Multi-Party (Leveled) Homomorphic Encryption on Identity-Based and Attribute-Based Settings: Information security and cryptography - ICISC

We present constructions of CPA-secure (leveled) homomorphic encryption from learning with errors (LWE) problem. We use the construction introduced by Gentry, Sahai and Waters ‘GSW’ (CRYPTO’13) as building blocks of our schemes. We apply their approximate eigenvector method to our scheme. In contrast to the GSW scheme we provide extensions of the (leveled) homomorphic identity-based encryption (IBE) and (leveled) homomorphic attribute-based encryption (ABE) on the multi-identity and multi-attribute settings respectively. We realize the (leveled) homomorphic property for the multi-party setting by applying tensor product and natural logarithm. Tensor product and natural logarithm allow to evaluate different ciphertexts computed under different public keys. Similar to the GSW scheme, our constructions do not need any evaluation key, which enables evaluation even without the knowledge of user’s public key.SCOPUS: cp.k