“…Gentry [Gentry, 2009] first proposed a Fully Homomorphic Encryption (FHE) scheme, which theoretically could compute any kind of arithmetic circuit, but is computationally intractable in practice. FHE evolved into more efficient schemes preserving addition and multiplication over encrypted data, such as BGV [Brakerski et al, 2011], FV [Fan and Vercauteren, 2012] or CKKS [Cheon et al, 2018], allowing approximations of multiplicative inverse, exponential and logistic function, or discrete Fourier transformation. Similar to asymmetric encryption, a public-private key pair (pub, priv) is generated.…”