An Adaptively Secure Mix-Net Without Erasures

Removing Erasures with Explainable Hash Proof Systems

An important problem in secure multi-party computation is the design of protocols that can tolerate adversaries that are capable of corrupting parties dynamically and learning their internal states. In this paper, we make significant progress in this area in the context of password-authenticated key exchange (PAKE) and oblivious transfer (OT) protocols. More precisely, we first revisit the noti...

Adaptively Secure Threshold Cryptography: Introducing Concurrency, Removing Erasures (Extended Abstract)

Adaptively Secure Two-Party Computation with Erasures

In the setting of multiparty computation a set of parties with private inputs wish to compute some joint function of their inputs, whilst preserving certain security properties (like privacy and correctness). An adaptively secure protocol is one in which the security properties are preserved even if an adversary can adaptively and dynamically corrupt parties during a computation. This provides ...

Adaptively Secure Threshold Cryptography without the Assumption of Erasure

We exhibit eecient threshold cryptosystems which are secure against adaptive adversaries even when the players cannot erase their local data. Speciically, we present erasure-free adaptively-secure protocols for distributed decryption in Cramer-Shoup cryptosystem. Our techniques are also applicable for distributing the secret-key operation of other cryptosystems, like RSA, DSS, and ElGamal, as w...

A Mix-Net from Any CCA2 Secure Cryptosystem

We construct a provably secure mix-net from any CCA2 secure cryptosystem. The mix-net is secure against active adversaries that statically corrupt less than λ out of k mix-servers, where λ is a threshold parameter, and it is robust provided that at most min(λ− 1, k − λ) mix-servers are corrupted. The main component of our construction is a mix-net that outputs the correct result if all mix-serv...