• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.3
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• pp.51-59
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• 2009

The CRT-RSA cryptosystem is very vulnerable to fault insertion attacks in which an attacker can extract the secret prime factors p, q of modulus N by inserting an error during the computational operation on the cryptographic chip. In this paper, after implementing the CRT-RSA cryptosystem, we try to extract the secret key embedded in commercial microcontroller using optical injection tools such as laser beam or camera flash. As a result, we make sure that the commercial microcontroller is very vulnerable to fault insertion attacks using laser beam and camera flash, and can apply the prime factorization attack on CRT-RSA Cryptosystem.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.5
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• pp.27-33
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• 2011

At FDTC'05 and CISC-W'10, the authors showed that if they decrease the number of rounds of AES and Triple-DES by using the fault injections, it is possible to recover the secret key of the target algorithms, respectively. In this paper, we propose a key recovery attack on HMAC by using the main idea of these attacks. This attack is applicable to HMAC based on MD-family hash functions and can recover the secret key with the negligible computational complexity. Particularly, the attack result on HMAC-SHA-2 is the first known key recovery attack result on this algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.1
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• pp.76-89
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• 2013

In this paper, we propose a novel optical fault detection scheme for RSA hardware based on Montgomery exponentiation, which can effectively detect optical fault injection during the exponent calculation. To protect the RSA hardware from the optical fault injection attack, we implemented integrity check logic for memory and optical fault detection logic for Montgomery-based multiplier. The proposed scheme is considered to be safe from various type of attack and it can be implemented with no additional operation time and small area overhead which is less than 3%.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.135-140
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• 2010

The computation using Chinese Remainder Theorem in RSA cryptosystem is well suited in the digital signature or decryption processing due to its low computational load compared to the case of general RSA without CRT. Since the RSA-CRT algorithm is vulnerable to many fault insertion attacks, some countermeasures against them were proposed. Among several countermeasures, Yen et al. proposed two schemes based on fault propagation method. Unfortunately, a new vulnerability was founded in FDTC 2006 conference. To improve the original schemes, Kim et al. recently proposed a new countermeasure in which they adopt the AND operation for fault propagation. In this paper, we show that the proposed scheme using AND operation without checking procedure is also vulnerable to fault insertion attack with chosen messages.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.68-75
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• 2013

Recently, there has been introduced various types of pairing computations to implement ID based cryptosystem for mobile ad hoc network. According to spreading the applications of pairing computations, various fault attacks have been proposed. Among them, a counter fault attack has been considered the strongest threat. Thus this paper proposes a new countermeasure to prevent the counter fault attack on Miller's algorithm. The proposed method is able to reduce the possibility of fault propagation by a random index of intermediate values. Additionally, it is difficult to challenge fault attacks on the proposed method since a simple side channel leakage of 'if' branch is eliminated.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.5
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• pp.1071-1078
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• 2018

Recently, a family of lightweight block ciphers CHAM that has effective performance on resource-constrained devices is proposed. The CHAM uses a stateless-on-the-fly key schedule method which can reduce the key storage areas. Furthermore, the core design of CHAM is based on ARX(Addition, Rotation and XOR) operations which can enhance the computational performance. Nevertheless, we point out that the CHAM algorithm may be vulnerable to the fault injection attack which can reveal 4 round keys and derive the secret key from them. As a simulation result, the proposed fault injection attack can extract the secret key of CHAM-128/128 block cipher using about 24 correct-faulty cipher text pairs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.5
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• pp.859-865
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• 2013

Esmbedded devices such as smart cards and electronic passports highly demand security of sensitive data. So, the secure implementation of the cryptographic system against various side-channel attacks are becoming more important. In particular, the fault injection attack is one of the threats to the cryptosystem and can destroy the whole system only with single pair of the plain and cipher texts. Therefore, the implementors must consider seriously the attack. Several techniques for preventing fault injection attacks were introduced to a variety of the cryptosystem, But the countermeasures are still inefficient to be applied to the classical RSA cryptosystem. This paper introduces an efficient countermeasure against the fault injection attack for the classical RSA cryptosystem, which is based on the famous Fermat's theorem. The proposed countermeasure has the advantage that it has less computational overhead, compared with the previous countermeasures.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.4
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• pp.709-717
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• 2012

The round reduction on block cipher is a fault injection attack in which an attacker inserts temporary errors in cryptographic devices and extracts a secret key by reducing the number of operational round. In this paper, we proposed an improved round reduction method to retrieve master keys by injecting a fault during operation of loop statement in the Triple DES. Using laser fault injection experiment, we also verified that the proposed attack could be applied to a pure microprocessor ATmega 128 chip in which the Triple DES algorithm was implemented. Compared with previous attack method which is required 9 faulty-correct cipher text pairs and some exhaustive searches, the proposed one could extract three 56-bit secret keys with just 5 faulty cipher texts.

• ETRI Journal
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• v.33 no.3
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• pp.434-442
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• 2011

This paper presents a practical differential fault analysis method for the faulty Advanced Encryption Standard (AES) with a reduced round by means of a semi-invasive fault injection. To verify our proposal, we implement the AES software on the ATmega128 microcontroller as recommended in the standard document FIPS 197. We reduce the number of rounds using a laser beam injection in the experiment. To deduce the initial round key, we perform an exhaustive search for possible key bytes associated with faulty ciphertexts. Based on the simulation result, our proposal extracts the AES 128-bit secret key in less than 10 hours with 10 pairs of plaintext and faulty ciphertext.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.17-24
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• 2010

A differential fault attack(DFA) is one of the most efficient side channel attacks on block ciphers. Almost all block ciphers, such as DES, AES, ARIA, SEED and so on., have been analysed by this attack. In the case of the known DFAs on SEED, the attacker induces permanent faults on a whole left register of round 16. In this paper, we analyse SEED against DFA with differential characteristics and addition-XOR characteristics of the round function of SEED. The fault assumption of our attack is that the attacker induces 1-bit faults on a particular register. By using our attack, we can recover last round keys and the master key with about $2^{32}$ simple arithmetic operations. It can be simulated on general PC within about a couple of second.