IACR News item: 21 May 2015
Shi Bai, Adeline Langlois, Tancr{\\`e}de Lepoint, Damien Stehl\
ePrint Report
The R\\\'enyi divergence is a measure of closeness of two
probability distributions. We show that it can often be used as an alternative
to the statistical distance in security proofs for lattice-based
cryptography. Using the R\\\'enyi divergence is particularly suited
for security proofs of primitives in which the attacker is required
to solve a search problem (e.g., forging a signature). We show that
it may also be used in the case of distinguishing problems (e.g.,
semantic security of encryption schemes), when they enjoy a public
sampleability property. The techniques lead to security proofs for
schemes with smaller parameters, and sometimes to simpler security
proofs than the existing ones.
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