Decoding Generalized Reed-Solomon Codes and Its Application to RLCE Encryption Schemes

This paper compares the efficiency of various algorithms for implementing quantum resistant public key encryption scheme RLCE on 64-bit CPUs. By optimizing various algorithms for polynomial and matrix operations over finite fields, we obtained several interesting (or even surprising) results. For example, it is well known (e.g., Moenck 1976 \cite{moenck1976practical}) that Karatsuba's algorithm outperforms classical polynomial multiplication algorithm from the degree 15 and above (practically, Karatsuba's algorithm only outperforms classical polynomial multiplication algorithm from the degree 35 and above ). Our experiments show that 64-bit optimized Karatsuba's algorithm will only outperform 64-bit optimized classical polynomial multiplication algorithm for polynomials of degree 115 and above over finite field $GF(2^{10})$. The second interesting (surprising) result shows that 64-bit optimized Chien's search algorithm ourperforms all other 64-bit optimized polynomial root finding algorithms such as BTA and FFT for polynomials of all degrees over finite field $GF(2^{10})$. The third interesting (surprising) result shows that 64-bit optimized Strassen matrix multiplication algorithm only outperforms 64-bit optimized classical matrix multiplication algorithm for matrices of dimension 750 and above over finite field $GF(2^{10})$. It should be noted that existing literatures and practices recommend Strassen matrix multiplication algorithm for matrices of dimension 40 and above. All our experiments are done on a 64-bit MacBook Pro with i7 CPU and single thread C codes. It should be noted that the reported results should be appliable to 64 or larger bits CPU architectures. For 32 or smaller bits CPUs, these results may not be applicable. The source code and library for the algorithms covered in this paper are available at http://quantumca.org/

Shannon Perfect Secrecy in a Discrete Hilbert Space

The One-time-pad (OTP) was mathematically proven to be perfectly secure by Shannon in 1949. We propose to extend the classical OTP from an n-bit finite field to the entire symmetric group over the finite field. Within this context the symmetric group can be represented by a discrete Hilbert sphere (DHS) over an n-bit computational basis. Unlike the continuous Hilbert space defined over a complex field in quantum computing, a DHS is defined over the finite field GF(2). Within this DHS, the entire symmetric group can be completely described by the complete set of n-bit binary permutation matrices. Encoding of a plaintext can be done by randomly selecting a permutation matrix from the symmetric group to multiply with the computational basis vector associated with the state corresponding to the data to be encoded. Then, the resulting vector is converted to an output state as the ciphertext. The decoding is the same procedure but with the transpose of the pre-shared permutation matrix. We demonstrate that under this extension, the 1-to-1 mapping in the classical OTP is equally likely decoupled in Discrete Hilbert Space. The uncertainty relationship between permutation matrices protects the selected pad, consisting of M permutation matrices (also called Quantum permutation pad, or QPP). QPP not only maintains the perfect secrecy feature of the classical formulation but is also reusable without invalidating the perfect secrecy property. The extended Shannon perfect secrecy is then stated such that the ciphertext C gives absolutely no information about the plaintext P and the pad.Comment: 7 pages, 1 figure, presented and published by QCE202

Reinforcing Security and Usability of Crypto-Wallet with Post-Quantum Cryptography and Zero-Knowledge Proof

Crypto-wallets or digital asset wallets are a crucial aspect of managing cryptocurrencies and other digital assets such as NFTs. However, these wallets are not immune to security threats, particularly from the growing risk of quantum computing. The use of traditional public-key cryptography systems in digital asset wallets makes them vulnerable to attacks from quantum computers, which may increase in the future. Moreover, current digital wallets require users to keep track of seed-phrases, which can be challenging and lead to additional security risks. To overcome these challenges, a new algorithm is proposed that uses post-quantum cryptography (PQC) and zero-knowledge proof (ZKP) to enhance the security of digital asset wallets. The research focuses on the use of the Lattice-based Threshold Secret Sharing Scheme (LTSSS), Kyber Algorithm for key generation and ZKP for wallet unlocking, providing a more secure and user-friendly alternative to seed-phrase, brain and multi-sig protocol wallets. This algorithm also includes several innovative security features such as recovery of wallets in case of downtime of the server, and the ability to rekey the private key associated with a specific username-password combination, offering improved security and usability. The incorporation of PQC and ZKP provides a robust and comprehensive framework for securing digital assets in the present and future. This research aims to address the security challenges faced by digital asset wallets and proposes practical solutions to ensure their safety in the era of quantum computing

Chaves mais pequenas para criptossistemas de McEliece usando codificadores convolucionais

The arrival of the quantum computing era is a real threat to the confidentiality and integrity of digital communications. So, it is urgent to develop alternative cryptographic techniques that are resilient to quantum computing. This is the goal of pos-quantum cryptography. The code-based cryptosystem called Classical McEliece Cryptosystem remains one of the most promising postquantum alternatives. However, the main drawback of this system is that the public key is much larger than in the other alternatives. In this thesis we study the algebraic properties of this type of cryptosystems and present a new variant that uses a convolutional encoder to mask the so-called Generalized Reed- Solomon code. We conduct a cryptanalysis of this new variant to show that high levels of security can be achieved using significant smaller keys than in the existing variants of the McEliece scheme. We illustrate the advantages of the proposed cryptosystem by presenting several practical examples.A chegada da era da computação quântica é uma ameaça real à confidencialidade e integridade das comunicações digitais. É, por isso, urgente desenvolver técnicas criptográficas alternativas que sejam resilientes à computação quântica. Este é o objetivo da criptografia pós-quântica. O Criptossistema de McEliece continua a ser uma das alternativas pós-quânticas mais promissora, contudo, a sua principal desvantagem é o tamanho da chave pública, uma vez que é muito maior do que o das outras alternativas. Nesta tese estudamos as propriedades algébricas deste tipo de criptossistemas e apresentamos uma nova variante que usa um codificador convolucional para mascarar o código de Generalized Reed-Solomon. Conduzimos uma criptoanálise dessa nova variante para mostrar que altos níveis de segurança podem ser alcançados usando uma chave significativamente menor do que as variantes existentes do esquema de McEliece. Ilustramos, assim, as vantagens do criptossistema proposto apresentando vários exemplos práticos.Programa Doutoral em Matemátic

Energy efficiency analysis of selected public key cryptoschemes

Public key cryptosystems in both classical and post-quantum settings usually involve a lot of computations. The amount as well as the type of computations involved vary among these cryptosystems. As a result, when the computations are performed on processors or devices, they can lead to a wide range of energy consumption. Since a lot of devices implementing these cryptosystems might have a limited source of power or energy, energy consumption by such schemes is an important aspect to be considered. The Diffie-Hellman key exchange is one of the most commonly used technique in the classical setting of public key cryptographic shceme, and elliptic curve based Diffie-Hellman (ECDH) has been in existence for more than three decades. An elliptic curve based post-quantum version of Diffie-Hellman, called supersingular isogeny based Diffie-Hellman (SIDH) was developed in 2011. For computations involved in ECDH and SIDH, elliptic curve points can be represented in various coordinate systems. In this thesis, a comparative analysis of energy consumption is carried out for the affine and projective coordinate based elliptic curve point addition and doubling used in ECDH and SIDH. We also compare the energy consumption of the entire ECDH and SIDH schemes. SIDH is one of the more than sixty algorithms currently being considered by NIST to develop and standardize quantum-resistant public key cryptographic algorithms. In this thesis, we use a holistic approach to provide a comprehensive report on the energy consumption and power usage of the candidate algorithms executed on a 64-bit processor

Using Reed-Solomon codes in the (U | U + V ) construction and an application to cryptography

International audience—In this paper we present a modification of Reed-Solomon codes that beats the Guruswami-Sudan 1 − √ R decoding radius of Reed-Solomon codes at low rates R. The idea is to choose Reed-Solomon codes U and V with appropriate rates in a (U | U + V) construction and to decode them with the Koetter-Vardy soft information decoder. We suggest to use a slightly more general version of these codes (but which has the same decoding performance as the (U | U + V)-construction) for being used in code-based cryptography , namely to build a McEliece scheme. The point is here that these codes not only perform nearly as well (or even better in the low rate regime) as Reed-Solomon codes, but also that their structure seems to avoid the Sidelnikov-Shestakov attack which broke a previous McEliece proposal based on generalized Reed-Solomon codes