scholarly journals Efficient Signatures with Tight Real World Security in the Random-Oracle Model

2014 ◽  
pp. 370-383 ◽  
Author(s):  
Christoph Bader
Keyword(s):  
Real World ◽  
Random Oracle Model ◽  
Random Oracle

scholarly journals On the Tight Security of TLS 1.3: Theoretically Sound Cryptographic Parameters for Real-World Deployments

2021 ◽  
Vol 34 (3) ◽  
Author(s):  
Denis Diemert ◽  
Tibor Jager
Keyword(s):  
Real World ◽  
Large Scale ◽  
Random Oracle Model ◽  
Building Blocks ◽  
Random Oracle ◽  
Security Proof ◽  
Security Guarantees ◽  
Digital Signature Scheme ◽  
Tight Security ◽  
Selection Of

AbstractWe consider the theoretically sound selection of cryptographic parameters, such as the size of algebraic groups or RSA keys, for TLS 1.3 in practice. While prior works gave security proofs for TLS 1.3, their security loss is quadratic in the total number of sessions across all users, which due to the pervasive use of TLS is huge. Therefore, in order to deploy TLS 1.3 in a theoretically sound way, it would be necessary to compensate this loss with unreasonably large parameters that would be infeasible for practical use at large scale. Hence, while these previous works show that in principle the design of TLS 1.3 is secure in an asymptotic sense, they do not yet provide any useful concrete security guarantees for real-world parameters used in practice. In this work, we provide a new security proof for the cryptographic core of TLS 1.3 in the random oracle model, which reduces the security of TLS 1.3 tightly (that is, with constant security loss) to the (multi-user) security of its building blocks. For some building blocks, such as the symmetric record layer encryption scheme, we can then rely on prior work to establish tight security. For others, such as the RSA-PSS digital signature scheme currently used in TLS 1.3, we obtain at least a linear loss in the number of users, independent of the number of sessions, which is much easier to compensate with reasonable parameters. Our work also shows that by replacing the RSA-PSS scheme with a tightly secure scheme (e.g., in a future TLS version), one can obtain the first fully tightly secure TLS protocol. Our results enable a theoretically sound selection of parameters for TLS 1.3, even in large-scale settings with many users and sessions per user.

scholarly journals An Identity-Based Blind Signature Scheme Using Lattice with Provable Security

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Quanrun Li ◽  
Chingfang Hsu ◽  
Debiao He ◽  
Kim-Kwang Raymond Choo ◽  
Peng Gong
Keyword(s):  
Quantum Computer ◽  
Rapid Development ◽  
Random Oracle Model ◽  
Random Oracle ◽  
Mean Value ◽  
Blind Signature ◽  
Signature Scheme ◽  
Practical Applications ◽  
Universal Quantum ◽  
Identity Based

With the rapid development of quantum computing and quantum information technology, the universal quantum computer will emerge in the near decades with a very high probability and it could break most of the current public key cryptosystems totally. Due to the ability of withstanding the universal quantum computer’s attack, the lattice-based cryptosystems have received lots of attention from both industry and academia. In this paper, we propose an identity-based blind signature scheme using lattice. We also prove that the proposed scheme is provably secure in the random oracle model. The performance analysis shows that the proposed scheme has less mean value of sampling times and smaller signature size than previous schemes. Thus, the proposed scheme is more suitable for practical applications.

scholarly journals ID-based key-insulated signcryption with equality test in cloud computing

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Seth Alornyo ◽  
Kingsford Kissi Mireku ◽  
Mustapha Adamu Mohammed ◽  
Daniel Adu-Gyamfi ◽  
Michael Asante
Keyword(s):  
Cloud Computing ◽  
Random Oracle Model ◽  
Random Oracle ◽  
Harsh Environments ◽  
Secret Key ◽  
Secret Keys ◽  
Security Property ◽  
Equality Test ◽  
Chosen Ciphertext Attack ◽  
Chosen Message Attack

AbstractKey-insulated encryption reduces the problem of secret key exposure in hostile setting while signcryption cryptosystem attains the benefits of digitally signing a ciphertext and public key cryptosystem. In this study, we merge the primitives of parallel key-insulation cryptosystem and signcryption with equality test to construct ID-based parallel key-insulated signcryption with a test for equality (ID-PKSET) in cloud computing. The construction prevent data forgery, data re-play attacks and reduces the leakage of secret keys in harsh environments. Our scheme attains the security property of existential unforgeable chosen message attack (EUF-CMA) and indistinquishable identity chosen ciphertext attack (IND-ID-CCA2) using random oracle model.

Tighter Security Proofs for GPV-IBE in the Quantum Random Oracle Model

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Shuichi Katsumata ◽  
Shota Yamada ◽  
Takashi Yamakawa
Keyword(s):  
Random Oracle Model ◽  
Random Oracle ◽  
Security Proofs

Tighter Proofs of CCA Security in the Quantum Random Oracle Model

2019 ◽  
pp. 61-90 ◽  
Author(s):  
Nina Bindel ◽  
Mike Hamburg ◽  
Kathrin Hövelmanns ◽  
Andreas Hülsing ◽  
Edoardo Persichetti
Keyword(s):  
Random Oracle Model ◽  
Random Oracle
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