ChangKyun Kim

A Secure and Practical CRT-Based RSA to Resist Side Channel Attacks

A secure and practical CRT-based RSA signature scheme is proposed against side channel attacks, including power analysis attack, timing attack, and fault analysis attack. The performance advantage obtained over other existing countermeasures is demonstrated. To prevent from fault attack, the proposed countermeasure employs a fault diffusion concept which is to spread the fault into the correct term during the recombination process by using CRT. This new countermeasure is also secure against differential power attack by using the message random blinding technique on RSA with CRT.

A CRT-based RSA countermeasure against physical cryptanalysis

This paper considers a secure and practical CRT-based RSA signature implementation against both side channel attacks (including power analysis attack, timing attack, and most specially the recent MRED attack) as well as the various CRT-based fault attacks. Moreover, the proposed countermeasure can resist C safe-error attack which can be mounted in many existing good countermeasures. To resist side-channel attack, a special design of random message blinding is employed. On the other hand, a countermeasure based on the idea of fault diffusion is developed to protect the implementation against the powerful CRT-based fault attacks.

Differential power analysis on block cipher ARIA

ARIA is a 128-bit symmetric block cipher having 128-bit, 192-bit, or 256-bit key lengths. The cipher is a substitution-permutation encryption network (SPN) that uses an involutional binary matrix. This paper shows that a careless implementation of ARIA on smartcards is vulnerable to a differential power analysis attack. This attack is realistic because we can measure power consumption signals at two kinds of S-boxes and two types of substitution layers. By analyzing the power traces, we can find all round keys and also extract a master key from only two round keys using circular rotation, XOR, and involutional operations for two types of layers.

Side channel cryptanalysis on SEED

The Korea standard block cipher, SEED, is a 128-bit symmetric block cipher with a more complex F function than DES. This paper shows that SEED is vulnerable to two types of side channel attacks, a fault analysis attack and a power analysis attack. The first one is a fault insertion analysis which induces permanent faults on the whole left register of 15-round. This attack allows one to obtain the secret key by using only two faulty cipher texts for encryption and decryption processing respectively. The second attack is a more realistic differential power analysis. This attack requires about 1000 power traces to find the full secret key. The above two attacks use a reverse property of the F function to obtain secret key, where the reverse property is derived from the our research.

The Study on Fault Injection Attack: The analysis and improvement of the experimental precision indicators*

ABSTRACT As the utilization rate of smart device increases, various applications for smart device have been developed. Since these applications can contain important data related to user behavio rs in digital forensic perspective, the analysis of them should be conducted in advance. However, lots of applications get to have new data format or type when they are updated. Therefore, whether the applications are updated or not should be checked o ne by one, and if they are, whether their data are changed should be also analyzed. But observing application data repeatedly is a time-consuming task, and that is why the effective method for dealing with this problem is needed. This paper suggests the automatic system which gets updated inf ormation and checks changed data by collecting application information. Keywords: Digital Forensics, Smartphone Forensics, Android Forensics, An droid Application, Android Data Acquisition접수일(2013년 12월 31일), 수정일(2014년 3월 4일), 게재확정일(2014년 3월 4일)* 본 연구는 2013년도 정부(교육과학기술부)의 재원으로 한국연구재단의 기초연구사업 지원을 받아 수행된 것임(과제번호: 2013-071188). 또한 부산광역시에서 지원하는 BB21과제에서 지원받았음.† 주저자, feei_@naver.com