A New Security Proof for Damgård’s ElGamal

2006 ◽  
pp. 150-158 ◽  
Author(s):  
Kristian Gjøsteen
Keyword(s):  
Security Proof

Digital Multi-Signature Scheme and Its Security Proof

2009 ◽  
Vol 31 (1) ◽  
pp. 176-183
Author(s):  
Xiao-Feng WANG ◽  
Jing ZHANG ◽  
Shang-Ping WANG
Keyword(s):  
Signature Scheme ◽  
Security Proof

scholarly journals Apply current exponential de Finetti theorem to realistic quantum key distribution

2014 ◽  
Vol 33 ◽  
pp. 1460370 ◽  
Author(s):  
Yi-Bo Zhao ◽  
Zhen-Qiang Yin
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Small Error ◽  
Heterodyne Detection ◽  
Finite Dimensional Subspace ◽  
Dimensional System ◽  
Finite Dimensional ◽  
Security Proof ◽  
De Finetti Theorem ◽  
De Finetti

In the realistic quantum key distribution (QKD), Alice and Bob respectively get a quantum state from an unknown channel, whose dimension may be unknown. However, while discussing the security, sometime we need to know exact dimension, since current exponential de Finetti theorem, crucial to the information-theoretical security proof, is deeply related with the dimension and can only be applied to finite dimensional case. Here we address this problem in detail. We show that if POVM elements corresponding to Alice and Bob's measured results can be well described in a finite dimensional subspace with sufficiently small error, then dimensions of Alice and Bob's states can be almost regarded as finite. Since the security is well defined by the smooth entropy, which is continuous with the density matrix, the small error of state actually means small change of security. Then the security of unknown-dimensional system can be solved. Finally we prove that for heterodyne detection continuous variable QKD and differential phase shift QKD, the collective attack is optimal under the infinite key size case.

File changes with security proof stored in cloud service systems

2017 ◽  
Vol 22 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Cheng-Yu Yang ◽  
Cheng-Ta Huang ◽  
Ya-Ping Wang ◽  
Yen-Wen Chen ◽  
Shiuh-Jeng Wang
Keyword(s):  
Cloud Service ◽  
Service Systems ◽  
Security Proof

scholarly journals On the security of $\alpha\eta$: response to 'some attacks on quantum-based cryptographic protocols'

2006 ◽  
Vol 6 (7) ◽  
pp. 561-582
Author(s):  
H.P. Yuen ◽  
R. Nair ◽  
E. Corndorf ◽  
G.S. Kanter ◽  
P. Kumar
Keyword(s):  
Coherent State ◽  
Optical Communications ◽  
A Priori ◽  
Key Generation ◽  
Generation System ◽  
New Approach ◽  
Security Proof ◽  
Grover Search ◽  
Channel Loss ◽  
Key Length

Lo and Ko have developed some attacks on the cryptosystem called $\alpha \eta$}, claiming that these attacks undermine the security of $\alpha\eta$ for both direct encryption and key generation. In this paper, we show that their arguments fail in many different ways. In particular, the first attack in [1] requires channel loss or length of known-plaintext that is exponential in the key length and is unrealistic even for moderate key lengths. The second attack is a Grover search attack based on `asymptotic orthogonality' and was not analyzed quantitatively in [1]. We explain why it is not logically possible to "pull back'' an argument valid only at $n=\infty$ into a limit statement, let alone one valid for a finite number of transmissions n. We illustrate this by a `proof' using a similar asymptotic orthogonality argument that coherent-state BB84 is insecure for any value of loss. Even if a limit statement is true, this attack is a priori irrelevant as it requires an indefinitely large amount of known-plaintext, resources and processing. We also explain why the attacks in [1] on $\alpha\eta$ as a key-generation system are based on misinterpretations of [2]. Some misunderstandings in [1] regarding certain issues in cryptography and optical communications are also pointed out. Short of providing a security proof for $\alpha\eta$, we provide a description of relevant results in standard cryptography and in the design of $\alpha\eta$ to put the above issues in the proper framework and to elucidate some security features of this new approach to quantum cryptography.

scholarly journals Permutation-Based Lightweight Authenticated Cipher with Beyond Conventional Security

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ping Zhang
Keyword(s):  
Hardware Implementation ◽  
Authenticated Encryption ◽  
Resource Constrained ◽  
Large Capacity ◽  
Efficiency Optimization ◽  
Security Proof ◽  
Almost All ◽  
Resource Constrained Devices ◽  
Constrained Devices

Lightweight authenticated ciphers are specially designed as authenticated encryption (AE) schemes for resource-constrained devices. Permutation-based lightweight authenticated ciphers have gained more attention in recent years. However, almost all of permutation-based lightweight AE schemes only ensure conventional security, i.e., about c / 2 -bit security, where c is the capacity of the permutation. This may be vulnerable for an insufficiently large capacity. This paper focuses on the stronger security guarantee and the better efficiency optimization of permutation-based lightweight AE schemes. On the basis of APE series (APE, APE R I , APE O W , and APE C A ), we propose a new improved permutation-based lightweight online AE mode APE + which supports beyond conventional security and concurrent absorption. Then, we derive a simple security proof and prove that APE + enjoys at most about min r , c -bit security, where r is the rate of the permutation. Finally, we discuss the properties of APE + on the hardware implementation.

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