Two-Client Inner-Product Functional Encryption with an Application to Money-Laundering Detection
Paola de Perthuis, David Pointcheval · Proceedings of the 2022 ACM SIGSAC Conference on Computer and Communications Security · 2022
In this paper, we extend Inner-Product Functional Encryption (IPFE), where there is just a vector in the key and a vector in the single sender's ciphertext, to two-client ciphertexts. More precisely, in our two-client functional encryption scheme, there are two Data Providers who can independently encrypt vectors x and y for a data consumer who can, from a functional decryption key associated to a vector α, compute ∑αi xiyi = x ⋅ Diag(α) ⋅ yT. Ciphertexts are linear in the dimension of the vectors, whereas the functional decryption keys are of constant size. We study two interesting particular cases: