scholarly journals A multi-authority approach to various predicate encryption types

2019 ◽  
Vol 88 (2) ◽  
pp. 363-390
Author(s):  
Tim van de Kamp ◽  
Andreas Peter ◽  
Willem Jonker
Keyword(s):  
Admissible Pair ◽  
Random Oracle Model ◽  
Random Oracle ◽  
Encryption Scheme ◽  
Encoding Scheme ◽  
Decentralized System ◽  
Conversion Algorithm ◽  
Encryption Schemes ◽  
Generic Construction ◽  
Predicate Encryption

Abstract We propose a generic construction for fully secure decentralized multiauthority predicate encryption. In such multiauthority predicate encryption scheme, ciphertexts are associated with one or more predicates from various authorities and only if a user has a set of decryption keys that evaluates all predicates to true, the user is able to recover the message. In our decentralized system, anyone can create a new authority and issue decryption keys for their own predicates. We introduce the concept of a multi-authority admissible pair encoding scheme and, based on these encodings, we give a generic conversion algorithm that allows us to easily combine various predicate encryption schemes into a multi-authority predicate encryption variant. The resulting encryption schemes are proven fully secure under standard subgroup decision assumptions in the random oracle model. Finally, by instantiating several concrete multi-authority admissible pair encoding schemes and applying our conversion algorithm, we are able to create a variety of novel multi-authority predicate encryption schemes.

Secure Key Storage and Access Delegation Through Cloud Storage

2020 ◽  
Vol 11 (4) ◽  
pp. 45-64
Author(s):  
Bharati Mishra ◽  
Debasish Jena ◽  
Ramasubbareddy Somula ◽  
S. Sankar
Keyword(s):  
Key Management ◽  
Cloud Storage ◽  
Random Oracle Model ◽  
Random Oracle ◽  
Key Generation ◽  
Encryption Scheme ◽  
Lightweight Cryptography ◽  
Encryption Schemes ◽  
Client Side ◽  
Cloud User

Cloud storage is gaining popularity to store and share files. To secure the files, cloud storage providers supply client interfaces with the facility to encrypt the files and upload them into the cloud. When client-side encryption is done, the onus of key management lies with the cloud user. Public key proxy re-encryption mechanisms can be used to distribute the key among stakeholders of the file. However, clients use low powered devices like mobile phones to share their files. Lightweight cryptography operations are needed to carry out the encryption operations. Ring-LWE-based encryption scheme meets this criterion. In this work, a proxy re-encryption scheme is proposed to distribute the file key. The scheme is proved CCA secure under Ring-LWE assumption in the random oracle model. The performance of the scheme is compared with the existing proxy re-encryption schemes which are observed to show better performance for re-encryption and re-key generation.

scholarly journals Predicate signatures from pair encodings via dual system proof technique

2019 ◽  
Vol 13 (3-4) ◽  
pp. 197-228
Author(s):  
Mridul Nandi ◽  
Tapas Pandit
Keyword(s):  
Dual System ◽  
Regular Languages ◽  
Adaptive Model ◽  
Proof Technique ◽  
Encoding Scheme ◽  
Constant Size ◽  
Generic Framework ◽  
Generic Construction ◽  
Key Policy ◽  
Predicate Encryption

Abstract Recently, Attrapadung (Eurocrypt 2014) proposed a generic framework for fully (adaptively) secure predicate encryption (PE) based on a new primitive, called pair encodings. The author shows that if the underlying pair encoding scheme is either perfectly secure or computationally (doubly-selectively) secure, then the PE scheme will be fully secure. Although the pair encodings were solely introduced for PE, we show that these can also be used to construct predicate signatures, a signature analogue of PE. More precisely, we propose a generic construction of predicate signature (PS) from pair encoding schemes. Our construction provides unconditional signer privacy, and unforgeability in the adaptive model. Thereafter, we instantiate many PS schemes with new results, e.g., the first practical PS schemes for regular languages, the first attribute-based signature (ABS) scheme with constant-size signatures in the adaptive model, unbounded ABS with large universes in key-policy flavor, etc.

Double-authentication-preventing signatures in the standard model

2021 ◽  
pp. 1-36
Author(s):  
Dario Catalano ◽  
Georg Fuchsbauer ◽  
Azam Soleimanian
Keyword(s):  
Standard Model ◽  
Random Oracle Model ◽  
Random Oracle ◽  
Polynomial Size ◽  
The Standard Model ◽  
Generic Construction ◽  
Self Enforcement ◽  
Digital Signature Scheme ◽  
Chameleon Hash ◽  
Main Construction

A double-authentication preventing signature (DAPS) scheme is a digital signature scheme equipped with a self-enforcement mechanism. Messages consist of an address and a payload component, and a signer is penalized if she signs two messages with the same addresses but different payloads. The penalty is the disclosure of the signer’s signing key. Most of the existing DAPS schemes are proved secure in the random oracle model (ROM), while the efficient ones in the standard model only support address spaces of polynomial size. We present DAPS schemes that are efficient, secure in the standard model under standard assumptions and support large address spaces. Our main construction builds on vector commitments (VC) and double-trapdoor chameleon hash functions (DCH). We also provide a DAPS realization from Groth–Sahai (GS) proofs that builds on a generic construction by Derler et al., which they instantiate in the ROM. The GS-based construction, while less efficient than our main one, shows that a general yet efficient instantiation of DAPS in the standard model is possible. An interesting feature of our main construction is that it can be easily modified to guarantee security even in the most challenging setting where no trusted setup is provided. To the best of our knowledge, ours seems to be the first construction achieving this in the standard model.

scholarly journals Security of signature schemes in the presence of key-dependent messages

2010 ◽  
Vol 47 (1) ◽  
pp. 15-29
Author(s):  
Madeline González Muñiz ◽  
Rainer Steinwndt
Keyword(s):  
Random Oracle Model ◽  
Random Oracle ◽  
Signature Scheme ◽  
Forward Security ◽  
Signature Schemes ◽  
Encryption Schemes ◽  
Time Signature ◽  
Made In

Abstract In recent years, quite some progress has been made in understand- ing the security of encryption schemes in the presence of key-dependent plaintexts. Here, we motivate and explore the security of a setting, where an adversary against a signature scheme can access signatures on key-dependent messages. We propose a way to formalize the security of signature schemes in the pres- ence of key-dependent signatures (KDS). It turns out that the situation is quite different from key-dependent encryption: already to achieve KDS-security under non-adaptive chosen message attacks, the use of a stateful signing algorithm is inevitable-even in the random oracle model. After discussing the connection be- tween key-dependent signing and forward security, we present a compiler to lift any EUF-CMA secure one-time signature scheme to a forward secure signature scheme offering KDS-CMA security.

scholarly journals Efficient Certificateless Anonymous Multi-Receiver Encryption Scheme without Bilinear Parings

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Ronghai Gao ◽  
Jiwen Zeng ◽  
Lunzhi Deng
Keyword(s):  
Mobile Devices ◽  
Security Analysis ◽  
Mobile Network ◽  
Random Oracle Model ◽  
Random Oracle ◽  
Bilinear Pairing ◽  
Internet Technology ◽  
Security And Privacy ◽  
Encryption Scheme ◽  
The Troubles

With the growing development of Internet technology and popularization of mobile devices, we easily access the Internet anytime and anywhere by mobile devices. It has brought great convenience for our lives. But it brought more challenges than traditional wired communication, such as confidentiality and privacy. In order to improve security and privacy protection in using mobile network, numerous multi-receiver identity-based encryption schemes have been proposed with bilinear pairing and probabilistic hap-to-point (HTP) function. To address the troubles of private key escrow in multi-receiver encryption scheme based on ID-PKC, recently, some certificateless anonymous multi-receiver encryption (CLAMRE) schemes are introduced. But previous CLAMRE schemes using the bilinear pairing are not suitable to mobile device because the use of bilinear pairing and probabilistic hash-to-point (HTP) function results in expensive operation costs in encryption or decryption. In this paper, we propose an efficient CLAMRE scheme using elliptic curve cryptography (ECC) without bilinear pairing and HTP hash function. Since our scheme does not use bilinear pairing and HTP operation during the encryption and decryption process, the proposed CLAMRE scheme has much less computation cost than the latest CLAMRE schemes. Performance analysis shows that runtime of our scheme is much less when the sender generates ciphertext, compared with existing schemes. Security analysis shows proposed CLAMRE scheme provides confidentiality of message and receiver anonymity under the random oracle model with the difficulties of decision Diffie-Hellman problem and against the adversaries defined in CL-PKC system.

scholarly journals Compiled Constructions towards Post-Quantum Group Key Exchange: A Design from Kyber

Mathematics ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1853
Author(s):  
José Ignacio Escribano Pablos ◽  
María Isabel González Vasco ◽  
Misael Enrique Marriaga ◽  
Ángel Luis Pérez del Pozo
Keyword(s):  
Random Oracle Model ◽  
Building Blocks ◽  
Random Oracle ◽  
Key Exchange ◽  
Encryption Scheme ◽  
Secret Key ◽  
Key Exchange Protocol ◽  
Group Key ◽  
Group Key Exchange ◽  
Starting Point

A group authenticated key exchange (GAKE) protocol allows a set of parties belonging to a certain designated group to agree upon a common secret key through an insecure communication network. In the last few years, many new cryptographic tools have been specifically designed to thwart attacks from adversaries which may have access to (different kinds of) quantum computation resources. However, few constructions for group key exchange have been put forward. Here, we propose a four-round GAKE which can be proven secure under widely accepted assumptions in the Quantum Random Oracle Model. Specifically, we integrate several primitives from the so-called Kyber suite of post-quantum tools in a (slightly modified) compiler from Abdalla et al. (TCC 2007). More precisely, taking as a starting point an IND-CPA encryption scheme from the Kyber portfolio, we derive, using results from Hövelmanns et al. (PKC 2020), a two-party key exchange protocol and an IND-CCA encryption scheme and prove them fit as building blocks for our compiled construction. The resulting GAKE protocol is secure under the Module-LWE assumption, and furthermore achieves authentication without the use of (expensive) post-quantum signatures.

Circular Transitivity of a Bidirectional Proxy Re-Encryption Scheme

2013 ◽  
Vol 321-324 ◽  
pp. 2639-2642
Author(s):  
Xiao Jing Hong ◽  
Bin Wang
Keyword(s):  
Random Oracle Model ◽  
Random Oracle ◽  
Formal Definition ◽  
Encryption Scheme ◽  
Cdh Assumption ◽  
Definition Of

The concept of proxy re-encryption (PRE) was first introduced by Blaze et al. Since then several CCA secure PRE schemes have been presented. Weng et al. proposed a non-transitive bidirectional PRE scheme without pairings and proved that their scheme to be PRE-CCA secure in the random oracle model under the CDH assumption. However, we show that Weng et als non-transitive scheme is still transitive under the formal definition of non-transitivity presented in this paper. Moreover, the transitivity of Weng et al.s scheme also implies that it is not PRE-CCA secure.

scholarly journals Group Signatures with Message-Dependent Opening: Formal Definitions and Constructions

2019 ◽  
Vol 2019 ◽  
pp. 1-36 ◽  
Author(s):  
Keita Emura ◽  
Goichiro Hanaoka ◽  
Yutaka Kawai ◽  
Takahiro Matsuda ◽  
Kazuma Ohara ◽  
...  
Keyword(s):  
Random Oracle Model ◽  
Random Oracle ◽  
Group Signature ◽  
Signature Scheme ◽  
Identity Based Encryption ◽  
Group Signatures ◽  
The Standard Model ◽  
Formal Definitions ◽  
Generic Construction ◽  
Identity Based

This paper introduces a new capability for group signatures called message-dependent opening. It is intended to weaken the high trust placed on the opener; i.e., no anonymity against the opener is provided by an ordinary group signature scheme. In a group signature scheme with message-dependent opening (GS-MDO), in addition to the opener, we set up an admitter that is not able to extract any user’s identity but admits the opener to open signatures by specifying messages where signatures on the specified messages will be opened by the opener. The opener cannot extract the signer’s identity from any signature whose corresponding message is not specified by the admitter. This paper presents formal definitions of GS-MDO and proposes a generic construction of it from identity-based encryption and adaptive non-interactive zero-knowledge proofs. Moreover, we propose two specific constructions, one in the standard model and one in the random oracle model. Our scheme in the standard model is an instantiation of our generic construction but the message-dependent opening property is bounded. In contrast, our scheme in the random oracle model is not a direct instantiation of our generic construction but is optimized to increase efficiency and achieves the unbounded message-dependent opening property. Furthermore, we also demonstrate that GS-MDO implies identity-based encryption, thus implying that identity-based encryption is essential for designing GS-MDO schemes.

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