Paillier

The Paillier cryptosystem, invented by and named after Pascal Paillier in 1999, is a probabilistic asymmetric algorithm for public key cryptography. The problem of computing n-th residue classes is believed to be computationally difficult. The decisional composite residuosity assumption is the intractability hypothesis upon which this cryptosystem is based.

The scheme is an additive homomorphic cryptosystem; this means that, given only the public-key and the encryption of ${\displaystyle m_{1}}$ and ${\displaystyle m_{2}}$, one can compute the encryption of ${\displaystyle m_{1}+m_{2}}$.

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