In this paper, we discuss the question how physical statements can be proven remotely over digital communication channels without using classical secret keys, and without assuming tamper-resistant and trusted measurement hardware in the location of the prover. Examples for the considered physical statements are: (i) “the temperature of a certain object is X◦C”, (ii) “two certain objects are pos...

One of the most extensively used technologies for improving security IoT devices is blockchain technology. It a new technology that can be utilized to boost security. decentralized peer-to-peer network with no central authority. Multiple nodes on mine or verify data recorded Blockchain. distributed ledger may keep track transactions between several parties. No one tamper since it unchangeable. ...

The well known Decisional Diffie-Hellman assumption states that given g, g and g, for random a, b, the element g is pseudo-random. Canetti in [Can97] introduced a variant of this assumption in which b is still random but a is drawn according to some well-spread distribution. In this paper we prove that his assumption holds in the generic group model and demonstrate its broad applicability in th...

The enumeration of m-resilient Boolean functions in n variables would be a quite useful information for cryptography. But it seems to be an intractable open problem. Upper and lower bounds have appeared in the literature in the mid 80s. Since then, improving them has been the goal of several papers. In this paper, we give a new upper bound which partially improves upon all the known bounds.

Oblivious transfer (OT, for short) [Rab81] is a fundamental primitive in the foundations of Cryptography. While in the standard model OT constructions rely on public-key cryptography, only very recently Kolesnikov in [Kol10] showed a truly efficient string OT protocol by using tamper-proof hardware tokens. His construction only needs few evaluations of a block cipher and requires stateless (the...

Cloud services providers practice security-induced lock-in when employing cryptography and tamper-resistance to limit the portability interoperability of users’ data applications. Moreover, anti-lock-in strategies intersect within context platform competition. When users deploy anti-lock in strategies, such as using a hybrid cloud, leader–follower pricing framework increases profits for cloud r...

Revelations over the past couple of years highlight the importance of understanding malicious and surreptitious weakening of cryptographic systems. We provide an overview of this domain, using a number of historical examples to drive development of a weaknesses taxonomy. This allows comparing different approaches to sabotage. We categorize a broader set of potential avenues for weakening system...

In the last few years we have concentrated our research efforts on new threats to the computing infrastructure that are the result of combining malicious software (malware) technology with modern cryptography. At some point during our investigation we ended up asking ourselves the following question: what if the malware (i.e., Trojan horse) resides within a cryptographic system itself? This led...

Although tamper-resistant devices are specifically designed to thwart invasive attacks, they remain vulnerable to micro-probing. Among several possibilities to provide data obfuscations, keyed hardware permutations can provide compact design and easy diversification. We discuss the efficiency of such primitives, and we give several examples of implementations, along with proofs of effectively l...

This paper proposes a cryptographic mechanism for metering the duration and/or the number of instances of running a data process. This mechanism has the following property: knowing a secret, one can validate a piece of metering evidence in constant units of time while without the secret the job of generating a valid piece of evidence requires time indicated by a value in the evidence. Because t...