hypothetical ``machines'' that give rise to superstrong non-local correlations, leading to a stronger violation of Bell/CHSH inequalities than is possible within the framework of...
Analyzing Worms and Network Traffic using Compression (2005)
Internet worms have become a widespread threat to system and network operations. In order to fight them more efficiently, it is necessary to analyze newly discovered worms and attack patterns. This...
Possibility, Impossibility and Cheat-Sensitivity of Quantum Bit String Commitment (2005)
Buhrman, Harry, Christandl, Matthias, Hayden, Patrick, Lo, Hoi-Kwong, Wehner, Stephanie
Unconditionally secure non-relativistic bit commitment is known to be impossible in both the classical and the quantum worlds. But when committing to a string of n bits at once, how far can we...
Improved lower bounds for locally decodable codes and private information retrieval (2005)
Stephanie Wehner, Ronald De Wolf
We prove new lower bounds for locally decodable codes and private information retrieval. We show that a 2-query LDC encoding n-bit strings over an `-bit alphabet, where the decoder only uses b bits...
Improved lower bounds for locally decodable codes and private information retrieval (2005)
Stephanie Wehner, Ronald De Wolf
Abstract. We prove new lower bounds for locally decodable codes and private information retrieval. We show that a 2-query LDC encoding nbit strings over an ℓ-bit alphabet, where the decoder �...
Quantum Anonymous Transmissions (2004)
Christandl, Matthias, Wehner, Stephanie
We consider the problem of hiding sender and receiver of classical and quantum bits (qubits), even if all physical transmissions can be monitored. We present a quantum protocol for sending and...
Improved Lower Bounds for Locally Decodable Codes and Private Information Retrieval (2004)
Wehner, Stephanie, De Wolf, Ronald
We prove new lower bounds for locally decodable codes and private information retrieval. We show that a 2-query LDC encoding n-bit strings over an l-bit alphabet, where the decoder only uses b bits...
Quantum Computation and Privacy (2004)
Stephanie Wehner, Stephanie Wehner, Co-supervisor Dr, R. M. Wolf
Index 99 Preface "Les etoiles sont belles, a cause d'une fleur que l'on ne voit pas..." - Le Petit Prince, Antoine de Saint-Exupery. Quantum mechanics is one of the most...