*20:50* [PhD][Update]
Diego F. Aranha: Efficient software implementation of elliptic curves and bilinear pairings
Name: Diego F. Aranha

Topic: Efficient software implementation of elliptic curves and bilinear pairings

Category:implementation

Description: The development of asymmetric or public key cryptography made possible new applications of cryptography such as digital signatures and electronic commerce. Cryptography is now a vital component for providing confidentiality and authentication in communication infra-structures. Elliptic Curve Cryptography is among the most efficient public-key methods because of its low storage and computational requirements. The relatively recent advent of Pairing-Based Cryptography allowed the further construction of flexible and innovative cryptographic solutions like Identity-Based Cryptography and variants. However, the computational cost of pairing-based cryptosystems remains significantly higher than traditional public key cryptosystems and thus an important obstacle for adoption, specially in resource-constrained devices.

The main contributions of this work aim to improve the performance of curve-based cryptosystems, consisting of:

(i) efficient implementation of binary fields in 8-bit microcontrollers embedded in sensor network nodes;

(ii) efficient formulation of binary field arithmetic in terms of vector instructions present in 64-bit architectures, and on the recently-introduced native support for binary field multiplication in the latest Intel microarchitecture families;

(iii) techniques for serial and parallel implementation of binary elliptic curves and symmetric and asymmetric pairings defined over prime and binary fields.

These contributions produced important performance improvements and, consequently, several speed records for computing relevant cryptographic algorithms in modern computer architectures ranging from embedded 8-bit microcontrollers to 8-core processors.

[...]

*09:04* [PhD][New]
Diego F. Aranha: Efficient software implementation of elliptic curves and bilinear pairings
Name: Diego F. Aranha

Topic: Efficient software implementation of elliptic curves and bilinear pairings

Category: implementation

Description: The development of asymmetric or public key cryptography made possible new applications of cryptography such as digital signatures and electronic commerce. Cryptography is now a vital component for providing confidentiality and authentication in communication infra-structures. Elliptic Curve Cryptography is among the most efficient public-key methods because of its low storage and computational requirements. The relatively recent advent of Pairing-Based Cryptography allowed the further construction of flexible and innovative cryptographic solutions like Identity-Based Cryptography and variants. However, the computational cost of pairing-based cryptosystems remains significantly higher than traditional public key cryptosystems and thus an important obstacle for adoption, specially in resource-constrained devices.\r\n

\r\nThe main contributions of this work aim to improve the performance of curve-based cryptosystems, consisting of:

(i) efficient implementation of binary fields in 8-bit microcontrollers embedded in sensor network nodes;

(ii) efficient formulation of binary field arithmetic in terms of vector instructions present in 64-bit architectures, and on the recently-introduced native support for binary field multiplication in the latest Intel microarchitecture families;

(iii) techniques for serial and parallel implementation of binary elliptic curves and symmetric and asymmetric pairings defined over prime and binary fields. \r\n

\r\nThese contributions produced important performance improvements and, consequently, several speed records for computing relevant cryptographic algorithms in modern computer architectures ranging from embedded 8-bit microcontrollers to 8-core processors.

[...]

*00:17* [Pub][ePrint]
Verifiable Computation over Encrypted Data in the Presence of Verification Queries, by Rosario Gennaro and Valerio Pastro
We consider the problem of a client who outsources the computation of a function $f$ over an input $x$ to a server, who returns $y=f(x)$. The client wants to be assured of the correctness of the computation and wants to preserve confidentiality of the input $x$ and possibly of the function $f$ as well. Moreover, the client wants to invest substantially less effort in verifying the correctness of the result than it would require to compute $f$ from scratch.This is the problem of secure outsourced computation over encrypted data. Most of the work on outsourced computation in the literature focuses on either privacy of the data, using {\\em Fully Homomorphic Encryption (FHE)}, or the integrity of the computation. No general security definition for protocols achieving both privacy and integrity appears in the literature. Previous definitions only deal with a very limited security model where the server is not allowed to

issue {\\em verification queries} to the client: i.e. it is not allowed to ``see\'\' if the client accepts or rejects the value $y$.

In this paper we present:

-- A formal definition of {\\em private and secure} outsourced computation {\\em in the presence of verification queries};

-- A protocol based on FHE that achieves the above definition for arbitrary poly-time computations;

-- Some additional protocols for the computation of {\\em ad-hoc} functions (such as the computation of polynomials and linear

combinations) over encrypted data. These protocols do not use the power of FHE, and therefore are much more efficient than the generic approach. We point out that some existing protocols in the literature for these tasks become insecure in the presence of verification queries, while our protocols can be proven in the stronger security model where verification queries are allowed.