• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.7-13
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• 2017

In recent years, cloud computing technology has been socially emerged that provides services remotely as various devices are used. However, there are increasing attempts by some users to provide cloud computing services with malicious intent. In this paper, we propose a property - based multi - level hierarchical approach to facilitate authentication access for users accessing servers in cloud environment. The proposed method improves the security efficiency as well as the server efficiency by hierarchically distributing a set of attribute values by replacing the order of the user 's attribute values in the form of bits according to a certain rule. In the performance evaluation, the proposed method shows that the accuracy of authentication according to the number of attributes is higher than that of the existing method by an average of 15.8% or more, and the authentication delay time of the server is decreased by 10.7% on average. As the number of attributes increases, the average overhead change is 8.5% lower than that of the conventional method.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.981-992
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• 2004

The established NEIS has a lot of problems in the management of security. It does not realize access control in following authority because it only uses PKI certification in user certification and the use of central concentration DBMS and plain text are increased hacking possibility in NEIS. So, This paper suggests a new NEIS for the secure management of data and authority certification. First, we suggest the approached authority in AC pf PMI and user certification in following the role, RBAC. Second, we realize DB encryption plan by digital signature for the purpose of preventig DB hacking. Third, we suggest SQL counterfeit prevention by one-way hash function and safe data transmission per-formed DB encryption by digital signature.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7C
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• pp.667-673
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• 2007

In order to provide the efficient personalized services, the organizations and the companies collect and manage the personal information. The stored data have some slight differences among each subject. Even though the same attribute information leaks out, the personal privacy violation is different according to personal sensitivity. However, currently the organizations or the companies protect all the information as the same level. This paper reflects the sensitive attribute information of the information subject to each personal policy by the encrypting techniques. And then we propose a policy-based access control mechanism for the personal information which strictly prevents unauthorized information users from illegally accessing the personal information. In the proposed mechanism, the individuals' personal information which is encrypted with different keys is stored into the database. For the access control, information subjects set up their own access control policy for their sensitive personal information. Then it is possible to control the information access by providing the information to the information users according to personal and organizational privacy policy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2394-2406
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• 2016

ABE has become an effective tool for data protection in cloud computing. However, since users possessing the same attributes share the same private keys, there exist some malicious users exposing their private keys deliberately for illegal data sharing without being detected, which will threaten the security of the cloud system. Such issues remain in many current ABE schemes since the private keys are rarely associated with any user specific identifiers. In order to achieve user accountability as well as provide key exposure protection, in this paper, we propose a key-insulated ciphertext policy attribute based encryption with key exposure accountability (KI-CPABE-KEA). In our scheme, data receiver can decrypt the ciphertext if the attributes he owns match with the self-centric policy which is set by the data owner. Besides, a unique identifier is embedded into each user's private key. If a malicious user exposes his private key for illegal data sharing, his identity can be exactly pinpointed by system manager. The key-insulation mechanism guarantees forward and backward security when key exposure happens as well as provides efficient key updating for users in the cloud system. The higher efficiency with proved security make our KI-CPABE-KEA more appropriate for secure data sharing in cloud computing.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.3
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• pp.499-510
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• 2023

Recently, an intelligent and advanced cyber attack attacks a computer network of a public institution using a file containing malicious code or leaks information, and the damage is increasing. Even in public institutions with various information protection systems, known attacks can be detected, but unknown dynamic and encryption attacks can be detected when existing signature-based or static analysis-based malware and ransomware file detection methods are used. vulnerable to The detection method proposed in this study extracts the detection result data of the system that can detect malicious code and ransomware among the information protection systems actually used by public institutions, derives various attributes by combining them, and uses a machine learning classification algorithm. Results are derived through experiments on how the derived properties are classified and which properties have a significant effect on the classification result and accuracy improvement. In the experimental results of this paper, although it is different for each algorithm when a specific attribute is included or not, the learning with a specific attribute shows an increase in accuracy, and later detects malicious code and ransomware files and abnormal behavior in the information protection system. It is expected that it can be used for property selection when creating algorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.10
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• pp.4136-4156
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• 2020

Recently, data can be safely shared or stored using the infrastructure of cloud computing in various fields. However, issues such as data security and privacy affect cloud environments. Thus, a variety of security technologies are required, one of them is security technology using CP-ABE. Research into the CP-ABE scheme is currently ongoing, but the existing CP-ABE schemes can pose security threats and are inefficient. In terms of security, the CP-ABE approach should be secure against user collusion attacks and masquerade attacks. In addition, in a dynamic cloud environment where users are frequently added or removed, they must eliminate user access when they leave, and so users will not be able to access the cloud after removal. A user who has left should not be able to access the cloud with the existing attributes, secret key that had been granted. In addition, the existing CP-ABE scheme increases the size of the ciphertext according to the number of attributes specified by the data owner. This leads to inefficient use of cloud storage space and increases the amount of operations carried out by the user, which becomes excessive when the number of attributes is large. In this paper, CP-ABE access control is proposed to block access of withdrawn users in dynamic cloud environments. This proposed scheme focuses on the revocation of the attributes of the withdrawn users and the output of a ciphertext of a constant-size, and improves the efficiency of the user decryption operation through outsourcing.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.2
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• pp.565-586
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• 2022

Cloud storage's elastic expansibility not only provides flexible services for data owners to store their data remotely, but also reduces storage operation and management costs of their data sharing. The data outsourced remotely in the storage space of cloud service provider also brings data security concerns about data integrity. Data integrity verification has become an important technology for detecting the integrity of remote shared data. However, users without data access rights to verify the data integrity will cause unnecessary overhead to data owner and cloud service provider. Especially malicious users who constantly launch data integrity verification will greatly waste service resources. Since data owner is a consumer purchasing cloud services, he needs to bear both the cost of data storage and that of data verification. This paper proposes a verification control algorithm in data integrity verification for remotely outsourced data. It designs an attribute-based encryption verification control algorithm for multiple verifiers. Moreover, data owner and cloud service provider construct a common access structure together and generate a verification sentinel to verify the authority of verifiers according to the access structure. Finally, since cloud service provider cannot know the access structure and the sentry generation operation, it can only authenticate verifiers with satisfying access policy to verify the data integrity for the corresponding outsourced data. Theoretical analysis and experimental results show that the proposed algorithm achieves fine-grained access control to multiple verifiers for the data integrity verification.