Description
Secure multi-party computation (MPC) allows a set of $n$ players to securely compute an agreed function of their inputs, even when up to $t$ of the players are under complete adversarial control. We consider secure MPC in the information-theoretic model with broadcast channels (PKI setup) and present an efficient protocol with optimal resilience ($t< n/2$), using a new technique technique called dispute control: During the course of the protocol, the players keep track of disputes that arise among them, and the ongoing computation is adjusted such that known disputes cannot arise again. This prevents the faulty players from intervening too often, which again allows the honest players to reduce the frequency of expensive verifications. This way, we can securely (for some security parameter $\kappa$) compute a circuit with $m$ gates with communication complexity $O(m n^2 \kappa)$ bits (plus some overhead independent of $m$). This is to be compared with $\Omega(m n^{22} \kappa)$ -- the communication complexity of the best known protocol in the same model.
Prochains exposés
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Algorithms for post-quantum commutative group actions
Orateur : Marc Houben - Inria Bordeaux
At the historical foundation of isogeny-based cryptography lies a scheme known as CRS; a key exchange protocol based on class group actions on elliptic curves. Along with more efficient variants, such as CSIDH, this framework has emerged as a powerful building block for the construction of advanced post-quantum cryptographic primitives. Unfortunately, all protocols in this line of work are[…] -
Endomorphisms via Splittings
Orateur : Min-Yi Shen - No Affiliation
One of the fundamental hardness assumptions underlying isogeny-based cryptography is the problem of finding a non-trivial endomorphism of a given supersingular elliptic curve. In this talk, we show that the problem is related to the problem of finding a splitting of a principally polarised superspecial abelian surface. In particular, we provide formal security reductions and a proof-of-concept[…]-
Cryptography
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