Efficient Batched IBE from Lattices in the Standard Model

In this work, we present the first lattice-based construction of batched IBE in the standard model, whose security is proven under the succinct LWE assumption. Prior batched IBE schemes are only known either based on pairing-based assumptions or in the random oracle model. Moreover, our scheme is shown to be highly efficient, as the master public key, decryption key, and ciphertext are independent of the batch size B. Technically, we mainly rely on an insightful observation: batched IBE can be obtained solely from Inner-Product Encryption (IPE). To satisfy the efficiency requirements of batched IBE, we require an IPE scheme that owns two important features: decomposable key generation and compact components. Finally, we show how to construct such an IPE scheme from the well-known BGG+14 IPE scheme via careful modification.