Reversible Data Hiding Algorithm in Encrypted Images Based on Adaptive Median Edge Detection and Ciphertext-Policy Attribute-Based Encryption

With the rapid advancement of cloud computing technology,reversible data hiding algorithms in encrypted images(RDH-EI)have developed into an important field of study concentrated on safeguarding privacy in distributed cloud environments.However,existing algorithms often suffer from low embedding capacities and are inadequate for complex data access scenarios.To address these challenges,this paper proposes a novel reversible data hiding algorithm in encrypted images based on adaptive median edge detection(AMED)and ciphertext-policy attributebased encryption(CP-ABE).This proposed algorithm enhances the conventional median edge detection(MED)by incorporating dynamic variables to improve pixel prediction accuracy.The carrier image is subsequently reconstructed using the Huffman coding technique.Encrypted image generation is then achieved by encrypting the image based on system user attributes and data access rights,with the hierarchical embedding of the group’s secret data seamlessly integrated during the encryption process using the CP-ABE scheme.Ultimately,the encrypted image is transmitted to the data hider,enabling independent embedding of the secret data and resulting in the creation of the marked encrypted image.This approach allows only the receiver to extract the authorized group’s secret data,thereby enabling fine-grained,controlled access.Test results indicate that,in contrast to current algorithms,the method introduced here considerably improves the embedding rate while preserving lossless image recovery.Specifically,the average maximum embedding rates for the(3,4)-threshold and(6,6)-threshold schemes reach 5.7853 bits per pixel(bpp)and 7.7781 bpp,respectively,across the BOSSbase,BOW-2,and USD databases.Furthermore,the algorithm facilitates permission-granting and joint-decryption capabilities.Additionally,this paper conducts a comprehensive examination of the algorithm’s robustness using metrics such as image correlation,information entropy,and number of pixel change rate(NPCR),confirming its high level of security.Overall,the algorithm can be applied in a multi-user and multi-level cloud service environment to realize the secure storage of carrier images and secret data.

A Generic Construction of Ciphertext-Policy Attribute- Based Encryption Supporting Attribute Revocation

Attribute-based encryption is drawing more attention with its inherent attractive properties which are potential to be widely used in the newly developing cloud computing. However, one of the main obstacles for its application is how to revoke the attributes of the users, though some ABE schemes have realized revocation, they mostly focused on the user revocation that revokes the user＇s whole attributes, or attribute revocation under the indirect revocation model such that all the users＇ private keys will be affected by the revocation. In this paper, we define the model of CP-ABE supporting the attribute revocation under the direct revocation model, in which the revocation list is embed in the ciphertext and none of the users＇ private keys will be affected by the revocation process. Then we propose a generic construction, and prove its security with the decision q-BDHE assumption.

An Efficient Ciphertext-Policy Attribute-Based Encryption Scheme with Policy Update

Ciphertext-policy attribute-based encryption(CP-ABE)is a promising cryptographic solution to the problem for enforcing fine-grained access control over encrypted data in the cloud.However,when applying CP-ABE to data outsourcing scenarios,we have to address the challenging issue of policy updates because access control elements,such as users,attributes,and access rules may change frequently.In this paper,we propose a notion of access policy updatable ciphertext-policy attribute-based encryption(APU-CP-ABE)by combining the idea of ciphertext-policy attribute-based key encapsulation and symmetric proxy re-encryption.When an access policy update occurs,data owner is no longer required to download any data for re-encryption from the cloud,all he needs to do is generate a re-encryption key and produce a new encapsulated symmetric key,and then upload them to the cloud.The cloud server executes re-encryption without decryption.Because the re-encrypted ciphertext is encrypted under a completely new key,users cannot decrypt data even if they keep the old symmetric keys or parts of the previous ciphertext.We present an APU-CP-ABE construction based on Syalim et al.’s[Syalim,Nishide and Sakurai(2017)]improved symmetric proxy re-encryption scheme and Agrawal et al.’s[Agrawal and Chase(2017)]attribute-based message encryption scheme.It requires only 6 bilinear pairing operations for decryption,regardless of the number of attributes involved.This makes our construction particularly attractive when decryption is time-critical.

Hidden Hierarchy Based on Cipher-Text Attribute Encryption for IoT Data Privacy in Cloud

Most research works nowadays deal with real-time Internetof Things (IoT) data. However, with exponential data volume increases,organizations need help storing such humongous amounts of IoT data incloud storage systems. Moreover, such systems create security issues whileefficiently using IoT and Cloud Computing technologies. Ciphertext-Policy Attribute-Based Encryption (CP-ABE) has the potential to make IoT datamore secure and reliable in various cloud storage services. Cloud-assisted IoTssuffer from two privacy issues: access policies (public) and super polynomialdecryption times (attributed mainly to complex access structures). We havedeveloped a CP-ABE scheme in alignment with a Hidden HierarchyCiphertext-Policy Attribute-Based Encryption (HH-CP-ABE) access structure embedded within two policies, i.e., public policy and sensitive policy.In this proposed scheme, information is only revealed when the user’sinformation is satisfactory to the public policy. Furthermore, the proposedscheme applies to resource-constrained devices already contracted tasks totrusted servers (especially encryption/decryption/searching). Implementingthe method and keywords search resulted in higher access policy privacy andincreased security. The new scheme introduces superior storage in comparisonto existing systems (CP-ABE, H-CP-ABE), while also decreasing storage costsin HH-CP-ABE. Furthermore, a reduction in time for key generation canalso be noted.Moreover, the scheme proved secure, even in handling IoT datathreats in the Decisional Bilinear Diffie-Hellman (DBDH) case.

A Verifiable Trust-Based CP-ABE Access Control Scheme for Cloud-Assisted Renewable Energy Systems

Renewable Energy Systems(RES)provide a sustainable solution to climate warming and environmental pollution by enhancing stability and reliability through status acquisition and analysis on cloud platforms and intelligent processing on edge servers(ES).However,securely distributing encrypted data stored in the cloud to terminals that meet decryption requirements has become a prominent research topic.Additionally,managing attributes,including addition,deletion,and modification,is a crucial issue in the access control scheme for RES.To address these security concerns,a trust-based ciphertext-policy attribute-based encryption(CP-ABE)device access control scheme is proposed for RES(TB-CP-ABE).This scheme effectivelymanages the distribution and control of encrypted data on the cloud through robust attribute key management.By introducing trust management mechanisms and outsourced decryption technology,the ES system can effectively assess and manage the trust worthiness of terminal devices,ensuring that only trusted devices can participate in data exchange and access sensitive information.Besides,the ES system dynamically evaluates trust scores to set decryption trust thresholds,thereby regulating device data access permissions and enhancing the system’s security.To validate the security of the proposed TB-CP-ABE against chosen plaintext attacks,a comprehensive formal security analysis is conducted using the widely accepted random oraclemodel under the decisional q-Bilinear Diffie-Hellman Exponent(q-BDHE)assumption.Finally,comparative analysis with other schemes demonstrates that the TB-CP-ABE scheme cuts energy/communication costs by 43%,and scaleswell with rising terminals,maintaining average latency below 50ms,ensuring real-time service feasibility.The proposed scheme not only provides newinsights for the secure management of RES but also lays a foundation for future secure energy solutions.

车载社交网中基于密文属性加密的车队车辆数据共享方案

针对车载社交网(VSN)中车队车辆数据共享过程中存在的隐私泄露问题,提出一种基于密文属性的加密方案。利用基于属性的加密技术,保证仅授权的车辆可访问数据,防止车队车辆数据共享过程中发生隐私泄露;针对车队车辆数据共享时生成访问策略时间开销大、数据共享效率低的问题,通过构造访问树实现对访问策略的设计,利用路侧单元将访问树转化为访问矩阵,实现访问策略的快速生成。仿真分析结果表明,该方案能够实现对VSN中车队车辆的数据安全共享,所构建的访问策略生成方案能够有效降低车辆的计算开销。

Ciphertext-Policy Attribute-Based Encryption for General Circuits from Bilinear Maps

In this paper, we present the first ciphertext-policy attribute-based encryption （CP-ABE） scheme for polynomial-size general circuits based on bilinear maps which is more suitable for practical use and more efficient than multilinear maps. Our scheme uses a top-down secret sharing and FANOUT gate to resist the ＂backtracking attack＂ which is the main barrier expending access tree to general circuit. In the standard model, selective security of our scheme is proved. Comparing with current scheme for general circuits from bilinear maps, our work is more efficient.

基于属性基加密的区块链隐私保护与访问控制方法

区块链中所有节点都保存相同样本,随着区块链技术的广泛应用,区块链隐私保护与访问控制问题日益突出。文章基于多授权中心的属性基加密算法提出了面向区块链的隐私保护与访问控制方案。多授权中心可以由区块链中的权威节点轮值担任,有效解决了单一授权中心权限过大的问题。采用该方案后,所有数据采用属性基加密算法加密后保存在区块链中,只有属性满足访问控制策略的用户才能成功解密数据,从而实现区块链中的隐私保护与访问控制。

基于属性加密的数据共享管理研究

数据在共享和使用中面临着恶意攻击、供应链漏洞、安全产品缺陷、技术人员窃取等安全威胁.采用认证网关和密码机对用户身份进行认证,并对数据进行机密性完整性保护,能够增加安全性.但还存在内部威胁,如管理员被收买或内部终端被黑客控制,绕过安全防护机制.针对这些威胁,提出了基于SM9属性加密封装密钥,实现数据共享应用中不出现明文数据、有效应对系统管理员窃密等内部威胁.

A Hierarchical Attribute-Based Encryption Scheme

According to the relation of an attribute set and its subset,the author presents a hierarchical attribute-based encryption scheme in which a secret key is associated with an attribute set.A user can delegate the private key corresponding to any subset of an attribute set while he has the private key corresponding to the attribute set.Moreover,the size of the ciphertext is constant,but the size of private key is linear with the order of the attribute set in the hierarchical attribute-based encryption scheme.Lastly,we can also prove that this encryption scheme meets the security of IND-sSETCPA in the standard model.

Attribute-based encryption resilient to continual auxiliary leakage with constant size ciphertexts

For leakage-resilient ciphertext-policy attribute-based encryption （CP-ABE） at present, the size of the ciphertexts in most of them relies on the number of attributes. How to overcome this shortcoming is a challenge problem. Based on the Goldreich-Levin theorem and dual system encryption, an efficient CP-ABE scheme with constant size ciphertexts is proposed in this paper. It can tolerate leakage on master secret key and attribute-based secret keys with auxiliary inputs. Furthermore, the proposed scheme can be realized as resilience against continual leakage if keys are periodically updated. Under some static assumptions instead of other strong assumptions, the introduced scheme achieves adaptively security in the standard model.