Earticle

본 논문에서는 유비쿼터스 컴퓨팅 보안을 위한 128비트 Reversible Cellular Automata(RCA)기반 경량 블록 암호를 설계하고 구현한다. 유비쿼터스 컴퓨팅이 요구하는 하드웨어 제약조건을 충족하기 위하여 높은 임의성을 제공하는 Cellular Automata를 기반으로 블록구조를 설계하였다. 구현된 블록 암호기법은 암호화 과정동안 704 클럭 사이클로 동작하고 2,874 게이트수를 보였다. 구현 결과 기존의 AES나 NTRU보다 처리속도가 31% 향상되었고, gate수는 20%만큼 절감되었다. 차분 분석(Differential Cryptanalysis)과 Strict Avalanche Criterion(SAC)을 수행함으로써 구현된 블록 암호 알고리즘의 안정성을 검증하였다.

This paper presents a 128-bit Reversible Cellular Automata (RCA) based lightweight block cipher for Ubiquitous computing security. To satisfy resource-constraints for Ubiquitous computing, it is designed as block architecture based on Cellular Automata with high pseudo-randomness. Our implementation requires 704 clock cycles and consumes 2,874 gates for encryption of a 128-bit data block. In conclusion, the processing time outperformed that of AES and NTRU by 31%, and the number of gate was saved by 20%. We evaluate robustness of our implementation against both Differential Cryptanalysis and Strict Avalanche Criterion.

무선 인터넷과 IoT(Internet of Things) 기술 기반의 다양한 스마트기기가 확산함에 따라 경량 블록 암호 기술의 사용이 증가하고 있다. 경량 블록 암호는 저전력과 저면적 환경에서 데이터의 보안, 무결성, 인증 등 스마트 기기의 정보보호에 필수적인 기술로 자리 잡고 있다. 그러나, 개발된 경량 블록 암호 기술에 대한 공격 기법들이 연구되면서, 개선의 필요성이 대두되고 있다. 본 연구에서는 경량 블록 암호 기술을 개선하기 위해, 추가적인 논리 게이트오버헤드가 전혀 없는 비용 제로(zero-cost) 기반의 통계적 경로 재설계 기법(Statistical Path Redesign)을 제안한다. 이 통계적 경로 재설계 기법을 활용하여, 경량 블록 암호의 국제 표준으로 선정된 SPN(Substitution-Permutation Network) 구조의 PRESENT[2]와 ARX(Addition-Rotation-XOR) 구조의 HIGHT[3] 암호 기술에 대한 취약성을 분석하고, 최적화된 개선 방안을 제안한다. 그리고, 개선된 경량 블록 암호에 대해 기존 공격 기법들에 대한 저항성과 최초 제안된 경량 블록 암호와의 성능을 대수적 검증과 시뮬레이션 결과로 분석한다.

As various smart devices based on wireless internet and IoT(Internet of Things) technologies proliferate, the demand for lightweight block cipher technology continues to rise. Lightweight block ciphers have become an essential component for ensuring data security, integrity, and authentication in smart devices operating within low-power and resource-constrained environments. However, as cryptanalysis techniques against existing lightweight block ciphers advance, the necessity for structural improvement is emerging. In this paper, to enhance lightweight block cipher security, we propose a Statistical Path Redesign(SPR) technique achieved at zero-cost, incurring absolutely no additional logic gate overhead. Using this SPR technique, we analyze the vulnerabilities of the SPN(Substitution-Permutation Network)-based PRESENT[2] and ARX(Addition-Rotation-XOR)-based HIGHT[3] architectures which are both registered as international standards for lightweight ciphers, and propose optimized improvement schemes. Finally, through rigorous algebraic verification and extensive simulation results, we demonstrate that the enhanced lightweight block ciphers fundamentally evade known attack vectors while maintaining the performance profiles of the originally proposed designs.

초경량 LEA 128비트 블록 암호화 아키텍처는 자원이 제약된 유비쿼터스 장치에 보안성을 높일 방법으 로, 국가보안기술연구소에서 개발되고 국제표준화기구와 국제전기기술위원회에서 암호 분야 국제 표준으로 제정된 보안 알고리즘인 128비트 Lightweight Encryption Algorithm 알고리즘을 하드웨어 환경에서 설계하여 내부 레지 스터 재사용, 리소스 공유를 통해 LEA 암호화/복호화 모듈을 저 면적으로 구현하였다. Xilinx ISE 14.7 Virtex-5 를 이용하여 합성한 결과, 최대 주파수는 190.88MHz를 달성했으며 최대 128Mbps의 처리 속도를 가진다. 또한, 301개의 Flip-Flop, 1151개의 Look-Up-Table, 485개의 슬라이스로 구현되어 128비트 LEA 알고리즘을 저면적으 로 구현된 하드웨어 디자인을 제시한다.

In this paper, we present an efficient hardware design of the 128-bit Lightweight Encryption Algorithm. LEA is a security algorithm developed by the National Security Technology Institute and established as an international standard for cryptography in the International Organization for Standardization and International Electrotechnical Commission for use in a hardware environment. The proposed architecture is based on internal register reuse and resource sharing to lower the LEA encryption/decryption crypto core’s area. The maximum frequency is 190.88MHz and has throughput of 128Mbps. In addition, 301 Flip-Flops, 1151 Look-Up-Tables, and 485 Slices are utilized to present a low-area 128-bit LEA hardware design.

WEP은 향후 네트워크 시장을 주도할 무선 랜에서 암호화 기능과 인증 기능을 제공하기 위하여 제시된 보안 프로토콜이다. 그러나 WEP는 암호문 생성 시 사용되는 초기 값 생성에 대한 구체적인 방법이 제시하고 있지 않으며, 초기 값의 크기 및 재사용 문제로 인하여 암호화를 하는 경우 안전성에 대한 문제가 제기되고 있다. 본 논문에서는 WEP의 취약점들을 지적하고 이에 대한 개선안을 제시하였고 제시한 개선안을 토대로 초기 값 재사용을 방지할 수 있는 초기 값 생성 시스템과 블록 암호 CBC 모드를 이용하여 기밀성과 상호 인증 기능을 제공할 수 있는 새로운 무선랜 보안 모델을 제안하였다.

WEP is proposed networks dominate the market in the future wireless LAN encryption and authentication features to provide a secure protocol. However, WEP does not suggest a specific measures when generating the initial values ??used for the creation cipher text, the initial value problem because the size and re-encryption if you have been raised about the safety issue. In this paper pointed out the vulnerabilities of WEP and the proposed improvement plan for this improvement was proposed based on the initial value to avoid re-creating the initial value of the system and using a block cipher in CBC mode for confidentiality and to provide mutual authentication New WLAN security model was proposed.

최근 차세대 전자상거래 및 금융 분야에서는 비트코인, 이더리움 등의 블록체인 기반 기술에 관심이 크다. 블록체인 기술의 보안성은 안전하다고 알려졌지만, 가상화폐 관련 해킹 사건/사고들이 이슈화되고 있다. 가상화폐 지갑에 대한 로그 인 세션 탈취, 악성코드 감염으로 인한 개인키 노출, 단순한 암호 사용 등 외부환경의 취약성이 주요 원인이었다. 그러나 개인키 관리는 전용 애플리케이션 활용 또는 로컬 백업, 문서 프린트를 통한 물리적 보관 등 일반적인 방법을 권장하고 있다. 본 연구에서는 화이트박스 암호 기반 개인키 보호 기법을 제안한다. 안전성 및 성능분석 결과 개인키 노출 취약점에 대한 안전성을 강화하고, 암호화키를 알고리즘에 내장하여 기존 프로토콜의 처리 효율성을 증명하였다.

Recently, in the field of next-generation e-commerce and finance, interest in blockchain-based technologies such as Bitcoin and Ethereum is great. Although the security of blockchain technology is known to be secure, hacking incidents / accidents related to cryptocurrencies are being issued. The main causes were vulnerabilities in the external environment, such as taking over login sessions on cryptocurrency wallets, exposing private keys due to malware infection, and using simple passwords. However, private key management recommends general methods such as utilizing a dedicated application or local backup and physical archiving through document printing. In this paper, we propose a white box password-based private key protection scheme. As a result of safety and performance analysis, we strengthened the security against vulnerability of private key exposure and proved the processing efficiency of existing protocol.

This paper presents the implementation of high-speed block, cipher, HIGHT. The proposed architecture employs parallel architecture to enhance throughput. In addition, it shares key scheduling block for encryption and decryption to reduce hardware complexity. It also introduces an efficient protocol applicable to RFID systems, implementing the HIGHT block cipher algorithm. The new HIGHT structure yields a size small enough to afford tag applications and twice as high performance with respect to conventional HIGHT implementation. The proposed protocol overcomes the security vulnerability of RFID tags, and reduces energy consumption per transaction by sharing key generation.

Wireless sensor network (WSN) is a collection of densely deployed sensor nodes. These nodes are prone to attack and also resource constrained. Resource accountability is also required for Security implementation in WSN. Some researchers proposed different methods, algorithms and frameworks for WSN security implementation. SPINS is a framework for implementing overall security in WSN using SNEP (Sensor Network Encryption Protocol) and μTESLA (the “micro” version of the Timed, Efficient, Streaming, Loss-tolerant Authentication Protocol) protocol. Existing research works reveal that SNEP employed RC5 encryption algorithm for WSN. This paper analyzed efficient encryption algorithm XTEA for SNEP & evaluate that it is better as compare to RC5 in terms of energy, storage and time.

How to protect the secret digital images is an important issue in commercial or military application. In this paper, we propose a new scheme for secure still visual data with a block cipher structure, which is composed of three parts: encryption, decryption and key generator. The encryption process based on cryptographic primitive operations and Boolean functions is proposed. A key generator based on one-way coupled map lattice (OCML) is derived. Experimental results have demonstrated that the proposed cipher has satisfactory security with a low cost, which makes it a potential candidate for encryption of multimedia data such as images, audios and even videos.

This paper proposes three one-time password (OTP) generation methods suitable for firmware OTPs, one of the most representative methods for addressing the rapidly growing demand for user authentication in online services, based on stream and block ciphers. The first method is a stream cipher-based approach consisting of a 127-bit linear feedback shift register (LFSR) and exclusive-OR (XOR) operators. The OTP output bits are determined using a bit-position selection derived from the digits of  . The second method is a block cipherbased approach employing triple data encryption standard (TDES). Part of the output bits are used as the OTP output and the remaining bits are fed back to the input through an output feedback (OFB) mode. The third method adopts advanced encryption standard (AES) as the block cipher, using a portion of the output bits as the OTP output and feeding back a subset of the remaining bits to the input. All methods generate initial values through key-based random number generation applying message authentication code (MAC). The proposed methods are implemented on an Arduino platform as firmware-based OTP generators. Experimental results demonstrate that the proposed methods offer strong security properties and are suitable for firmwarebased OTP generation. In addition, the LFSR-based method shows good performance in the NIST SP 800-22 randomness tests.

Wireless Sensor Networks have been a great effect in our real life. With its various types of applications WSN is also a matter of concern for its existing vulnerabilities. To prevent those loopholes we need to provide some effective mechanism for providing better security and authentication issues. Wireless Sensor Networks also have a constraint of resources as the nodes work on battery power. In our paper, we have shown such an effective mechanism using a combination of DES and Blowfish in CBC mode for security enhancement which provides high data confidentiality and authentication.

In this paper, we propose the 16-bits optimization design of the ARIA block-cipher algorithm for embedded systems with 16-bits processors. The proposed design adopts 16-bits XOR operations and rotated shift operations as many as possible. Also, the proposed design extends 8-bits array variables into 16-bits array variables for faster chained matrix multiplication. In evaluation experiments, our design is compared to the previous 32-bits optimized design and 8-bits optimized design. Our 16-bits optimized design yields about 20% faster execution speed and about 28% smaller footprint than 32-bits optimized code. Also, our design yields about 91% faster execution speed with larger footprint than 8-bits optimized code.

The Block cipher BM–128 which is proved to be suitable to the applications in the wireless communication systems are proposed in this paper. It is developed based on SDDO which is constructed from CSPN. BM-128 also eliminates the weak keys without the complex round key proceduce and meet the requirements of NESSIE. Design shall meet all the security requirements to protect applications against the well-known threats. In addition, BM-128 evaluated to have higher performance than the other algorithms when they are used in cheap hardware.

In this paper, we made a comprehensive simulative study on the performance assessment of a MIMO MC CDMA wireless communication system. The proposed system under investigation consider a communication link between three multi antenna supported units such as a mobile user unit, base station and relaying node. The system incorporates four low-complexity channel equalization techniques, various digital modulations and Block cipher encryption based channel coding schemes. From MATLAB based simulated study on synthetic data transmission, it is found a quite noticeable impact on deploying a single relaying node on performance enhancement of the presently considered MIMO MCCDMA system. The system is also capable of showing its robustness in retrieving transmitted data over hostile multipath fading channels in a scenario of thickly populated urban area.

SMS4 is a 128-bit block cipher with a 128-bit user key and 32 rounds, which is used in WAPI, the Chinese WLAN (Wireless Local Area Networks) national standard. The SMS4 cipher is suitable for pro- tections of pervasive computing systems especially where they require fast software implementations. This is due to the fact that SMS4 only uses simple operations like XORs and bitwise rotations, and look-up tables which are all very fast in software. In this paper, we present a boomerang attack on a 18-round reduced SMS4. The methods presented to attack SMS4 can be applied to other unbalanced Feistel ciphers with incomplete diffusion.

R. Chung-Wei Phan has presented a complementation slide attack on full Skipjack block cipher [1]. He claimed that the full 32 rounds of Skipjack was broken by a complementation slide attack with 2^32.5 known texts and 2^44 encryptions. In this paper, we show that his cryptanalysis method can not offer any information of subkeys in Skipjack.

This paper presents a technique for secret communication using cryptography and steganography. The cryptographic algorithm is a block cipher with a block length of 128 bits and key length of 256 bits. The secret message is encrypted by this block cipher. Two cipher text bits are to be embedded in each pixel of the image. Each pixel is 8 bits. The embedding locations in a pixel are: 6th and 7th bit locations or 7th and 6th bit locations or 7th and 8th bit locations or 8th and 7th bit locations depending upon the cipher text bits. The 8th bit means the least significant bit (LSB). As the embedding locations are decided at the run time of the algorithm, so it is called as dynamic steganography. The technique is experimented and results are discussed.

This paper presents a technique for secret communication using cryptography and steganography. The cryptographic algorithm is a block cipher with a block length of 128 bits and key length of 256 bits. The secret message is encrypted by this block cipher. Two cipher text bits are to be embedded in each pixel of the image. Each pixel is 8 bits. The embedding locations in a pixel are: 6th and 7th bit locations or 7th and 6th bit locations or 7th and 8th bit locations or 8th and 7th bit locations depending upon the cipher text bits. The 8th bit means the least significant bit (LSB). As the embedding locations are decided at the run time of the algorithm, so it is called as dynamic steganography. The technique is experimented and results are discussed.

블록 암호 알고리즘의 안전성을 평가하는 중요한 도구로 차분 공격과 선형 공격이 있다. 따라서 안전한 블록 암호를 설계하기 위해서는 차분 공격과 선형 공격에 대한 안전성을 평가해야 한다. 본 논문에서는 새로운 블록 암호 구조를 소개하며, 한 라운드 함수의 최대 차분 확률(최대 선형 확률)이 이고 라운드 함수가 전단사 함수일 때, 3 라운드 블록 암호 구조의 차분 확률(선형 확률)의 상한 값이 으로 유계함을 증명한다.

Differential cryptanalysis and linear cryptanalysis are the most powerful known attacks on block ciphers, and thus in order to design secure block ciphers they should be resistant to these attacks. In this paper, we present a new block cipher structure and we prove that differential (linear) probabilities for a 3-round block cipher structure are upper bounded by if the maximum differential (linear) probability of the round function is and the round function is a bijective function.

Serpent는 1998년부터 2000년까지 미국의 NIST에 의해 수행된 AES 공모 사업에서 최종 다섯 후보에 선정되었었던 블록 암호 알고리즘이다. 본 논문에서는 Serpent에 대하여 존재하는 선형근사식들을 지적하고, 이 근사식들을 이용하여 Serpent의 10, 11 라운드가 공격될 수 있음을 보인다. 4096개의 9 라운드 선형근사식들을 이용하면, 본 논문에서 소개되는 공격 알고리즘은 10 라운드 Serpent 서브키의 48비트를 추출할 수 있으며, 11 라운드 Serpent 서브키의 176비트를 추출할 수 있다. 10 라운드에 대한 공격에는 개의 평문과 , 11 라운드에 대한 공격에는 개의 평문이 소요된다. 11 라운드에 대한 공격은 시간복잡도가 높기 떄문에 256비트키에 대해서만 유효하다. 두 공격의 성공확률은 모두 90%이며, 이것은 평문의 양에 따라 조절될 수 있다.

Serpent is a block cipher which was selected as one of five AES finalists at AES project performed by NIST. In this paper, we indicate linear approximations in Serpent and attack 10 and 11 rounds of Serpent. Using 4096 linear approximations, our attack algorithm recover 48 subkey bits of 10-round Serpent (with plaintexts) and 176 subkey bits of 11-round Serpent (with plaintexts). The later attack is valid only for 256-bit master keys due to high time complexity. The success rate of both attacks is 90%, which is dependent on the number of plaintexts.