Results 1  10
of
11
Quantum publickey cryptosystems
 in Proc. of CRYPT0 2000
, 2000
"... Abstract. This paper presents a new paradigm of cryptography, quantum publickey cryptosystems. In quantum publickey cryptosystems, all parties including senders, receivers and adversaries are modeled as quantum (probabilistic) polytime Turing (QPT) machines and only classical channels (i.e., no q ..."
Abstract

Cited by 37 (2 self)
 Add to MetaCart
(Show Context)
Abstract. This paper presents a new paradigm of cryptography, quantum publickey cryptosystems. In quantum publickey cryptosystems, all parties including senders, receivers and adversaries are modeled as quantum (probabilistic) polytime Turing (QPT) machines and only classical channels (i.e., no quantum channels) are employed. A quantum trapdoor oneway function, f, plays an essential role in our system, in which a QPT machine can compute f with high probability, any QPT machine can invert f with negligible probability, and a QPT machine with trapdoor data can invert f. This paper proposes a concrete scheme for quantum publickey cryptosystems: a quantum publickey encryption scheme or quantum trapdoor oneway function. The security of our schemes is based on the computational assumption (over QPT machines) that a class of subsetsum problems is intractable against any QPT machine. Our scheme is very efficient and practical if Shor’s discrete logarithm algorithm is efficiently realized on a quantum machine.
Cryptography in the boundedquantumstorage model
 QUANTUM PROTOCOLS IN A CLASSICAL ENVIRONMENT 367
, 2008
"... We initiate the study of twoparty cryptographic primitives with unconditional security, assuming that the adversary’s quantum memory is of bounded size. We show that oblivious transfer and bit commitment can be implemented in this model using protocols where honest parties need no quantum memory, ..."
Abstract

Cited by 8 (3 self)
 Add to MetaCart
(Show Context)
We initiate the study of twoparty cryptographic primitives with unconditional security, assuming that the adversary’s quantum memory is of bounded size. We show that oblivious transfer and bit commitment can be implemented in this model using protocols where honest parties need no quantum memory, whereas an adversarial player needs quantum memory of size at least n/2 in order to break the protocol, where n is the number of qubits transmitted. This is in sharp contrast to the classical boundedmemory model, where we can only tolerate adversaries with memory of size quadratic in honest players’ memory size. Our protocols are efficient and noninteractive and can be implemented using today’s technology. On the technical side, a new entropic uncertainty relation involving minentropy is established.
Unconditional security at a low cost
, 2006
"... By simulating four quantum key distribution (QKD) experiments and analyzing one decoystate QKD experiment, we compare two data postprocessing schemes based on security against individual attack by Lütkenhaus, and unconditional security analysis by GottesmanLoLütkenhausPreskill. Our results sho ..."
Abstract

Cited by 1 (1 self)
 Add to MetaCart
(Show Context)
By simulating four quantum key distribution (QKD) experiments and analyzing one decoystate QKD experiment, we compare two data postprocessing schemes based on security against individual attack by Lütkenhaus, and unconditional security analysis by GottesmanLoLütkenhausPreskill. Our results show that these two schemes yield close performances. Since the Holy Grail of QKD is its unconditional security, we conclude that one is better off considering unconditional security, rather than restricting to individual attacks.
Cryptography in the
, 2007
"... Cryptographic primitives such as oblivious transfer and bit commitment are impossible to realize if unconditional security is required against adversaries who are unbounded in running time and memory size. Therefore, it is a great challenge to come up with restrictions on the adversary’s capabilitie ..."
Abstract
 Add to MetaCart
Cryptographic primitives such as oblivious transfer and bit commitment are impossible to realize if unconditional security is required against adversaries who are unbounded in running time and memory size. Therefore, it is a great challenge to come up with restrictions on the adversary’s capabilities such that on one hand interesting cryptographic primitives become possible, but on the other hand the model is still realistic and as close to practice as possible. The boundedquantumstorage model is a prime example of such a cryptographic model. In this thesis, we initiate the study of cryptographic primitives with unconditional security under the sole assumption that the adversary’s quantum memory is of bounded size. Oblivious transfer and bit commitment can be implemented in this model using protocols where honest parties need no quantum memory, whereas an adversarial player needs to store at least a large fraction of the total number of transmitted qubits in order to break the protocol. This is in sharp contrast to
Completely secure practical cryptography
, 1999
"... Cryptography the art of secure communications, has been developed at least over 2500 years. Still at present, no perfectly secure as well as practically suitable classical or quantum cryptosystem exist. Statistically encoding the individual bit, here we present a practical key distribution techniqu ..."
Abstract
 Add to MetaCart
(Show Context)
Cryptography the art of secure communications, has been developed at least over 2500 years. Still at present, no perfectly secure as well as practically suitable classical or quantum cryptosystem exist. Statistically encoding the individual bit, here we present a practical key distribution technique which is absolutely secure both for classical and quantum keys. To achieve perfect security, noise has to be strategically introduced. Noise, a detrimental factor, which never becomes helpful anywhere in classical and quantum information theory, can be used as a gift of nature in our cryptosystem since fundamentally the coding of this cipher system does not follow the standard technique of classical and quantum information processing. 1 In cryptography, only Vernam cipher [1] provides perfect security [2] if the same key, initially shared between the legitimate users, is not used second time. As the same key can not be repeatedly used, it is an impractical cipher system for global use. Due to the nonexistence of practically suitable secure cipher system, data encryption standard (DES) [3] and public key distribution (PKD)
A Comprehensive Analysis
, 2000
"... The views, opinions and/or findings contained in this report are those of The MITRE Corporation and should not be construed as an official Government position, policy, or decision, unless designated by other documentation. Approved for public release; distribution unlimited. ..."
Abstract
 Add to MetaCart
(Show Context)
The views, opinions and/or findings contained in this report are those of The MITRE Corporation and should not be construed as an official Government position, policy, or decision, unless designated by other documentation. Approved for public release; distribution unlimited.
QuantumSpace Attacks
, 2008
"... Theoretical quantum key distribution (QKD) protocols commonly rely on the use of qubits (quantum bits). In reality, however, due to practical limitations, the legitimate users are forced to employ a larger quantum (Hilbert) space, say a quhexit (quantum sixdimensional) space, or even a much larger ..."
Abstract
 Add to MetaCart
(Show Context)
Theoretical quantum key distribution (QKD) protocols commonly rely on the use of qubits (quantum bits). In reality, however, due to practical limitations, the legitimate users are forced to employ a larger quantum (Hilbert) space, say a quhexit (quantum sixdimensional) space, or even a much larger quantum Hilbert space. Various specific attacks exploit of these limitations. Although security can still be proved in some very special cases, a general framework that considers such realistic QKD protocols, as well as attacks on such protocols, is still missing. We describe a general method of attacking realistic QKD protocols, which we call the ‘quantumspace attack’. The description is based on assessing the enlarged quantum space actually used by a protocol, the ‘quantum space of the protocol’. We demonstrate these new methods by classifying various (known) recent
A simple unbreakable code.
, 2000
"... A simple unbreakable cipher system is presented which uses the concept of ”pseudobits ” that has never been used in either classical or quantum cryptography. 1 Cryptography, the art of secure communication has been developed since the dawn of human civilization, but it has been mathematically treat ..."
Abstract
 Add to MetaCart
(Show Context)
A simple unbreakable cipher system is presented which uses the concept of ”pseudobits ” that has never been used in either classical or quantum cryptography. 1 Cryptography, the art of secure communication has been developed since the dawn of human civilization, but it has been mathematically treated by Shannon [1]. At present, we have different classical cryptosystems whose merits and demerits are discussed below. Vernam cipher [2]: It is proven secure [1] but it can not produce more absolutely secure bits than the shared secret bits. Due to this difficulty, it has not become popular, however it is still routinely used in diplomatic secure communication. Data encryption standard [3] and public key distribution system [4]: These are widely used cryptosystems because they can produce more computationally secure bits than the shared secret bits. The problem is that its
Perfectly secure cipher system.
, 2000
"... We present a perfectly secure cipher system based on the concept of fake bits which has never been used in either classical or quantum cryptography. 1 Cryptography, the art of secure communication has been developed since the dawn of human civilization, but it has been mathematically treated by Shan ..."
Abstract
 Add to MetaCart
(Show Context)
We present a perfectly secure cipher system based on the concept of fake bits which has never been used in either classical or quantum cryptography. 1 Cryptography, the art of secure communication has been developed since the dawn of human civilization, but it has been mathematically treated by Shannon [1]. At present, we have different classical cryptosystems whose merits and demerits are discussed below. Vernam cipher [2]: It is proven secure [1] but it can not produce more absolutely secure bits than the shared secret bits. Due to this difficulty, it has not become popular, however it is still routinely used in diplomatic secure communication. Data encryption standard [3] and public key distribution system [4]: These are widely used cryptosystems because they can produce more computationally secure bits than the shared secret bits. The problem is that its