Let R = Q a2A R a be an innnite product of zero-dimensional chained rings. It is known that R is either zero-dimensional or innnite-dimensional. We prove that a nite-dimensional homomorphic image of R is of dimension at most one. If each R a is a PIR and if R is innnite-dimensional, then R admits one-dimensional homomorphic images. However, without the PIR hypothesis on the rings R a , we prese...

The growing popularity of cloud-based machine learning raises a natural question about the privacy guarantees that can be provided in such a setting. Our work tackles this problem in the context where a client wishes to classify private images using a convolutional neural network (CNN) trained by a server. Our goal is to build efficient protocols whereby the client can acquire the classificatio...

Key-homomorphic properties of cryptographic objects have proven to be useful, both from a theoretical as well as a practical perspective. Important cryptographic objects such as pseudorandom functions or (public key) encryption have been studied previously with respect to key-homomorphisms. Interestingly, however, signature schemes have not been explicitly investigated in this context so far. W...

The security of fully homomorphic encryption is often studied at the primitive level, and a lot of questions remain open when the cryptographer needs to choose between incompatible options, like INDCCA1 security versus circular security or search-to-decision reduction. The aim of this report is to emphasize the well known (and often underestimated) fact that the ability to compute every functio...

Key-homomorphic properties of cryptographic objects have proven to be useful, both from a theoretical as well as a practical perspective. Important cryptographic objects such as pseudorandom functions or (public key) encryption have been studied previously with respect to key-homomorphisms. Interestingly, however, signature schemes have not been explicitly investigated in this context so far. W...

Inbreeding in hermaphroditic plants can occur through two different mechanisms: biparental inbreeding, when a plant mates with a related individual, or self-fertilization, when a plant mates with itself. To avoid inbreeding, many hermaphroditic plants have evolved self-incompatibility (SI) systems which prevent or limit self-fertilization. One particular SI system-homomorphic SI-can also reduce...

Homomorphic Encryption is a recent promising tool in modern cryptography, that allows to carry out operations on encrypted data. In this paper we focus on the design of a scheme based on pairings and elliptic curves, that is able to handle applications where the number of multiplication is not too high, with interesting practical efficiency when compared to lattice based solutions. The starting...

Outsourced computations enable more efficient solutions towards practical problems that require major computations. Nevertheless, users’ privacy remains as a major challenge, as the service provider can access users’ data freely. It has been shown that fully homomorphic encryption schemes might be the perfect solution, as it allows one party to process users’ data homomorphically, without the n...

A trapdoor function is a one-way function with trapdoor, which is indispensable for getting a preimage of the function. In lattice-based cryptography, trapdoor function plays an important role in constructing the secure cryptographic schemes like identity-based encryption, homomorphic encryption, or homomorphic signature. There are three categories of trapdoor functions as standard trapdoor, lo...

In this paper, we construct subring homomorphic encryption scheme that is a homomorphic encryption scheme built on the decomposition ring, which is a subring of cyclotomic ring. In the scheme, each plaintext slot contains an integer in Zpl , rather than an element of GF(p) as in conventional homomorphic encryption schemes on cyclotomic rings. Our benchmark results indicate that the subring homo...