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QcBits: Constant-Time Small-Key Code-Based Cryptography [chapter]

Tung Chou
2016 Lecture Notes in Computer Science  
This paper introduces a constant-time implementation for a quasi-cyclic moderate-density-parity-check (QC-MDPC) code based encryption scheme.  ...  Such speed is achieved by combining two techniques: 1) performing each polynomial multiplication in F2rxs{px r´1 q and Zrxs{px r´1 q using a sequence of "constant-time rotations" and 2) bitslicing.  ...  Introduction In 2012, Misoczki, Tillich, Sendrier, and Barreto proposed to use QC-MDPC codes for code-based cryptography [3] .  ... 
doi:10.1007/978-3-662-53140-2_14 fatcat:ou2uvilhxvhadkupskj6e7jcsq

A Side-Channel Assisted Cryptanalytic Attack Against QcBits [chapter]

Mélissa Rossi, Mike Hamburg, Michael Hutter, Mark E. Marson
2017 Lecture Notes in Computer Science  
QcBits is a code-based public key algorithm based on a problem thought to be resistant to quantum computer attacks.  ...  In this paper, we present a key recovery attack against QcBits.  ...  QcBits is an implementation of a variant of this protocol due to Chou in [13] . It operates in a constant time and has very good speed results and small keys sizes.  ... 
doi:10.1007/978-3-319-66787-4_1 fatcat:prugodyqk5etrnk3byjtj4ruo4

Novel Side-Channel Attacks on Quasi-Cyclic Code-Based Cryptography

Bo-Yeon Sim, Jihoon Kwon, Kyu Young Choi, Jihoon Cho, Aesun Park, Dong-Guk Han
2019 Transactions on Cryptographic Hardware and Embedded Systems  
Chou suggested a constant-time implementation for quasi-cyclic moderatedensity parity-check (QC-MDPC) code-based cryptography to mitigate timing attacks at CHES 2016.  ...  We further propose a singletrace attack which can even work when using ephemeral keys or applying Rossi et al.'s DPA countermeasures.  ...  Implementation of QC-MDPC Decoding QcBits, proposed by Chou [Cho16], is the constant-time implementation of QC-MDPC code-based cryptography to mitigate TAs.  ... 
doi:10.13154/tches.v2019.i4.180-212 dblp:journals/tches/SimKCCPH19 fatcat:yurx2sk42bdabpnirggnnds4fe

Error Amplification in Code-based Cryptography

Alexander Nilsson, Thomas Johansson, Paul Stankovski Wagner
2018 Transactions on Cryptographic Hardware and Embedded Systems  
Code-based cryptography is one of the main techniques enabling cryptographic primitives in a post-quantum scenario.  ...  In this paper we show a very fundamental and important property of code-based encryption schemes.  ...  Coding Theory and Public-Key Cryptography We review some basics from coding theory and show its application to public-key cryptography. Definition 1 (Linear codes).  ... 
doi:10.13154/tches.v2019.i1.238-258 dblp:journals/tches/NilssonJS19 fatcat:sxwmyf6wsbbhjizln2wmlsq35i

Survey on cryptanalysis of code-based cryptography: From theoretical to physical attacks

Vlad Dragoi, Tania Richmond, Dominic Bucerzan, Axel Legay
2018 2018 7th International Conference on Computers Communications and Control (ICCCC)  
Survey on cryptanalysis of code-based cryptography: from theoretical to physical attacks.  ...  prolemsD suh s omputing the disrete logrithm on n ellipti urve or ftoring ig integersF iven though these prolems re onsidered diult to solve with the help of lssil omputerD they n e solved in polynomil time  ...  Codes Cryptogr.D UQ@PAXTRI{TTTD PHIRF ghoIT ung ghouF QcBits: Constant-Time Small-Key Code-Based CryptographyD pges PVH{QHHF pringer ferlin reidelergD ferlinD reidelergD PHITF ghoIU ung ghouF McBits RevisitedD  ... 
doi:10.1109/icccc.2018.8390461 fatcat:mh2n2slpfzdtdf64vgnfgxngvq

Optimizing the Decoding Process of a Post-Quantum Cryptographic Algorithm

Antonio Guimarães, Diego F. Aranha, Edson Borin
2017 Anais do XVIII Simpósio em Sistemas Computacionais de Alto Desempenho (WSCAD 2017)   unpublished
QcBits is a state-of-the-art constant-time implementation of a code-based encryption scheme for post-quantum public key cryptography.  ...  Our implementation leverages SSE and AVX instructions extensions and performs 3.6 to 4.8 times faster than the original version, while preserving the 80-bit security level and constant time execution.  ...  More recently, Chou presented QcBits [Chou 2016 ], a constant-time implementation of a QC-MDPC code-based encryption scheme.  ... 
doi:10.5753/wscad.2017.247 fatcat:4gmut4e2tfhbhjms6pkalg5p4u

Efficient Hardware Implementation of the LEDAcrypt Decoder

Kristjane Koleci, Paolo Santini, Marco Baldi, Franco Chiaraluce, Maurizio Martina, Guido Masera
2021 IEEE Access  
INDEX TERMS Applied cryptography, post-quantum cryptography, hardware design, ASIC, FPGA, bit-flipping decoding, LDPC codes.  ...  This work describes an efficient implementation of the iterative decoder that is the main part of the decryption stage in the LEDAcrypt cryptosystem, recently proposed for post-quantum cryptography based  ...  Moreover, our implementation compares favorably with other code-based schemes proposed for PQC and is even faster than known realizations of classical public-key cryptography schemes like ECC or RSA.  ... 
doi:10.1109/access.2021.3076245 fatcat:tfus2ptqrbflhigu6eyjrstkma

QC-MDPC: A Timing Attack and a CCA2 KEM [chapter]

Edward Eaton, Matthieu Lequesne, Alex Parent, Nicolas Sendrier
2018 Lecture Notes in Computer Science  
Based on this study, we derive a timing attack.  ...  In 2013, Misoczki, Tillich, Sendrier and Barreto proposed a variant of the McEliece cryptosystem based on quasi-cyclic moderatedensity parity-check (QC-MDPC) codes.  ...  Introduction Code-based cryptography is almost as mature as public-key cryptography itself, dating back to 1978 with the invention of the original McEliece public-key encryption scheme [28] .  ... 
doi:10.1007/978-3-319-79063-3_3 fatcat:q4u3pjeydnemraa562j2522bqm

Optimizing BIKE for the Intel Haswell and ARM Cortex-M4

Ming-Shing Chen, Tung Chou, Markus Krausz
2021 Transactions on Cryptographic Hardware and Embedded Systems  
BIKE is a key encapsulation mechanism that entered the third round of the NIST post-quantum cryptography standardization process.  ...  Our M4 implementation is more than two times faster than the non-constant-time implementation portable written by the BIKE team.  ...  In particular, the QcBits paper [Cho16] was the first one to present a fully constant-time software implementation.  ... 
doi:10.46586/tches.v2021.i3.97-124 fatcat:oosixx6agjaldb4eddmjedsryu

Accelerating pre- and post-quantum cryptography [article]

T Tung Chou, DJ Daniel Bernstein, T Tanja Lange
2016
BW2 Cop. 36Gb QcBits: constant-time small-key code-based cryptography I.e., UC security [Can01] , which is impossible to achieve without some kind of trusted setup assumptions [CF01] .  ...  In the context of code-based cryptography, the permutations π and π −1 are known at key-generation time and are the same for every use of the secret key.  ...  Code-based encryption schemes are among the most promising candidates for postquantum public-key encryption. The security of a code-based encryption scheme relies on the code being used.  ... 
doi:10.6100/ir845487 fatcat:mni2l7q355blbd6hhgklvto4aa