Proxy re-encryption (PRE) allows a proxy to convert a ciphertext encrypted under one key into an encryption of the same message under another key. The main idea is to place as little trust and reveal as little information to the proxy as necessary to allow it to perform its translations. At the very least, the proxy should not be able to learn the keys of the participants or the content of the ...

Multi-key fully homomorphic encryption (MFHE) schemes allow polynomially many users without trusted setup assumptions to send their data (encrypted under different FHE keys chosen by users independently of each other) to an honest-but-curious server that can compute the output of an arbitrary polynomial-time computable function on this joint data and issue it back to all participating users for...

Bitcoin smart contracts allow the development of new protocols on top of Bitcoin itself. This usually involves the definition of complex scripts, far beyond the requirement of a single signature. In this paper we introduce the concept of private key locked transactions, a novel type of transactions that allows the atomic verification of a given private key (belonging to an asymmetric key pair) ...

Symbolic encryption, in the style of Dolev-Yao models, is ubiquitous in formal security analysis aiming at the automated verification of network protocols. The näıve use of symbolic encryption, however, may unnecessarily require an expensive construction: an arbitrary-length encryption scheme that is private and non-malleable in an adaptive CCACPA setting. Most of the time, such assumptions rem...

As a de facto standard protocol, Internet protocol security (IPSec) provides secure communication between networked systems. One of the most common issues today in large-scale virtual private networks using IPSec is the problem of a stale security association, which occurs when the device at one end of the tunnel maintains the tunnel state but the other end does not. Internet key exchange (IKE)...