We reconsider the formalization of known-key attacks against ideal primitive-based block ciphers. This was previously tackled by Andreeva, Bogdanov, and Mennink (FSE 2013), who introduced the notion of known-key indifferentiability. Our starting point is the observation, previously made by Cogliati and Seurin (EUROCRYPT 2015), that this notion, which considers only a single known key available ...

We study a novel mechanism design model in which agents arrive sequentially and each in turn chooses one action from a set of actions with unknown rewards. The information that becomes available affects the incentives of an agent to explore and generate new information. We characterize the optimal disclosure policy of a planner whose goal is to maximizes social welfare. One interpretation for o...

Kb M Fall1*, Ak Diallo2, Y Toure3, HM B Daff4, SB Ndour3, NN Fall3, Biaye3, NS Sylla1 and O Thiam2 Author Affiliations 1Abdoul Aziz Sy « Dabakh » Hospital of Tivaoune, Senegal 2Lieutenant Colonel Mamadou DIOUF Regional Saint-Louis, 3Gynecological Obstetric Clinic Aristide Le Dantec, 4Amadou Sakhir Mbaye Center Louga, Received: February 04, 2022 | Published: 16, Corresponding author: Khalifa Bab...

We present XPX, a tweakable blockcipher based on a single permutation P . On input of a tweak (t11, t12, t21, t22) ∈ T and a message m, it outputs ciphertext c = P (m⊕∆1)⊕∆2, where ∆1 = t11k⊕t12P (k) and ∆2 = t21k⊕t22P (k). Here, the tweak space T is required to satisfy a certain set of trivial conditions (such as (0, 0, 0, 0) 6∈ T ). We prove that XPX with any such tweak space is a strong twea...

We thank Dr Mansour for her interest in our article and for her provocative questioning of the recommendations for use of progestogen-only contraceptives by women with systemic lupus erythematosus (SLE) who test positive for antiphospholipid antibodies. We are sensitive to any reductions in choice of contraceptive methods, particularly for women in whom pregnancy has significant health conseque...

A t-round key alternating cipher can be viewed as an abstraction of AES. It defines a cipher E from t fixed public permutations P1, . . . , Pt : {0, 1}n → {0, 1}n and a key k = k0‖ · · · ‖kt ∈ {0, 1}n(t+1) by setting Ek(x) = kt ⊕ Pt(kt−1 ⊕ Pt−1(· · · k1 ⊕ P1(k0 ⊕ x) · · · )). The indistinguishability of Ek from a random truly random permutation by an adversary who also has oracle access to the ...