• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.888-894
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• 2015

This paper describes an efficient hardware design of Lightweight Encryption Algorithm (LEA) developed by National Security Research Institute(NSRI). The LEA crypto-processor supports for master key of 128-bit. To achieve small-area and low-power implementation, an efficient hardware sharing is employed, which shares hardware resources for encryption and decryption in round transformation block and key scheduler. The designed LEA crypto-processor was verified by FPGA implementation. The LEA core synthesized with Xilinx ISE has 1,498 slice elements, and the estimated throughput is 216.24 Mbps with 135.15 MHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.401-403
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• 2015

This paper describes an efficient hardware design of 128-bit block cipher algorithm LEA(lightweight encryption algorithm). In order to achieve area-efficient and low-power implementation, round block and key scheduler block are optimized to share hardware resources for encryption and decryption. The key scheduler register is modified to reduce clock cycles required for key scheduling, which results in improved encryption/decryption performance. FPGA synthesis results of the LEA processor show that it has 2,364 slices, and the estimated performance for the master key of 128/192/256-bit at 113 MHz clock frequency is about 181/162/109 Mbps, respectively.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.4
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• pp.107-112
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• 2000

In this paper, we study a security of HEA(Hangul Encryption Algorithm) against differential cryptanalysis. HEA, which is 1,024bits input/output and 56bits key size, has the same structure as DES(Data Encyption Standard) only for Korean characters to be produced in ciphertexts. An encryption algorithm should be developed to meet certain critria such as input/ouput dependencies, correlation, avalanche effects, etc. However HEA uses the same S-Boxes as DES does and just expands the plaintext/ciphertext sizes . We analysize HEA with a differential cryptanalysis and present two results. The number of rounds of HEA has not been determined in a concrete basis of cryptanalysis and we show a chosen plintext attack of 10 round reduced HEA with a diffe- rential cryptanalysis characteristic.

• International Journal of Computer Science & Network Security
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• v.21 no.12
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• pp.235-247
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• 2021

Today, the cloud computing has become a major demand of many organizations. The major reason behind this expansion is due to its cloud's sharing infrastructure with higher computing efficiency, lower cost and higher fle3xibility. But, still the security is being a hurdle that blocks the success of the cloud computing platform. Therefore, a novel Multi-tenant Decentralized Information Flow Control (MT-DIFC) model is introduced in this research work. The proposed system will encapsulate four types of entities: (1) The central authority (CA), (2) The encryption proxy (EP), (3) Cloud server CS and (4) Multi-tenant Cloud virtual machines. Our contribution resides within the encryption proxy (EP). Initially, the trust level of all the users within each of the cloud is computed using the proposed two-stage trust computational model, wherein the user is categorized bas primary and secondary users. The primary and secondary users vary based on the application and data owner's preference. Based on the computed trust level, the access privilege is provided to the cloud users. In EP, the cipher text information flow security strategy is implemented using the blowfish encryption model. For the data encryption as well as decryption, the key generation is the crucial as well as the challenging part. In this research work, a new optimal key generation is carried out within the blowfish encryption Algorithm. In the blowfish encryption Algorithm, both the data encryption as well as decryption is accomplishment using the newly proposed optimal key. The proposed optimal key has been selected using a new Self Improved Cat and Mouse Based Optimizer (SI-CMBO), which has been an advanced version of the standard Cat and Mouse Based Optimizer. The proposed model is validated in terms of encryption time, decryption time, KPA attacks as well.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.247-250
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• 2008

RC6 which has different algorithm of encryption and decryption has been implemented to have the same algorithm between encryption' and decryption though inserting symmetry layer using simple rotate and logical operation. That means the half of whole RC6 round uses encryption algorithm and the rest of it uses decryption one and symmetry layer has been put into the middle of encryption and decryption. The proposed RC6 algorithm has no difference with the original one in the speed of process. However it is quite safe because by inserting symmetry layer the path of high probability which is needed for differential and linear analysis is cut oft so that it is hard to be analyzed. The proposed algorithm can be easily applied to the algorithm which has different encryption and decryption an make it same, and it can be good idea to be used to design a new block cipher algorithm.

• The Journal of Information Technology
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• v.5 no.4
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• pp.115-127
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• 2002

This paper proposes improved file encryption algorithm which represents image of grayscale type not using proper cover image for ciphertext. This method consists of 3-Tire encryption steps. 1-Tire and 2-Tire encrypt the information using existed stream algorithm and block algorithm with modyfied padding method. We propose the MBE method as 3-Tire, which hides structure and format of encrypted file. The proposed method outputs grayscale file as the result of encryption and since many GSF outputs resulted from different kinds plaintexts, have similar patterns. we obtain both file encryption and hiding the file information. Also, to solve the problem of padding in block algorithm, we propose the new padding algorithm called SELI(Select Insert) and apply 2-Tire block algorithm and MBE algorithm used 3-Tire.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.700-702
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• 1999

The protection of data which we want to keep secret from invalid users has become a main topic nowadays. This paper introduces a encryption scheme for protecting speech signals from eavesdropping. The proposed encryption scheme adopts a secure voice cryptographic algorithm based on the scrambling in frequency band. In order to improve the conventional speech signal encryption scheme, we have randomly permuted DCT coefficients of speech signal. Simulation results are included to show the performance of the proposed algorithm for secure transmission of speech signals.

• Journal of information and communication convergence engineering
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• v.9 no.3
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• pp.271-275
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• 2011

In this paper, we present a hybrid encryption for a digital hologram which is the most valuable image content. The encryption algorithm is based on a hybrid technique implementation a four-dimensional transform combining the discrete wavelet transform(DWT) and the discrete cosine transform (DCT). The encryption scheme is composed on the basis of the energy distribution. The experimental results showed that encrypting only 0.0244% of the entire data was enough to hide the constants of the hologram. The encryption algorithm expected to be used effectively on the researches on encryption and others for digital holographic display.

• Current Optics and Photonics
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• v.5 no.2
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• pp.155-163
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• 2021

We propose a novel optical encryption scheme for cipher-feedback-block (CFB) mode, capable of encrypting two-dimensional (2D) page data with the use of two-step phase-shifting digital interferometry utilizing orthogonal polarization, in which the CFB algorithm is modified into an optical method to enhance security. The encryption is performed in the Fourier domain to record interferograms on charge-coupled devices (CCD)s with 256 quantized gray levels. A page of plaintext is encrypted into digital interferograms of ciphertexts, which are transmitted over a digital information network and then can be decrypted by digital computation according to the given CFB algorithm. The encryption key used in the decryption procedure and the plaintext are reconstructed by dual phase-shifting interferometry, providing high security in the cryptosystem. Also, each plaintext is sequentially encrypted using different encryption keys. The random-phase mask attached to the plaintext provides resistance against possible attacks. The feasibility and reliability of the proposed CFB method are verified and analyzed with numerical simulations.

• The Journal of Society for e-Business Studies
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• v.5 no.1
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• pp.55-73
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• 2000

Recently; EC(Electronic Commerce) is increasing with high speed based on the expansion of Internet. EC which is done on the cyber space through Internet has strong point like independence from time and space. On the contrary, it also has weak point like security problem because anybody can access easily to the system due to open network attribute of Internet. Therefore, we need the solutions that protect the security problem for safe and useful EC activity. One of these solutions is the implementation of strong cipher algorithm. NC(Nonpolynomial Complete) cipher algorithm proposed in this paper is good for the security and it overcome the limit of current 64bits cipher algorithm using 128bits key length for input, output and encryption key, Moreover, it is designed for the increase of calculation complexity and probability calculation by adapting more complex design for subkey generation regarded as one of important element effected to encryption. The result of simulation by the comparison with other cipher algorithm for capacity evaluation of proposed NC cipher algorithm is that the speed of encryption and decryption is 7.63 Mbps per block and the speed of subkey generation is 2,42 μ sec per block. So, prosed NC cipher algorithm is regarded as proper level for encryption. Furthermore, speed of subkey generation shows that NC cipher algorithm has the probability used to MAC(Message Authentication Code) and block implementation of Hash function.