• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.33 no.3
• /
• pp.363-374
• /
• 2023

A white-box environment refers to a situation where the internal information of an algorithm is disclosed. The AES white-box encryption was first announced in 2002, and in 2016, a side-channel analysis for white-box encryption called Differential Computation Analysis (DCA) was proposed. DCA analysis is a powerful side-channel attack technique that uses the memory information of white-box encryption as side-channel information to find the key. Although various countermeasure studies against DCA have been published domestically and internationally, there were no evaluated or analyzed results from experiments applying the hiding technique using dummy operations to DCA analysis. Therefore, in this paper, we insert LU T-shaped dummy operations into the WBC-AES algorithm proposed by S. Chow in 2002 and quantitatively evaluate the degree of change in DCA analysis response depending on the size of the dummy. Compared to the DCA analysis proposed in 2016, which recovers a total of 16 bytes of the key, the countermeasure proposed in this paper was unable to recover up to 11 bytes of the key as the size of the dummy decreased, resulting in a maximum decrease in attack performance of about 68.8%, which is about 31.2% lower than the existing attack performance. The countermeasure proposed in this paper confirms that the attack performance significantly decreases as smaller dummy sizes are inserted and can be applied in various fields.

• Proceedings of the Korean Information Science Society Conference
• /
• 2012.06d
• /
• pp.308-310
• /
• 2012

최근 무선 센서 네트워크 환경에서 대용량 멀티미디어 데이터에 대한 요구가 증가하면서 통신 대역폭 및 한정적인 에너지의 한계를 극복하기 위한 대안으로 데이터 분할 및 다중 경로 기법들이 제안되었다. 기존 기법들은 데이터 전송 시에 발생하는 부하의 분산을 통해 네트워크의 성능을 향상시킬 수 있다는 것을 증명하였지만, 데이터의 효율적인 분할과 악의적인 공격에 의한 보안성 문제에 대해서 고려하지 않았다. 이러한 문제점을 해결하기 위해 본 논문에서는 비트평면 분할 기반의 보안성 있는 비-중첩 다중경로 라우팅 기법을 제안한다. 제안하는 기법은 멀티미디어 데이터를 비트평면 단위로 분할하여 다중 경로로 전송함으로써 기존의 키 기반의 암호화 기법을 사용하지 않고도 전체 네트워크에 대한 보안성을 향상 시켰다. 또한 경로 상 노드들의 잔여 에너지를 고려하여 데이터 전송을 수행함으로써 전체 네트워크의 에너지 효율성을 향상시켰다. 성능평가 결과, 제안하는 기법은 기존 기법에 비해 노드의 생존율이 평균 50% 이상 향상되었고, 데이터가 노출되더라도 해당 패킷을 가지고 본래 이미지를 복구하는 것이 불가능하기 때문에 높은 보안성을 제공한다.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.13 no.6
• /
• pp.141-148
• /
• 2003

The self-healing key distribution scheme with revocation capability proposed by Staddon et al. enables a dynamic group of users to establish a group key over an unreliable network, and has the ability to revoke users from and add users to the group while being resistant to collusion attacks. In such a protocol, if some packet gets lost, users ale still capable of recovering the group key using the received packets without requesting additional transmission from the group manager. In this scheme, the storage overhead at each group member is O($m^2$1og p) and the broadcast message size of a group manager is O( ((m$t^2$+mt)log p), where m is the number of sessions, t is the maximum number of colluding group members, and p is a prime number that is large enough to accommodate a cryptographic key. In this paper we describe the more efficient self-healing key distribution scheme with revocation capability, which achieves the same goal with O(mlog p) storage overhead and O(($t^2$+mt)log p) communication overhead. We can reduce storage overhead at each group member and the broadcast message size of the group manager without adding additional computations at user's end and group manager's end.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.29 no.5
• /
• pp.997-1006
• /
• 2019

To overcome the difficulties and inefficiencies of the existing power analysis attack, we try to extract the secret key embedded in a cryptographic device using attack model based on MLP(Multi-Layer Perceptron) method. The target of our proposed power analysis attack is the AES-128 encryption module implemented on an 8-bit processor XMEGA128. We use the divide-and-conquer method in bytes to recover the whole 16 bytes secret key. As a result, the MLP-based power analysis attack can extract the secret key with the accuracy of 89.51%. Additionally, this MLP model has the 94.51% accuracy when the pre-processing method on power traces is applied. Compared to the machine leaning-based model SVM(Support Vector Machine), we show that the MLP can be a outstanding method in power analysis attacks due to excellent ability for feature extraction.

• Journal of Internet of Things and Convergence
• /
• v.6 no.2
• /
• pp.93-100
• /
• 2020

Although various home services are developed as increasing the number of home devices with wire and wireless connection, privacy infringement and private information leakage are occurred by unauthorized remote connection. It is almost caused by without of device authentication and protection of transmission data. In this paper, the devices' secret value are stored in a safe memory of a smartphone. A smartphone processes device authentication. In order to prevent leakage of a device's password, a shadow password multiplied a password by the private key is stored in a device. It is proposed mutual authentication between a smartphone and a device, and session key agreement for devices using recovered passwords on SRP. The proposed protocol is resistant to eavesdropping, a reply attack, impersonation attack.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.24 no.6
• /
• pp.1117-1127
• /
• 2014

Differential Fault Analysis(DFA) is widely known for one of the most powerful method for analyzing block cipher. it is applicable to block cipher such as DES, AES, ARIA, SEED, and lightweight block cipher such as PRESENT, HIGHT. In this paper, we introduce a differential fault analysis on the lightweight block cipher LEA for the first time. we use 300 chosen fault injection ciphertexts to recover 128-bit master key. As a result of our attack, we found a full master key within an average of 40 minutes on a standard PC environment.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.19 no.5
• /
• pp.167-174
• /
• 2009

Recently, Li et al. proposed a new differential fault analysis(DFA) attack on the block cipher ARIA using about 45 ciphertexts. In this paper, we apply their DFA skill on AES and improve attack method and its analysis. The basic idea of our DFA method is that we recover intermediate ciphertexts in last round using final faulty ciphertexts and find out last round secret key. In addition, we present detail DFA procedure on AES and analysis of complexity. Furthermore computer simulation result shows that we can recover its 128-bit secret key by introducing a correct ciphertext and 2 faulty ciphertexts.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.27 no.4
• /
• pp.923-941
• /
• 2017

A side-channel attack is a method of attacking a cipher based on physical information of a cryptographic device. The masking method, which is a typical method overcoming this attack, is a method of calculating an arbitrary masking value at the round intermediate value through rounds. Thus, it is difficult to guess the intermediate value by the side-channel attack, but if the masking operation is applied to all rounds of the encryption algorithm, the encryption process may become overloaded. Therefore, it is practical to use a reduced-round masking technique that applies a masking technique to only a part of the cipher for lightweight equipment such as Internet of Things(IoT) and wearable devices. In this paper, we describe a Hamming weight filtering for SIMON family with reduced-round masking technique and it is shown that first round key recovery is possible through actual programming.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.25 no.2
• /
• pp.253-260
• /
• 2015

The side-channel attack is widely known as an attack on implementations of cryptographic algorithms using additional side-channel information such as power traces, electromagnetic waves and sounds. As a countermeasure of side channel attack, the masking method is usually used, however full-round masking makes the efficiency of ciphers dramatically decreased. In order to avoid such a loss of efficiency, one can use reduced-round masking. In this paper, we describe a side channel attack on the lightweight block cipher LEA with the first one~six rounds masked. Our attack is based on differentials and power traces which provide knowledge of Hamming weight for the intermediate data computed during the enciphering of plaintexts. According to our experimental result, it is possible to recover 25 bits of the first round key in LEA-128.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.21 no.6
• /
• pp.35-44
• /
• 2011

The PP-1/64-128 block cipher support variety data block and secret key size. Also, it is suitable for hardware implementation and can much easier to apply Concurrent Error Detection(CED) for cryptographic chips compared to other block ciphers, because it has same encryption and decryption process. In this paper, we proposed truncated differential cryptanalysis of PP-1/64-128. the attack on PP-1/64-128 block cipher requires $2^{50.16}$ chosen plaintexts, $2^{46.16}$ bytes memory spaces and $2^{50.45}$ PP-1/64-128 encryption to retrieve secret key. This is the best result of currently known PP-1/64-128 differential cryptanalysis.