Hashing into quadratic residues modulo a safe prime composite

ePrint Report: Hashing into quadratic residues modulo a safe prime composite

Sietse Ringers

For $n = pq$ a product of two safe primes, we construct and prove security of a cryptographic hash function $H$ mapping into the square residues $QR_n \subset (\mathbb{Z}/n\mathbb{Z})^*$, by squaring the output of an ordinary cryptographic hash function $H$ of sufficiently long output.

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