• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1329-1342
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• 2018

Recent advances in quantum computer development have raised the issue of the security of RSA and elliptic curve cryptography, which are widely used. In response, the National Institute of Standards and Technology(NIST) is working on the standardization of public key cryptosystem which is secure in the quantum computing environment. Lattice-based cryptography is a typical post-quantum cryptography(PQC), and various lattice-based cryptographic schemes have been proposed for NIST's PQC standardization contest. Among them, EMBLEM proposed a new multi-bit encryption method which is more intuitive and efficient for encryption and decryption phases than the existing LWE-based encryption schemes. In this paper, we propose a multi-bit encryption scheme with improved efficiency using LWR assumption. In addition, we prove the security of our schemes and analyze the efficiency by comparing with EMBLEM and R.EMBLEM.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.12
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• pp.453-460
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• 2022

As high-performance quantum computers are expected to be developed, studies are being actively conducted to build a post-quantum security system that is safe from potential quantum computer attacks. When the Grover's algorithm, a representative quantum algorithm, is used to search for a secret key in a symmetric key cryptography, there may be a safety problem in that the security strength of the cipher is reduced to the square root. NIST presents the post-quantum security strength estimated based on the cost of the Grover's algorithm required for an attack of the cryptographic algorithm as a post-quantum security requirement for symmetric key cryptography. The estimated cost of Grover's algorithm for the attack of symmetric key cryptography is determined by the quantum circuit complexity of the corresponding encryption algorithm. In this paper, the quantum circuit of the SCHWAEMM algorithm, AEAD family of SPARKLE, which was a finalist in NIST's lightweight cryptography competition, is efficiently implemented, and the quantum cost to apply the Grover's algorithm is analyzed. At this time, the cost according to the CDKM ripple-carry adder and the unbounded Fan-Out adder is compared together. Finally, we evaluate the post-quantum security strength of the lightweight cryptography SPARKLE SCHWAEMM algorithm based on the analyzed cost and NIST's post-quantum security requirements. A quantum programming tool, ProjectQ, is used to implement the quantum circuit and analyze its cost.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.6
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• pp.1149-1156
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• 2021

The Grover algorithm, which accelerates the brute force attack, is applicable to key recovery of symmetric key cryptography, and NIST uses the Grover attack cost for symmetric key cryptography to estimate the post-quantum security strength. In this paper, we estimate the attack cost of Grover's algorithm by implementing DES as a quantum circuit. NIST estimates the post-quantum security strength based on the attack cost of AES for symmetric key cryptography using 128, 192, and 256-bit keys. The estimated attack cost for DES can be analyzed to see how resistant DES is to attacks from quantum computers. Currently, since there is no post-quantum security index for symmetric key ciphers using 64-bit keys, the Grover attack cost for DES using 64-bit keys estimated in this paper can be used as a standard. ProjectQ, a quantum programming tool, was used to analyze the suitability and attack cost of the quantum circuit implementation of the proposed DES.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.3
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• pp.473-480
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• 2021

To achieve the high-speed implementation of post-quantum cryptography, primitive operations should be tailored to the architecture of the target processor. In this paper, we present the optimized implementation of multiplier operation on RISC-V processor for post-quantum cryptography. Particularly, the column-wise multiplication algorithm is optimized with the primitive instruction of RISC-V processor, which improved the performance of 256-bit and 512-bit multiplication by 19% and 8% than previous works, respectively. Lastly, we suggest the instruction extension for the high-speed multiplication on the RISC-V processor.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.3
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• pp.533-544
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• 2021

Using Shor algorithm, factoring and discrete logarithm problem can be solved effectively. The public key cryptography, such as RSA and ECC, based on factoring and discrete logarithm problem can be broken in polynomial time using Shor algorithm. NIST has been conducting a PQC(Post Quantum Cryptography) standardization process to select quantum-resistant public key cryptography. The multivariate quadratic based signature scheme, which is one of the PQC candidates, is suitable for IoT devices with limited resources due to its short signature and fast sign and verify process. We analyzes classic attacks and quantum attacks for Rainbow which is the only multivatiate quadratic based signature scheme to be finalized up to the round 3. Also we compute the attack complexity for the round 3 Rainbow parameters, and analyzes the security level of Rainbow, one of the PQC standardization candidates.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.837-842
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• 2010

In this paper, quantum cryptography systems used in the design process inevitably open bit stream of pseudo-random number that exists multiple open channels between them and the need to share information on the part of the situation exposes a pair of bit stream. In this paper, the base test of pseudo-random number I tested out this process and the merge bit binary column look out for randomness.

• Journal of Internet Computing and Services
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• v.20 no.3
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• pp.25-31
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• 2019

Along with the recent advances in quantum computers, it is anticipated that cryptographic attacks using them will make it insecure to use existing public key algorithms such as RSA and ECC. Currently, a lot of researches are underway to replace them by devising PQC (Post Quantum Cryptography) schemes. In this paper, we propose a performance enhancement method for Lizard implementation which is one of NIST PQC standardization submission. The proposed method is able to improve the performance by 7 ~ 25% for its algorithms compared to the implementation in the submission through the techniques of various implementation aspects. This study hopes that Lizard will become more competitive as a candidate for PQC standardization.

• ETRI Journal
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• v.45 no.6
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• pp.1090-1102
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• 2023

Authenticated multiple key agreement (AMKA) protocols provide participants with multiple session keys after one round of authentication. Many schemes use Diffie-Hellman or authenticated key agreement schemes that rely on hard integer factorizations that are vulnerable to quantum algorithms. Lattice cryptography provides quantum resistance to authenticated key agreement protocols, but the certificate always incurs excessive public key infrastructure management overhead. Thus, a lightweight lattice-based secure system is needed that removes this overhead. To answer this need, we provide a two-party lattice- and identity-based AMKA scheme based on bilateral short integer or computational bilateral inhomogeneous small integer solutions, and we provide a security proof based on the random oracle model. Compared with existing AMKA protocols, our new protocol has higher efficiency and stronger security.

• Journal of Integrative Natural Science
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• v.13 no.1
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• pp.8-12
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• 2020

In this paper we study the Minimum Error Discrimination problem (MED) for ensembles of linearly independent (LI) pure states. By constructing a map from the set on those ensembles we show that the Pretty Good Measurement (PGM) and the optimal measurement for the MED are related by the map.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.321-322
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• 2009