• Convergence Security Journal
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• v.15 no.4
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• pp.91-97
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• 2015

General companies consider saving the information after enciphering as law. However, if the actual information is saved as enciphered, the decoding process must be conducted when the information is searched or edited in the ser ver. Therefore, process delay time occurs and is less efficient. This kind of work gives burden to the server, so the companies or managers handling the server do not save the information after enciphering. In this paper, the Networ k constructs and realizes an efficient security data management system that ensures safety and haste in operating u sing the homomorphic encryption technology, which collects information and decides quickly, and enables editing the encryption without a decoding process. To ensure the security of the embodied system, the existing encryption algo rithm can be used. Search method to use the keyword search. Additionally, by using a trapdoor, the keyword is not expose and it is changed whenever it is searched, and the formation of the keyword does not get exposed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.6
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• pp.1045-1057
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• 2022

Recently, the National Institute of Standards and Technology (NIST) announced four cryptographic algorithms as a standard candidates of Post-Quantum Cryptography (PQC). In this paper, we show that private key can be exposed by a non-profiling-based power analysis attack such as Correlation Power Analysis (CPA) and Differential Deep Learning Analysis (DDLA) on CRYSTALS-KYBER algorithm, which is decided as a standard in the PKE/KEM field. As a result of experiments, it was successful in recovering the linear polynomial coefficient of the private key. Furthermore, the private key can be sufficiently recovered with a 13.0 Normalized Maximum Margin (NMM) value when Hamming Weight of intermediate values is used as a label in DDLA. In addition, these non-profiling attacks can be prevented by applying countermeasures that randomly divides the ciphertext during the decryption process and randomizes the starting point of the coefficient-wise multiplication operation.