Encoding monomorphic and polymorphic types

Most automatic theorem provers are restricted to untyped logics, and existing translations from typed logics are bulky or unsound. Recent research proposes monotonicity as a means to remove some clutter. Here we pursue this approach systematically, analysing formally a variety of encodings that further improve on efficiency while retaining soundness and completeness. We extend the approach to rank-1 polymorphism and present alternative schemes that lighten the translation of polymorphic symbols based on the novel notion of “cover”. The new encodings are implemented, and partly proved correct, in Isabelle/HOL. Our evaluation finds them vastly superior to previous schemes

Polytopic Cryptanalysis

Standard differential cryptanalysis uses statistical dependencies between the difference of two plaintexts and the difference of the respective two ciphertexts to attack a cipher. Here we introduce polytopic cryptanalysis which considers interdependencies between larger sets of texts as they traverse through the cipher. We prove that the methodology of standard differential cryptanalysis can unambiguously be extended and transferred to the polytopic case including impossible differentials. We show that impossible polytopic transitions have generic advantages over impossible differentials. To demonstrate the practical relevance of the generalization, we present new low-data attacks on round-reduced DES and AES using impossible polytopic transitions that are able to compete with existing attacks, partially outperforming these

Practical Low Data-Complexity Subspace-Trail Cryptanalysis of Round-Reduced PRINCE

Subspace trail cryptanalysis is a very recent new cryptanalysis technique, and includes differential, truncated differential, impossible differential, and integral attacks as special cases. In this paper, we consider PRINCE, a widely analyzed block cipher proposed in 2012. After the identification of a 2.5 rounds subspace trail of PRINCE, we present several (truncated differential) attacks up to 6 rounds of PRINCE. This includes a very practical attack with the lowest data complexity of only 8 plaintexts for 4 rounds, which co-won the final round of the PRINCE challenge in the 4-round chosen-plaintext category. The attacks have been verified using a C implementation. Of independent interest, we consider a variant of PRINCE in which ShiftRows and MixLayer operations are exchanged in position. In particular, our result shows that the position of ShiftRows and MixLayer operations influences the security of PRINCE. The same analysis applies to follow-up designs inspired by PRINCE

Improved Key Recovery Attacks on Reduced-Round AES with Practical Data an d Memory Complexities

Determining the security of AES is a central problem in cryptanalysis, but progress in this area had been slow and only a handful of cryptanalytic techniques led to significant advancements. At Eurocrypt 2017 Grassi et al. presented a novel type of distinguisher for AES-like structures, but so far all the published attacks which were based on this distinguisher were inferior to previously known attacks in their complexity. In this paper we combine the technique of Grassi et al. with several other techniques in a novel way to obtain the best known key recovery attack on 5-round AES in the single-key model, reducing its overall complexity from about $2^{32}$ to less than $2^{22}$. Extending our techniques to 7-round AES, we obtain the best known attacks on AES-192 which use practical amounts of data and memory, breaking the record for such attacks which was obtained in 2000 by the classical Square attack

Legislative History: An Act Concerning the Operation of Emergency Medical Vehicles (SP482)(LD 1303)

https://digitalmaine.com/legishist114/2302/thumbnail.jp

Two-Face: New Public Key Multivariate Schemes

We present here new multivariate schemes that can be seen as HFE generalization having a property called `Two-Face\u27. Particularly, we present five such families of algorithms named `Dob\u27, `Simple Pat\u27, `General Pat\u27, `Mac\u27, and `Super Two-Face\u27. These families have connections between them, some of them are refinements or generalizations of others. Notably, some of these schemes can be used for public key encryption, and some for public key signature. We introduce also new multivariate quadratic permutations that may have interest beyond cryptography

Retour d'expérience sur les bassins d'orage en réseau unitaire: une solution pour limiter les rejets de temps de pluie

International audienceLe développement des systèmes d'assainissement s'appuie souvent sur des structures construites il y a plusieurs décennies. Ces systèmes font face à une augmentation des niveaux d'exigence qui leur sont assignés. Dans le viseur de l'arrêté de 2015 notamment, les performances par temps de pluie des systèmes de collecte. Un retour d'expériences sur les bassins d'orage mené par le Cerema fait le point sur les interrogations et les solutions trouvées par les gestionnaires. CONTEXTE DE L'ETUDE En collaboration avec l'AFB, le GEMCEA, le Ministère de la transition écologique et solidaire et les Agences de l'eau, le Cerema a réalisé un vaste retour d'expériences sur les bassins d'orage implantés sur les réseaux d'assainissement unitaires. L'objet de ce retour d'expériences était de voir, sur le terrain, comment les gestionnaires/exploitants avaient eu recours à cette technique pour optimiser le fonctionnement de leur système, notamment par temps de pluie, et de collecter des informations techniques et financières quant au fonctionnement, à la conception, au dimensionnement de ce type d'ouvrages. A travers une recherche bibliographique et de nombreux entretiens réalisés auprès de 17 maîtres d'ouvrage/exploitants, ce travail a aussi permis indirectement de recueillir les témoignages des personnes interrogées quant aux enjeux et aux problématiques auxquelles les services peuvent être confrontés, aux difficultés techniques rencontrées, souvent liées à leur contexte local, et à la façon dont les collectivités ont cherché à y remédier notamment par la construction de bassins d'orage. Le projet ayant débuté au 2nd semestre 2013 et s'étant terminé en 2018, nous avons ainsi pu être les témoins, un peu malgré nous, des interrogations des différents acteurs vis-à-vis des évolutions de la réglementation en matière d'assainissement : autosurveillance, diagnostic permanent, choix du critère de conformité du système de collecte, … ainsi que des conséquences des lois NOTRe 5 et MAPTAM 6 sur la répartition des compétences à court et moyen termes. Cette communication fait volontairement le choix de se focaliser sur les éléments recueillis qui concernent les enjeux et opportunités de l'autosurveillance et du diagnostic permanent, les démarches mises en place par les gestionnaires pour optimiser le fonctionnement de leur système et répondre aux nouveaux critères de conformité fixés par l'arrêté de 2015

The Exchange Attack: How to Distinguish Six Rounds of AES with 288.22^{88.2} chosen plaintexts

In this paper we present exchange-equivalence attacks which is a new cryptanalytic attack technique suitable for SPN-like block cipher designs. Our new technique results in the first secret-key chosen plaintext distinguisher for 6-round AES. The complexity of the distinguisher is about $2^{88.2}$ in terms of data, memory and computational complexity. The distinguishing attack for AES reduced to six rounds is a straight-forward extension of an exchange attack for 5-round AES that requires $2^{30}$ in terms of chosen plaintexts and computation. This is also a new record for AES reduced to five rounds. The main result of this paper is that AES up to at least six rounds is biased when restricted to exchange-invariant sets of plaintexts

Hydroxyapatite-based cements induce different apatite formation in radicular dentin

Objectives. To investigate crystallinity and ultrastructure of the formed hydroxyapatite at radicular cervical and apical dentin after being treated with three different canal sealers. Methods. Cervical and apical root dentin surfaces were treated with two experimental hydroxyapatite-based sealers, containing sodium hydroxide (calcypatite) or zinc oxide (oxipatite) and an epoxy resin-based canal sealer (AH Plus); gutta-percha without sealer was included as control. Dentin surfaces were studied by X-ray diffraction and transmission electron microscopy through selected area diffraction and bright-field imaging after 24 h and 12 m of storage. Results. Root cervical dentin treated with calcypatite and oxipatite produced poor crystallinity of new minerals, wide amorphous phase and non-stoichiometry. Reflections at the 002 plane and the corresponding diffraction rings attained lower values in the Scherrer equation and the Scherrer-Wilson equation in samples treated with both HAp-based sealers than in specimens without sealer or with AH Plus. At root cervical dentin treated with calcypatite, shorter and wider crystallite size formations and lower crystals grain size were found, if compared to those encountered at oxipatite treated dentin. Oxipatite attained improved crystallographic atomic order and less structural variation in both distances and angles. Apical dentin treated with oxipatite attained preferred grain orientation with polycrystalline lattices. Significance. The immature crystallites formed in dentin treated with calcypatite and oxipatite will account for high hydroxyapatite solubility and remineralizing activity. New polycrystalline formations encountered in apical dentin treated with oxipatite may also produce high mechanical performance.This work was supported by the Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER) Project MAT2017-85999-P