scholarly journals Qubit-based unclonable encryption with key recycling

2021 ◽  
Vol 21 (11-12) ◽  
pp. 901-930
Author(s):  
Daan Leermakers ◽  
Boris Skoric
Keyword(s):  
Communication Complexity ◽  
High Rate ◽  
Encryption Scheme ◽  
Message Length ◽  
Security Proof

We re-visit Unclonable Encryption as introduced by Gottesman in~2003 \cite{uncl}. We look at the combination of Unclonable Encryption and Key Recycling, while aiming for low communication complexity and high rate. We introduce a qubit-based prepare-and-measure Unclonable Encryption scheme with re-usable keys. Our scheme consists of a single transmission by Alice and a single classical feedback from Bob. The transmission from Alice to Bob consists entirely of qubits. The rate, defined as the message length divided by the number of qubits, is higher than what can be achieved using Gottesman's scheme~\cite{uncl}. We provide a security proof based on the diamond norm distance, taking noise into account.

scholarly journals Sender-equivocable encryption schemes secure against chosen-ciphertext attacks revisited

2015 ◽  
Vol 25 (2) ◽  
pp. 415-430
Author(s):  
Zhengan Huang ◽  
Shengli Liu ◽  
Baodong Qin ◽  
Kefei Chen
Keyword(s):  
Security Analysis ◽  
Encryption Scheme ◽  
Authentication Code ◽  
Security Proof ◽  
Encryption Schemes ◽  
Challenge Ciphertext ◽  
The Cross ◽  
Security Game

Abstract Fehr et al. (2010) proposed the first sender-equivocable encryption scheme secure against chosen-ciphertext attacks (NCCCA) and proved that NC-CCA security implies security against selective opening chosen-ciphertext attacks (SO-CCA). The NC-CCA security proof of the scheme relies on security against substitution attacks of a new primitive, the “crossauthentication code”. However, the security of the cross-authentication code cannot be guaranteed when all the keys used in the code are exposed. Our key observation is that, in the NC-CCA security game, the randomness used in the generation of the challenge ciphertext is exposed to the adversary. Based on this observation, we provide a security analysis of Fehr et al.’s scheme, showing that its NC-CCA security proof is flawed. We also point out that the scheme of Fehr et al. encrypting a single-bit plaintext can be refined to achieve NC-CCA security, free of the cross-authentication code. Furthermore, we propose the notion of “strong cross-authentication code”, apply it to Fehr et al.’s scheme, and show that the new version of the latter achieves NC-CCA security for multi-bit plaintexts.

scholarly journals Hierarchical authority based weighted attribute encryption scheme

2019 ◽  
Vol 16 (3) ◽  
pp. 797-813
Author(s):  
Qiuting Tian ◽  
Dezhi Han ◽  
Yanmei Jiang
Keyword(s):  
Data Storage ◽  
Cloud Storage ◽  
Encryption Scheme ◽  
Storage Security ◽  
Fine Grained ◽  
Security Proof ◽  
Attribute Based Encryption ◽  
Encryption Schemes ◽  
And Performance ◽  
Cloud Storage Environment

With the development of cloud storage technology, data storage security has become increasingly serious. Aiming at the problem that existing attribute-based encryption schemes do not consider hierarchical authorities and the weight of attribute. A hierarchical authority based weighted attribute encryption scheme is proposed. This scheme will introduce hierarchical authorities and the weight of attribute into the encryption scheme, so that the authorities have a hierarchical relationship and different attributes have different importance. At the same time, the introduction of the concept of weight makes this scheme more flexible in the cloud storage environment and enables fine-grained access control. In addition, this scheme implements an online/offline encryption mechanism to improve the security of stored data. Security proof and performance analysis show that the scheme is safe and effective, and it can resist collusion attacks by many malicious users and authorization centers. It is more suitable for cloud storage environments than other schemes.

scholarly journals Security proof for quantum key recycling with noise

2019 ◽  
Vol 19 (11&12) ◽  
pp. 913-934
Author(s):  
Daan Leermakers ◽  
Boris Skoric
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
High Rate ◽  
High Dimensional ◽  
Not Given ◽  
Trace Distance ◽  
Security Proof ◽  
Quantum Authentication ◽  
Authentication Schemes ◽  
State Encoding

Quantum Key Recycling aims to re-use the keys employed in quantum encryption and quantum authentication schemes. QKR protocols can achieve better round complexity than Quantum Key Distribution. We consider a QKR protocol that works with qubits, as opposed to high-dimensional qudits. A security proof was given by Fehr and Salvail in the case where there is practically no noise. A high-rate scheme for the noisy case was proposed by \v{S}kori\'{c} and de Vries, based on eight-state encoding. However, a security proof was not given. In this paper we introduce a protocol modification and provide a security proof. The modified protocol has high rate not only for 8-state encoding, but also 6-state and BB84 encoding. Our proof is based on a bound on the trace distance between the real quantum state of the system and a state in which the keys are completely secure. It turns out that the rate is higher than suggested by previous results. Asymptotically the rate equals the rate of Quantum Key Distribution with one-way postprocessing.

scholarly journals A Modified Symmetric Key Fully Homomorphic Encryption Scheme Based on Read-Muller Code

2021 ◽  
Vol 18 (2(Suppl.)) ◽  
pp. 0899
Author(s):  
RatnaKumari Challa ◽  
VijayaKumari Gunta
Keyword(s):  
Coding Theory ◽  
Homomorphic Encryption ◽  
Security Analysis ◽  
Encryption Scheme ◽  
Fully Homomorphic Encryption ◽  
Chosen Plaintext Attack ◽  
Security Proof ◽  
Expansion Technique ◽  
Cryptographic Primitive ◽  
Symmetric Key

Homomorphic encryption became popular and powerful cryptographic primitive for various cloud computing applications. In the recent decades several developments has been made. Few schemes based on coding theory have been proposed but none of them support unlimited operations with security.   We propose a modified Reed-Muller Code based symmetric key fully homomorphic encryption to improve its security by using message expansion technique. Message expansion with prepended random fixed length string provides one-to-many mapping between message and codeword, thus one-to many mapping between plaintext and ciphertext. The proposed scheme supports both (MOD 2) additive and multiplication operations unlimitedly.   We make an effort to prove the security of the scheme under indistinguishability under chosen-plaintext attack (IND-CPA) through a game-based security proof. The security proof gives a mathematical analysis and its complexity of hardness. Also, it presents security analysis against all the known attacks with respect to the message expansion and homomorphic operations.

Fully Secure Ciphertext-Policy Attribute-Based Encryption in Prime Order Group

2012 ◽  
Vol 263-266 ◽  
pp. 2920-2923
Author(s):  
Song Feng Lu ◽  
Yu Zhang ◽  
Jie Sun ◽  
Liping Yang
Keyword(s):  
Prime Order ◽  
Encryption Scheme ◽  
Secret Key ◽  
Order Group ◽  
Security Proof ◽  
Attribute Based Encryption ◽  
Ciphertext Policy

We present a fully secure ciphertext-policy attribute-based encryption (CP-ABE) scheme in prime order group by using a tool which can convert composite order paring-based encryption scheme into prime order one. Although, a fully secure CP-ABE scheme in prime order group has been proposed recently, our scheme needs less master secret key size and can be seen as a different version of it. Besides, the sketch of our scheme's security proof is also given.

scholarly journals Quantum digital signatures with smaller public keys

2021 ◽  
Vol 21 (11-12) ◽  
pp. 955-973
Author(s):  
Boris Skoric
Keyword(s):  
Digital Signatures ◽  
Numerical Results ◽  
Public Key ◽  
The Public ◽  
Private Key ◽  
Message Length ◽  
Security Proof ◽  
Public Keys

We introduce a variant of quantum signatures in which nonbinary symbols are signed instead of bits. The public keys are fingerprinting states, just as in the scheme of Gottesman and Chuang \cite{GC2001}, but we allow for multiple ways to reveal the private key partially. The effect of this modification is a reduction of the number of qubits expended per message bit. Asymptotically the expenditure becomes as low as one qubit per message bit. We give a security proof, and we present numerical results that show how the improvement in public key size depends on the message length.

scholarly journals Designated server-aided revocable identity-based keyword search on lattice

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Ying Guo ◽  
Fei Meng ◽  
Leixiao Cheng ◽  
Xiaolei Dong ◽  
Zhenfu Cao
Keyword(s):  
Standard Model ◽  
Keyword Search ◽  
Key Generation ◽  
Encryption Scheme ◽  
Security Proof ◽  
The Standard Model ◽  
Secret Keys ◽  
Identity Based ◽  
Designated Server ◽  
Learning With Errors Problem

AbstractPublic key encryption scheme with keyword search is a promising technique supporting search on encrypted data without leaking any information about the keyword. In real applications, it’s critical to find an effective revocation method to revoke users in multi-user cryptosystems, when user’s secret keys are exposed. In this paper, we propose the first designated server-aided revocable identity-based encryption scheme with keyword search (dSR-IBKS) from lattice. The dSR-IBKS model requires each user to keep just one private key corresponding with his identity and does not need to communicate with the key generation center or the server during key updating. We have proved that our scheme can achieve chosen keyword indistinguishability in the standard model. In particular, our scheme can designate a unique tester to test and return the search results, therefore no other entity can guess the keyword embedded in the ciphertext by generating search queries and doing the test by itself. We provide a formal security proof of our scheme assuming the hardness of the learning with errors problem on the standard model.

scholarly journals Designated Server-Aided Revocable Identity-based Keyword Search on Lattice

2021 ◽  
Author(s):  
Ying Guo ◽  
Fei Meng ◽  
Leixiao Cheng ◽  
Xiaolei Dong ◽  
Zhenfu Cao
Keyword(s):  
Standard Model ◽  
Keyword Search ◽  
Key Generation ◽  
Encryption Scheme ◽  
Security Proof ◽  
The Standard Model ◽  
Secret Keys ◽  
Identity Based ◽  
Learning With Errors ◽  
Designated Server

Abstract Public key encryption scheme with keyword search (PEKS) is a promising technique supporting search on encrypted data without leaking any information about the keyword. In real applications, it's critical to find an effective revocation method to revoke users in multi-user cryptosystems, when user's secret keys are exposed.In this paper, we propose the first designated server-aided revocable identity-based encryption scheme with keyword search (dSR-IBKS) from lattice. The dSR-IBKS model requires each user to keep just one private key corresponding with his identity and does not need to communicate with the key generation center or the server during key updating. We have proved that our scheme can achieve chosen keyword indistinguishability in the standard model. In particular, our scheme can designate a unique tester to test and return the search results, therefore no other entity can guess the keyword embedded in the ciphertext by generating search queries and doing the test by itself. We provide a formal security proof of our scheme assuming the hardness of the learning with errors (LWE) problem on the standard model.

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