International Association
for Cryptologic Research

In this work, we present the first construction of batched IBE scheme from lattices. The security is proven in the standard model under the succinct LWE assumption. Prior batched IBE schemes are only known from pairing-based assumptions. Moreover, our lattice-based batched IBE scheme is shown to be highly efficient, as the master public key, decryption key, and ciphertext are independent of the batch size $B$. In contrast, existing pairing-based schemes cannot provide the post-quantum security guarantee, and their master public keys have to scale with $B$.

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.