The usual advantages put forward for including nullability declarations in the type systems of programming languages are that they improve program reliability or performance. But there is another, entirely different, reason for doing so. In the right context, this information enables the software artifacts we produce, the objects and methods, to exhibit much greater malleability. For declarativ...

Due to the simplicity and performance of zk-SNARKs they are widely used in real-world cryptographic protocols, including blockchain smart contract systems. Simulation Extractability (SE) is a necessary security property for NIZK argument achieve Universal Composability (UC), common requirement such protocols. Most works that investigate SE focus on its strong variant which implies proof non-mal...

hadamard (or complete $cat(0)$) spaces are complete, non-positive curvature, metric spaces. here, we prove a nonlinear ergodic theorem for continuous non-expansive semigroup in these spaces as well as a strong convergence theorem for the commutative case. our results extend the standard non-linear ergodic theorems for non-expansive maps on real hilbert spaces, to non-expansive maps on had...

The breakthrough result of Chattopadhyay and Zuckerman (2016) gives a reduction from the construction of explicit two-source extractors to the construction of explicit non-malleable extractors. However, even assuming the existence of optimal explicit nonmalleable extractors only gives a two-source extractor (or a Ramsey graph) for poly(logn) entropy, rather than the optimal O (logn). In this pa...

The persistent educational challenges that fractions pose call for developing novel instructional methods to better prepare students fraction learning. Here, we examined the effects of a 24-session, Cuisenaire rod intervention on building block symbolic knowledge, continuous and discrete non-symbolic proportional reasoning, in children who have yet receive instruction. Participants were 34 seco...

In this report,based on the paper of Dziembowski et al.'s [DPW10], we explain how we can construct an e cient code that is nonmalleable with respect to modi cations that e ect each bit of the codeword arbitrarily. A variety of modi cations of codewords are considered such as ipping each bit of the codeword, leaving it untouched, or setting it to either 0 or 1 but independently of the value of t...

Until this point we have discussed encryptions that prevent a passive attacker from discovering any information about messages that are sent. In some situations, however, we may want to prevent an attacker from creating a new message from a given encryption. Consider an auction for example. Suppose the Bidder Bob is trying to send a message containing his bid to the Auctioneer Alice. Private ke...

Non-malleable commitments are a central cryptographic primitive that guarantee security against man-in-the-middle adversaries, and their exact round complexity has been a subject of great interest. Pass (TCC 2013, CC 2016) proved that non-malleable commitments with respect to commitment are impossible to construct in less than three rounds, via black-box reductions to polynomial hardness assump...

Since its introduction in the early 90’s, the notion of nonmalleability for encryption schemes has been formalized using a number of conceptually different definitional approaches—most notably, the “pragmatic” indistinguishability-based approach and the “semantical” simulation-based approach. We provide a full characterization of these approaches and consider their robustness under composition.