*21:17* [Pub][ePrint]
A low complexity bit-parallel Montgomery multiplier based on squaring for trinomials , by Yin Li and Yiyang Chen
In this paper, we present a new bit-parallel Montgomery multiplier for $GF(2^m)$ generated with irreducible trinomials. A newly proposed divide-and-conquer approach is applied to simplify the polynomial multiplication while the Montgomery squaring is induced to simplify the modular reduction. Meanwhile, this design effectively exploits the overlapped elements in squaring and reduction operation to reduce the space complexity. As a result, the proposed multiplier has about 25\\% reduced space complexity compared with previous multipliers, with a slight increase of time complexity. Among five binary fields recommended by NIST for the ECDSA (Elliptic Curve Digital Signature Algorithm), there exist two fields, i.e., $GF(2^{409})$, $GF(2^{233})$,defined by trinomials. For these two fields, we show that our proposal outperforms the previous best known results if the space and time complexities are both considered.

*21:17* [Pub][ePrint]
Faster Maliciously Secure Two-Party Computation Using the GPU, by Tore Kasper Frederiksen and Thomas P. Jakobsen and Jesper Buus Nielsen
We present a new protocol for maliciously secure two-partycomputation based on cut-and-choose of garbled circuits using the recent idea of ``forge-and-loose\'\' which eliminates around a factor 3 of garbled circuits that needs to be constructed and evaluated. Our protocol introduces a new way to realize the \"forge-and-loose\" approach which avoids an auxiliary secure two-party computation protocol, does not rely on any number theoretic assumptions and parallelizes well in a same instruction, multiple data (SIMD) framework.With this approach we prove our protocol universally composable-secure against a malicious adversary assuming access to oblivious transfer, commitment and coin-tossing functionalities in the random oracle model.

Finally, we construct, and benchmark, a SIMD implementation of this protocol using a GPU as a massive SIMD device. The findings compare favorably with all previous implementations of maliciously secure, two-party computation.

*18:17* [Pub][ePrint]
Cryptanalysis of the MORE symmetric key fully homomorphic encryption scheme, by Boaz Tsaban and Noam Lifshitz
The fully homomorphic symmetric encryption scheme \\emph{MORE} encrypts keys by conjugation with a random invertible matrix over an RSA modulus.

We provide a two known-ciphertexts cryptanalysis recovering a linear dependence among

the two encrypted keys.