Code-based Cryptography is one of the main areas of interest for the Post-Quantum Cryptography Standardization call. In this paper, we introduce DAGS, a Key Encapsulation Mechanism (KEM) based on Quasi-Dyadic Generalized Srivastava codes. The scheme is proved to be IND-CCA secure in both Random Oracle Model and Quantum Random Oracle Model. We believe that DAGS will offer competitive performance...

We consider weak oblivious transfer (OT) from strong one-way functions and the paradigm of transforming unconditionally secure protocols in Maurer’s bounded storage model into computational secure protocols in the random oracle model. Weak OT is secure against adversaries which have a quadratic resource gap to honest parties. We prove that the random oracle can be replaced with strong one-way f...

This paper presents a simple and generic conversion from a publickey encryption scheme which is indistinguishable against chosen-plaintext attacks into a public-key encryption scheme which is indistinguishable against adaptive chosen-ciphertext attacks in the random oracle model. The scheme obtained by the conversion is as e cient as the original encryption scheme and the security reduction is ...

Random Oracles serve as an important heuristic for proving security of many popular and important cryptographic primitives. But, at the same time they are criticized due to the impossibility of practical instantiation. Programmability is one of the most important feature behind the power of Random Oracles. Unfortunately, in the standard hash functions, the feature of programmability is limited....

This paper presents results that show that there exist problems in that are provably hard in the generic group model but easy to solve whenever the random encoding function is replaced with a specific encoding function (or one drawn from a specific set of encoding functions). We also show that there exist cryptographic schemes that are provably hard in the generic group model but easy to break ...

We present a new signature whose security is reducible to a new assumptions about subgroups, the Computational Conjugate Subgroup Members (CCSM) Assumption, in the random oracle model.

Many cryptographic applications of hash functions are analyzed in the random oracle model. Unfortunately, most concrete hash functions, including the SHA family, use the iterative (strengthened) Merkle-Damgård transform applied to a corresponding compression function. Moreover, it is well known that the resulting “structured” hash function cannot be generically used as a random oracle, even if ...

At Eurocrypt 2005, Waters presented an identity based encryption (IBE) protocol which is secure in the full model without random oracle. In this paper, we extend Waters’ IBE protocol to a hierarchical IBE (HIBE) protocol which is secure in the full model without random oracle. The only previous construction in the same setting is due to Waters. Our construction improves upon Waters’ HIBE by sig...

Backes, Pfitzmann and Waidner showed in [7] that for protocols with hashes Dolev-Yao style models do not have cryptographically sound realization in the sense of BRSIM/UC in the standard model of cryptography. They proved that random oracle model provides a cryptographically sound realization. Canetti [9] introduced the notion of oracle hashing “towards realizing random oracles”. Based on these...