Simulation-Secure Threshold PKE from LWE with Polynomial Modulus

ePrint Report: Simulation-Secure Threshold PKE from LWE with Polynomial Modulus

Daniele Micciancio, Adam Suhl

In LWE based cryptosystems, using small (polynomially large) ciphertext modulus improves both efficiency and security.
In threshold encryption, one often needs "simulation security": the ability to simulate decryption shares without the secret key.
Existing lattice-based threshold encryption schemes provide one or the other but not both.
Simulation security has seemed to require superpolynomial flooding noise,
and the schemes with polynomial modulus use Rényi divergence based analyses …

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