Who: Elena Pagnin from Aarhus University, Denmark \
When: 10:00 - 11:00 Thursday {{ page.date | date_to_long_string }}\
Where: Room 8103, EDIT building.\
Title: {{ page.title }}
Abstract:\
We consider the problem of outsourcing computation on data authenticated by different users.
Our aim is to describe and implement the simplest possible solution to provide data integrity in cloud-based scenarios.
Concretely, our multi-key linearly homomorphic signature scheme (mklhs) allows users to upload signed data on a server,
and at any later point in time any third party can query the server to compute a linear combination of data authenticated
by different users and check the correctness of the returned result. Our construction generalizes Boneh et al.’s linearly
homomorphic signature scheme (PKC’09 [7]) to the multi-key setting and relies on basic tools of pairing-based cryptography.
Compared to existing multi-key homomorphic signature schemes, our mklhs is a conceptually simple and elegant direct construction,
which trades-off privacy for efficiency. The simplicity of our approach leads us to a very efficient construction that enjoys
significantly shorter signatures and higher performance than previous proposals. Finally, we implement mklhs using two
different pairing-friendly curves at the 128-bit security level, a Barreto-Lynn-Scott curve and a Barreto-Naehrig curve.
Our benchmarks illustrate interesting performance trade-offs between these parameters, involving the cost of exponentiation and
hashing inpairing groups.
We provide a discussion on such trade-offs that can be useful to other implementers of pairing-based protocols.
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