Authenticated Key Encapsulation Using Signatures

Maki Yoshida, Toru Fujiwara

Nina Bindel, Jacqueline Brendel, Marc Fischlin +2 more

Tatsuaki Okamoto

Guanhao Xue, Baocang Wang, Quanbo Qu +1 more

Abstract Authenticated key exchange protocol is widely applied in the Internet services. Lattice‐based key exchange protocols turn out to be quantum‐resistant and hence have attracted tremendous attention. A lattice‐based explicit authenticated key exchange protocol is constructed by combining an IND‐CPA key encapsulation mechanism with a strong EUF‐CMA digital signature under the message‐recovery mode. Concrete parameter specifications are suggested under the 102 and 218 bits post‐quantum security, respectively. Compared with the implicit authenticated key exchange derived directly from the key encapsulation mechanism, our proposals reduce the communication costs by 21.7% and 25.7%, respectively, under the same post‐quantum security level. Rough analysis shows that the proposals also obtain some advantages over previous constructions in term of computational efficiency. Moreover, our scheme achieves perfect forward secrecy while the original scheme only satisfies weak forward secrecy.

Edoardo Persichetti, Rainer Steinwandt, Adriana Suárez Corona

Assuming the availability of an existentially unforgeable signature scheme and an (IND- CCA secure) key encapsulation mechanism, we present a generic construction for group key establishment. The construction is designed with existing proposals for post-quantum cryptography in mind. Applied with such existing proposals and assuming their security, we obtain a quantum-safe three-round protocol for authenticated group key establishment that requires only one signature per protocol participant.

Matthew Campagna, Adam Petcher