DAGS:Key encapsulation using dyadic GS codes

Code-based cryptography is one of the main areas of interest for NIST's Post-Quantum Cryptography Standardization call. In this paper, we introduce DAGS, a Key Encapsulation Mechanism (KEM) based on quasi-dyadic generalized Srivastava codes. The scheme is proved to be IND-CCA secure in both random oracle model and quantum random oracle model. We believe that DAGS will offer competitive performance, especially when compared with other existing code-based schemes, and represent a valid candidate for post-quantum standardization.</p

Designing Efficient Dyadic Operations for Cryptographic Applications

Cryptographic primitives from coding theory are some of the most promising candidates for NIST's Post-Quantum Cryptography Standardization process. In this paper, we introduce a variety of techniques to improve operations on dyadic matrices, a particular type of symmetric matrices that appear in the automorphism group of certain linear codes. Besides the independent interest, these techniques find an immediate application in practice. In fact, one of the candidates for the Key Exchange functionality, called DAGS, makes use of quasi-dyadic matrices to provide compact keys for the scheme

SQUARE Attacks on Reduced-Round PES and IDEA Block Ciphers

This paper reports on variants of the Square attack applied to reduced-round versions of the PES and IDEA block ciphers . Attacks on 2.5 rounds of IDEA require 32 chosen-plaintexts and recover 77 key bits with a time complexity of 2 . A new kind of attack, the related-key Square attack, is applied to 2.5 rounds of IDEA and recovers 32 key bits, with two chosen-plaintexts and 2 related keys with a time complexity of 2 . Similar results hold for 2.5 rounds of PES. Implementations of the attacks on 32-bit block mini-versions of both ciphers confirmed the expected computational complexity. Although our attacks do not improve on previous approaches, this report shows new variants of the Square attack on word-oriented block ciphers like IDEA and PES

Improved SQUARE Attacks against Reduced-Round HIEROCRYPT

We present improved SQU.aw, attacks against the NESSIE candidate block ciphers HIEROCRYPT-3 and HIEROCRYPT-L1, designed by Toshiba. We improve over the previous best known attack on 2.5 rounds of HIEROCRYPT-3 by a factor of 2 28 computational steps with an attack on 3 rounds for 128-bit keys, and extend it to 3.5 rounds for longer keys. For HIEROCRYPT-L1 we are able to attack up to 3.5 out of 6.5 rounds

DAGS: Reloaded Revisiting Dyadic Key Encapsulation

In this paper we revisit some of the main aspects of the DAGS Key Encapsulation Mechanism, one of the code-based candidates to NIST’s standardization call for the key exchange/encryption functionalities. In particular, we modify the algorithms for key generation, encapsulation and decapsulation to fit an alternative KEM framework, and we present a new set of parameters that use binary codes. We discuss advantages and disadvantages for each of the variants proposed