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schemes that would be vulnerable to linear algebra attacks were they
based on ``usual\" algebras as platforms.
We propose the first general-purpose construction that avoids all these drawbacks: it is efficient, it requires no user interaction whatsoever (except for data up- and download), and it allows evaluating any dynamically chosen function on inputs encrypted under different independent public keys. Our solution assumes the existence of two non-colluding but untrusted servers that jointly perform the computation by means of a cryptographic protocol. This protocol is provably secure in the semi-honest model. We demonstrate the applicability of our result in two real-world scenarios from different domains: Privacy-Preserving Face Recognition and Private Smart Metering. Finally, we give a performance analysis of our general-purpose construction to highlight its practicability.
Our main contribution is to show that if the secret key polynomials of the encryption scheme are selected from discrete Gaussians, then the public key, which is their ratio, is statistically indistinguishable from uniform over its range. We also show how to rigorously extend the encryption secret key into a signature secret key. The security then follows from the already proven hardness of the R-SIS and R-LWE problems.
Each 258-bit integer is represented as a polynomial with five,65 bit signed integer, coefficients . Exploiting this splitting we designed a pipelined 65-bit multiplier based on new Karatsuba-Ofman variant using non-standard splitting to fit to the Xilinx embedded digital signal processor (DSP) blocks.
Our architecture is able to compute 258-bit multiplication suitable for BN curves using only 11 in-built DSP blocks available on Virtex-6
Xilinx FPGA devices. It is the least DSP blocks consumption in the known literature. This work can be extended to efficiently compute pairings at higher security levels.
This thesis deals with the analysis and design of trusted computing platforms. Trusted computing technology is a relatively new enabling technology to improve the trustworthiness of computing platforms. With minor changes to the boot process and the addition of a new hardware security component, called TPM (Trusted Platform Module), trusted computing platforms offer the possibility to verifiably report their integrity to external parties (i.e., remote attestation) and to bind information to a specific platform (i.e., sealed storage).
The first part of this thesis mainly focuses on the analysis of existing trusted computing platforms. We analyze the functionality provided by the specifications of the TCG (Trusted Computing Group) and purely software-based alternatives. Based on this analysis we present an improvement to a software-based attestation scheme: we propose to measure the execution time of a memory checksum function locally (with the time stamping functionality of the TPM) instead of remotely (over the network).
We also study the resilience of trusted computing platforms against hardware attacks. We describe how attacks on the communication interface of the TPM can circumvent the measured boot process. The feasibility of these attacks is investigated in practice. Additionally we explore which operations should be targeted with a side channel attack to extracts the secret keys of a TPM.
The second part of this thesis addresses some of the challenges to implement trusted computing technology on embedded and recon?gurable devices. One of the main problems when integrating a TPM into a system-on-chip design, is the lack of on-chip reprogrammable non volatile memory. We develop schemes to securely externalize the non-volatile storage of a TPM. One scheme relies a new security primitive, called a reconfigurable physical unclonable function, and another extends the security perimeter of the TPM to the external memory with a cryptographic prot[...]