Identity-Based Key Verifiable Inner Product Functional Encryption Scheme

Functional encryption is a novel form of public key encryption that has captured significant attention since its inception, with researchers proposing a series of theoretical constructions. Functional encryption can be investigated for specific real-world applications such as the evaluation and output from the ciphertexts using the different decryption keys. In this paper, we investigate one of the more popular recent developments in functional encryption, i.e., inner product functional encryption. We address potential issues that inner product functional encryption might encounter in certain scenarios, including the inability to specify the identity of the ciphertext recipient, privacy leakage related to the master secret key vector, and the susceptibility of the decryption key to malicious tampering. In specific contexts, there might be a requirement for ciphertext recipients to be carefully designated. Malicious adversaries holding the decryption key can exploit it to gain insight into the master key or even alter the decryption key information. Consequently, key verification becomes necessary. To address this, we propose an identity-based key verifiable inner product functional encryption scheme (IBVE-IPE), which can effectively resolve the aforementioned issues and is validated for security and practicality through security proofs and performance analyses.