• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.12C
• /
• pp.1193-1200
• /
• 2005

In this paper, we proposed an image hiding method which decreases the amount of calculation encrypting partial data rather than the whole image data using a discrete wavelet transform and a linear scalar quantization which have been adopted as the main technique in JPEG2000 standard and then implemented the proposed algorithm to hardware. A chaotic system was used instead of encryption algorithms to reduce further amount of calculation. It uses a method of random changing method using the chaotic system of the data in a selected subband. For ciphering the quantization index it uses a novel image encryption algorithm of cyclical shifting to the right or left direction and encrypts two quantization assignment method (Top-down coding and Reflection coding), made change of data less. The experiments have been performed with the proposed methods implemented in software for about 500 images. The hardware encryption system was synthesized to find the gate-level circuit with the Samsung $0.35{\mu}m$ Phantom-cell library and timing simulation was performed, which resulted in the stable operation in the frequency above 100MHz.

• Journal of Korea Multimedia Society
• /
• v.11 no.5
• /
• pp.588-596
• /
• 2008

For the patients' privacy, secure access control of medical images is essentially necessary. In this paper, two types of Region of Interest (ROI)-based selective encryption schemes are proposed, which concentrate on the security of crucial parts in medical images. The first scheme randomly inverts the most significant bits of ROI coefficients in several high frequency subbands in the transform domain, which only incurs little loss on compression efficiency. The second scheme employs a symmetric key encryption to encrypt selectively the ROI data in the final code-stream, which provides sufficient confidentiality. Both of two schemes are backward compatible so as to ensure a standard bitstream compliant decoder so the encrypted images can be reconstructed without any crash.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.16 no.4
• /
• pp.470-480
• /
• 2016

The reversal of a silicon chip to find out its security structure is common and possible at the present time. Thanks to reversing, it is possible to use a probing attack to obtain useful information such as personal information or a cryptographic key. For this reason, security-related blocks such as DES (Data Encryption Standard), AES (Advanced Encryption Standard), and RSA (Rivest Shamir Adleman) engines should be located in the lower layer of the chip to guard against a probing attack; in this regard, the addition of a silicon-surface-protection layer onto the chip surface is a crucial protective measure. But, for manufacturers, the implementation of an additional silicon layer is burdensome, because the addition of just one layer to a chip significantly increases the overall production cost; furthermore, the chip size is increased due to the bulk of the secure logic part and routing area of the silicon protection layer. To resolve this issue, this paper proposes a practical silicon-surface-protection method using a metal layer that increases the security level of the chip while minimizing its size and cost. The proposed method uses a shift register for the alternation and variation of the metal-layer data, and the inter-connection area is removed to minimize the size and cost of the chip in a more extensive manner than related methods.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.4
• /
• pp.2292-2309
• /
• 2017

Ciphertext policy attribute-based encryption (CP-ABE) is a useful cryptographic technology for guaranteeing data confidentiality but also fine-grained access control. Typically, CP-ABE can be divided into two classes: small universe with polynomial attribute space and large universe with unbounded attribute space. Since the learning with errors over rings (R-LWE) assumption has characteristics of simple algebraic structure and simple calculations, based on R-LWE, we propose a small universe CP-ABE scheme to improve the efficiency of the scheme proposed by Zhang et al. (AsiaCCS 2012). On this basis, to achieve unbounded attribute space and improve the expression of attribute, we propose a large universe CP-ABE scheme with the help of a full-rank differences function. In this scheme, all polynomials in the R-LWE can be used as values of an attribute, and these values do not need to be enumerated at the setup phase. Different trapdoors are used to generate secret keys in the key generation and the security proof. Both proposed schemes are selectively secure in the standard model under R-LWE. Comparison with other schemes demonstrates that our schemes are simpler and more efficient. R-LWE can obtain greater efficiency, and unbounded attribute space means more flexibility, so our research is suitable in practices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.359-362
• /
• 2014

With recent growing of application service, servers are required to sustain great amount of data and to handle them quickly: besides, data must be processed securely. The main security algorithm used in security services of server is AES(Advanced Encryption Standard - 2001 published by NIST), which is widely accepted in the world market for superiority of performance. In Korea, NSRI(National Security Research Institute) has developed ARIA(Academy, Research Institute, Agency) algorithm in 2004 and LEA(Lightweight Encryption Algorithm) algorithm in 2012. In this paper, we show advantage of LEA by comparing performance with AES and ARIA in various servers.

• The Journal of the Korea Contents Association
• /
• v.5 no.5
• /
• pp.43-50
• /
• 2005

POS system that become that is supply net administration and computerization fetters of customer management that become point in istribution network constructed database and use XML-Encryption that is certificate techniques of PKI and standard of security for security that is XML's shortcoming and design distributed processing POS system using XML for data integration by introduction of Ubiquitous concept. This POS system has four advantages. First, Because there is no server, need not to attempt authentication and data transmission every time. Second, can integrate data base by XML and improve portability of program itself. Third, XML data in data transmission because transmit data after encryption data safe .Fourth, After encode whenever process data for data breakup anger of POS system client program and elevation of the processing speed, transmit at because gathering data at data transmission.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.8
• /
• pp.1441-1447
• /
• 2008

It is possible to transfer huge data in mobile device by advancing mobile technology, and so in this base, various services are offered. Especially, E-commerce service is offering on mobile environment, and this service is based on XML(eXtensible Markup Language) Signature. XML Signature assure that process integrity, message authentication, and/or signer authentication. And WIPI(Wireless Internet Protocol for Interoperability) that is mobile internet integration platform was proposed to integrate mobile device platform. However, because WIPI transmits and exchanges message by tort of XML base, encryption of XML document and necessity of XML signature are increasing because of weakness of security. Therefor in this paper, Encryption and XML signature module of XML document that satisfy standard requirement in WIPI platform base design and implementation. System that was proposed in this paper used standard encryption and XML signature algorithm and supports safe encryption and XML signature through doing security simulation applied various algorithm for XML document of mobile environment.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.11
• /
• pp.2031-2038
• /
• 2008

A small-area and high-speed authentication/security processor (WUSB_Sec) IP is designed, which performs the 4-way handshake protocol for authentication between host and device, and data encryption/decryption of wireless USB system. The PRF-256 and PRF-64 are implemented by CCM (Counter mode with CBC-MAC) operation, and the CCM is designed with two AES (Advanced Encryption Standard) encryption coles working concurrently for parallel processing of CBC mode and CTR mode operations. The AES core that is an essential block of the WUSB_Sec processor is designed by applying composite field arithmetic on AF$(((2^2)^2)^2)$. Also, S-Box sharing between SubByte block and key scheduler block reduces the gate count by 10%. The designed WUSB_Sec processor has 25,000 gates and the estimated throughput rate is about 480Mbps at 120MHz clock frequency.

• Journal of the Korean Data and Information Science Society
• /
• v.18 no.1
• /
• pp.107-121
• /
• 2007

An efficient encoding algorithm (or encryption algorithm) is essential for mobile devices since their resources such as computation power and battery capacity are very limited. This study is to propose an efficient encoding scheme for protecting mobile music. In the proposed scheme, server distributes each music file in a shuffled form or an encrypted one, then only authorized consumers can play the music after un-shuffling or decrypting it. We show the effectiveness of our proposed scheme by implementing and evaluating the prototype system on WIPI emulator. Experimental results show that our scheme can achieve much better performance than the standard encryption algorithm of OMA DRM.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.41 no.4
• /
• pp.9-21
• /
• 2004

In this paper, we proposed the image hiding method which decreases calculation amount by encrypt partial data using discrete wavelet transform and linear scale quantization which were adopted as the main technique for frequency transform in JPEG2000 standard. Also we used the chaotic system which has smaller calculation amount than other encryption algorithms and then dramatically decreased calculation amount. This method operates encryption process between quantization and entropy coding for preserving compression ratio of images and uses the subband selection method and the random changing method using the chaotic system. For ciphering the quantization index we use a novel image encryption algerian of cyclically shifted in the right or left direction and encrypts two quantization assignment method (Top-down/Reflection code), made change of data less. Also, suggested encryption method to JPEG2000 progressive transmission. The experiments have been performed with the proposed methods implemented in software for about 500 images. consequently, we are sure that the proposed are efficient image encryption methods to acquire the high encryption effect with small amount of encryption. It has been shown that there exits a relation of trade-off between the execution time and the effect of the encryption. It means that the proposed methods can be selectively used according to the application areas. Also, because the proposed methods are performed in the application layer, they are expected to be a good solution for the end-to-end security problem, which is appearing as one of the important problems in the networks with both wired and wireless sections.