With the popularization of face recognition technology in IoT-Cloud, the problem of privacy leakage caused by it is becoming more and more serious. Although traditional privacy protection schemes can improve security to a certain extent, there is still a risk of data leakage when facing semi-trusted cloud servers. To this end, this paper proposes an anonymized face verification scheme for IoT convergence scenarios, which achieves real-time retrieval and secure matching of dense face features in virtual device copies by combining homomorphic encryption (CKKS) and privacy information retrieval (PIR) for anonymized face verification. The scheme ensures that the semi-trusted cloud server cannot obtain user-specific index information and matching results. Experiments show that the scheme’s verification accuracy in the ciphertext state on the LFW dataset is consistent with the plaintext, up to 97.06%, and can complete a privacy-protected anonymized facial verification process within seconds. The scheme is feasible in security demanding scenarios.

With the advent of the 5G era, online healthcare has rapidly developed, and medical efficiency has been greatly enhanced through medical data sharing. However, as cloud services are not fully trusted, users who have lost physical control of their data urgently require a provable data possession scheme to regularly verify the integrity of their outsourced data. Moreover, the scheme must protect the user’s real identity and the security of the data content. To meet these needs while overcoming issues such as complex certificate management, high operational costs, and the key escrow problem, scholars have proposed many certificateless provable data possession schemes. Among them, we analyze the ReCIP scheme which supports privacy preservation and efficient revocation, identify its limitations, and propose an enhanced ReCIP+ scheme tailored for medical data sharing. Under the assumption that the discrete logarithm problem and the computational Diffie–Hellman problem are hard, we formally prove the correctness and security of the ReCIP+ scheme. Furthermore, comparative evaluation demonstrates that the ReCIP+ scheme offers improved security and relatively lower computational costs compared to existing schemes.

With the increasing demand of consumers for food safety, the application of Internet of Things (IoT) in agriculture is more and more extensive, especially the use of technologies such as QR codes and sensors for food information traceability. However, the Internet of Things still faces challenges in ensuring the authenticity of food data transmission and the integrity of food anti-counterfeiting authentication, especially the traditional digital signature algorithm that the Internet of Things relies on is vulnerable to the security threat brought by future quantum computers. In order to solve this problem, we propose a domestic replacement solution for the post-quantum digital signature algorithm SPHINCS-α(an improvement of the standardized post-quantum digital signature scheme SPHINCS+), and use the chinese national standard cryptographic hash function Shang Mi 3 (SM3) to replace its underlying hash function. Finally, we conducted experiments, gave the benchmark test results under three security parameters, and compared the performance with the original scheme using SHA256 and Shake256 hash function. The results prove the feasibility of our method, although there is a small rate drop, but in exchange for a more secure domestic hash function. It provides strong support for the early deployment of post-quantum cryptography algorithm in the Internet of Things environment of sustainable agriculture and industry, and ensures the integrity of the Internet of Things data in the practice of sustainable agriculture.

Abstract The rapid development of new technologies such as artificial intelligence and big data analysis requires the simultaneous development of cloud computing technology. The application of IoT‐to‐cloud setting has been fully applied in various industry sectors, such as sensor‐cloud system which is composed of wireless sensor network and cloud computing technology. With the increasing amount and types of collected data, companies need to reduce the dimension of massive data in cloud servers for obtaining data analysis reports rapidly. Due to frequent cloud server data leaks, companies must adequately protect the privacy of some confidential data. To this end, we designed a dimension reduction method for ciphertext data in the sensor‐cloud system based on the CKKS encryption scheme, principal component analysis (PCA) and linear discriminant analysis (LDA) dimension reduction algorithm. As data cannot be directly calculated using traditional PCA and LDA algorithm after encryption, we add some interactive operations and iterative calculations to replace some steps in traditional algorithms. Finally, we select the classification dataset IRIS which is commonly used in machine learning, and screen out the best encryption and calculation parameters, and efficiently realize the dimension reduction method of ciphertext data through a large number of experiments.

Mobile cloud storage (MCS) provides clients with convenient cloud storage service. In this article, we propose an efficient, secure and privacy-preserving mobile cloud storage scheme, which protects the data confidentiality and privacy simultaneously, especially the access pattern. Specifically, we propose an oblivious selection and update (OSU) protocol as the underlying primitive of the proposed mobile cloud storage scheme. OSU is based on onion additively homomorphic encryption with constant encryption layers and enables the client to obliviously retrieve an encrypted data item from the cloud and update it with a fresh value by generating a small encrypted vector, which significantly reduces the client’s computation as well as the communication overheads. Compared with previous works, our presented work has valuable properties, such as fine-grained data structure (small item size), lightweight client-side computation (a few of additively homomorphic operations) and constant communication overhead, which make it more suitable for MCS scenario. Moreover, by employing the “verification chunks” method, our scheme can be verifiable to resist malicious cloud. The comparison and evaluation indicate that our scheme is more efficient than existing oblivious storage solutions with the aspects of client and cloud workloads, respectively.

Summary Outsourcing data to cloud servers is a popular service for data owners, however, how to check the integrity and freshness of the outsourced data is very challenge. Recently, Jin et al. proposed a cloud auditing protocol with full integrity and freshness support for cloud data, unfortunately in this article, we show their proposal is not secure. Concretely, the cloud servers can forge the authentication tag and thus has the ability to forge proof of data possession, which obviously invalidates their cloud auditing protocol. We also give a new cloud auditing protocol and analysis its security and performance. The results show our protocol is more efficient and secure.

With the advent of data outsourcing, how to efficiently verify the integrity of data stored at an untrusted cloud service provider (CSP) has become a significant problem in cloud storage. In 2019, Guo et al. proposed an outsourced dynamic provable data possession scheme with batch update for secure cloud storage. Although their scheme is very novel, we find that their proposal is not secure in this paper. The malicious cloud server has ability to forge the authentication labels, and thus it can forge or delete the user’s data but still provide a correct data possession proof. Based on the original protocol, we proposed an improved one for the auditing scheme, and our new protocol is effective yet resistant to attacks.

Public auditing protocol is crucial for the success of cloud computing, as it can ensure the outsourced data in cloud server are not tampered by attackers. Due to its importance, public auditing protocol has received considerable attention in the past years. In 2015, Liu et al. proposed a privacy-preserving public auditing protocol for regenerating-code-based cloud storage (IEEE Transactions on Information Forensics and Security, 10(7):1513-1528, 2015) and claimed it is secure under the considered security model. However, in this article, we will show that their protocol is not as secure as they claimed, i.e., the proxy delegated by the data owner can forge an authenticator for any data block, which obviously invalidates their protocol's security. We hope that by identifying the design flaw, similar weaknesses can be avoided in future protocol design.

Now, it is common for patients and medical institutions to outsource their data to cloud storage. This can greatly reduce the burden of medical information management and storage and improve the efficiency of the entire medical industry. In some cases, the group‐based cloud storage system is also very common to be used. For example, in an medical enterprise, the employees outsource the working documents to the cloud storage and share them to the colleagues. However, when the working documents are outsourced to the cloud servers, how to ensure their security is a challenge problem for they are not controlled physically by the data owners. In particular, the integrity of the outsourced data should be guaranteed. And the secure cloud auditing protocol is designed to solve this issue. Recently, a lightweight secure auditing scheme for shared data in cloud storage is proposed. Unfortunately, we find this proposal not secure in this paper. It’s easy for the cloud server to forge the authentication label, and thus they can delete all the outsourced data when the cloud server still provide a correct data possession proof, which invalidates the security of the cloud audit protocol. On the basis of the original security auditing protocol, we provide an improved one for the shared data, roughly analysis its security, and the results show our new protocol is secure.

Summary Outsourcing datum to the cloud servers is more and more popular for most data owners and enterprises. However, how to ensure the outsourced datum to be kept secure is very important. Especially, how to check the outsourced datum's integrity is a very challenge problem. Until now, there are many cryptographic protocols proposed to solve this problem, such as (dynamic) provable data position protocol, (dynamic) proof of retrievability protocol, etc. Recently, Tian et al proposed a dynamic‐hash‐table‐based public auditing scheme for secure cloud storage, which aims at simultaneously supporting secure dynamic data updating and secure public auditing for cloud storage. However, we find a security flaw in this protocol; concretely, the signature algorithm for the data blocks in their protocol is not secure; the cloud servers can easily modify the outsourced data blocks without detecting. Finally, we give a new protocol by using homomorphic tags based on their protocol and roughly analysis its security.

With more organizational and individual data owners storing their data in the cloud, there is a corresponding need to ensure that such outsourced data can be computed by the data owners or some authorized third parties. In other words, the cloud server performs the requested computation, and returns the computation result to the requesting party. Such a paradigm is referred to as outsourced computation in the literature. A challenge is how one can ensure the correctness of the returned result, and this has been extensively studied in the literature. For example, in 2017, Songet al. proposed a protocol for publicly verifiable computation of polynomials over outsourced data with multiple sources. However, we reveal that a core building block of their protocol allows an adversary to forge the signatures on the outsourced data. Hence, this invalidates the security of the protocol. We also point out their proposal is yet very interesting and useful, only a little improvement can strengthen their proposal to be secure.

Summary In the IoT setting, many resource constrained devices outsource their collected data to the Cloud. To ensure the outsourced data has not been lost, these devices need some mechanism to check the integrity of their data. Furthermore, in some settings, ad hoc devices need to act as a group, and in this group, any member may require to verify the integrity of outsourced cloud storage. Aiming at solving this problem, in AISACCS'15, first proposed the concept of group‐based proofs of storage (GPoS). In GPoS, a group manager can authorize data owners as group members, and then these group members can outsource files to the cloud storage server; later, each member can verify the integrity of the outsourced cloud storage. They also give a concrete construction of GPoS. Unfortunately, in this paper, we find their scheme is not secure. Recently, also proposed a dynamic group‐based integrity auditing protocol for outsrouced cloud storage; we also show their scheme is not secure either. Finally, we give an improved scheme and roughly analysis to its security and performance.

Summary Private set intersection (PSI) protocols enable 2 parties to compute the intersection of their inputs without compromising anything about the datasets beyond the intersection. With the advent of cloud computing, outsourcing computation has been attracted wide range of attention from research community and applied widely in the industry. The cloud computing allows resources restrained devices to outsource their expensive computation to the cloud. Based on Abadi's O‐PSI, we present a variant of delegated private set intersection protocol secure in the semi‐honest model under RSA assumption, and we also give an efficient and secure outsourcing computation algorithm for RSA cryptosystem. Depending on this algorithm, we transform a variant of delegated private set intersection protocol into an improved outsourced one. It enables the clients only to perform simple modular multiplication for computing what they want during the execution of protocol. Besides, the variant of delegated protocol can be easily extended to multiple clients. Compared with the state of the art, our proposed protocol has great advantage in efficiency. We finally evaluate these protocols and prove their security in the semi‐honest model.

The decline in genome sequencing costs has widened the population that can afford its cost and has also raised concerns about genetic privacy. Kim et al. present a practical solution to the scenario of secure searching of gene data on a semitrusted business cloud. However, there are three errors in their scheme. We have made three improvements to solve these three errors. (1) They truncate the variation encodings of gene to 21 bits, which causes LPCE error and more than 5% of the entries in the database cannot be queried integrally. We decompose these large encodings by 44 bits and deal with the components, respectively, to avoid LPCE error. (2) We abandon the hash function used in Kim’s scheme, which may cause HCE error with a probability of 2-22 and decompose the position encoding of gene into three parts with the basis 211 to avoid HCE error. (3) We analyze the relationship between the parameters and the CCE error and specify the condition that parameters need to satisfy to avoid the CCE error. Experiments show that our scheme can search all entries, and the probability of searching error is reduced to less than 2-37.4 .

Reverse unknown protocol's hidden behavior has played an important role in the field of network security. The proposed work takes the captured messages and the binary code that implement the protocol both as the studied object. Dynamic Taint Analysis combined with Static Analysis is used for protocol analyzing. Firstly, monitor and analyze the process of protocol program parses the message in the virtual platform HiddenDisc prototype system developed by ourselves, record the protocol's public behavior, then based on our proposed Hidden Behavior Perception and Mining algorithm, static analyze the protocol's hidden behavior trigger conditions and hidden behavior instruction sequences. According to the hidden behavior trigger conditions, new protocol messages with the sensitive information are generated, and the hidden behaviors are executed by dynamic triggering. HiddenDisc prototype system can sense, trigger and analyze the protocol's hidden behaviors. According to the statistical analysis results, we propose the evaluation method of Protocol Execution Security. The experimental results show that the present method can accurately mining the protocol's hidden behaviors, and can evaluate unknown protocol's execution security.

This paper presents an identity-based dynamic authenticated group key agreement (DAGKA) protocol with following advantages. The algorithms of Setup and Join has only one round communication. There is no message exchange among members in Leave algorithm. Joining members cannot know previous session keys and leaving members cannot know future session keys. Its AKE-security is proved under Decisional Bilinear Diffie-Hellman (DBDH) assumption. The protocol can resist key control attack and has forward security.

Rapid development of cloud storage services produces a tremendous amount of user data outsourcing to cloud servers. Therefore, it is easy to generate data multi-replica, which is able to improve data availability and users' experience. However, when the management of data is poor, the sensitive information will be disclosed more easily. This may bring serious security and privacy challenges for both user's data and its multi-replica in cloud environment. In order to tackle the above issues, in this paper, we propose a multi-replica associated deleting scheme (MADS) in cloud environment. We first introduce a replica associated model to organize all of data replicas among different cloud servers. Furthermore, we propose the MADS scheme which is consists of data storage algorithm, replica generation algorithm, replica deletion and feedback algorithm. Finally, we employ Amazon S3 to implement MADS and the results indicate that the proposed scheme is available and effective.

In Informatica 32 (2008), Ren and Gu proposed an anonymous hierarchical identity based encryption scheme based on the q-ABDHE problem with full security in the standard model. Later in Indocrypt'08, they proposed another secure hierarchical identity based encryption scheme based on the q-TBDHE problem with full security in the standard model. They claimed that their schemes have short parameters, high efficiency and tight reduction. However, in this paper we give attacks to show their schemes are not secure at all. Concretely, from any first level private key, the adversary can easily derive a “private key” which can decrypt any ciphertexts for the target identity. That is to say, a query on any first level identity is enough to decrypt any ciphertext in the system.

At Pairing'07, Matsuo proposed two proxy re-encryption schemes: proxy re-encryption fromCBE to IBE and IBE to IBE. Now both schemes have been standardized by P1363.3workgroup. In this paper, we show that their identity based proxy re-encryption scheme is insecure. We give two attacks to this scheme. The first attack shows that the proxy can re-encrypt any IBE user's ciphertext to be the delegatee's ciphertext. The second attack implies that, if the proxy colludes with any delegatee, the proxy and this delegatee can derive any other IBE user's secret key.

The concept of proxy re-cryptography comes from the work of Blaze, Bleumer, and Strauss in 1998. The goal of proxy re-encryption is to securely enable the re-encryption of ciphertexts from one key to another, without relying on trusted parties. In 2007, Matsuo proposed the concept of four types of proxy re-encryption schemes: CBE to CBE, IBE to CBE, CBE to IBE and IBE to IBE. Now CBE to IBE and IBE to IBE proxy re-encryption schemes are being standardized by IEEEP1363.3 working group. One feature of their schemes is that they are all based on BB1 identity based encryption. We reconsider the problem of constructing proxy re-encryption based on SK identity based encryption. Surprisingly, if we consider the help of PKG, then it is easy to construct proxy re-encryption based on SK identity based encryption. Interestingly , our proxy re-encryption scheme even can achieve CCA2 secure, which makes it is unique.

First we revisit three (BGLS, MBGLS and GZZ) verifiably encrypted signature schemes. We find that they are all not strong unforgeable. We remark that the notion of existential unforgeable is not sufficient for fair exchange protocols in most circumstances. So we propose three new (NBGLS, MBGLS and NGZZ) verifiably encrypted signature schemes which are strong unforgeable. Also we reconsider other two (ZSS and CA) verifiably encrypted signature schemes we find that they both cannot resist replacing public key attack. So we strongly suggest that strong unforgeable for verifiably encrypted signature be a better notion than existential unforgeable and checking adjudicator knowing its private key is a necessary step for secure verifiably encrypted signature scheme.