González Vasco, María IsabelPérez Del Pozo, Ángel LuisSuarez Corona, Adriana2023-12-132023-12-132018-01González Vasco, M. I., Pérez del Pozo, A. L., & Suárez Corona, A. (2018). Group key exchange protocols withstanding ephemeral‐key reveals. IET Information Security, 12(1), 79-86.1751-8709https://hdl.handle.net/10016/39077When a group key exchange protocol is executed, the session key is typically extracted from two types of secrets: long-term keys (for authentication) and freshly generated (often random) values. The leakage of this latter so-called ephemeral keys has been extensively analysed in the 2-party case, yet very few works are concerned with it in the group setting. The authors provide a generic group key exchange construction that is strongly secure, meaning that the attacker is allowed to learn both long-term and ephemeral keys (but not both from the same participant, as this would trivially disclose the session key). Their design can be seen as a compiler, in the sense that it builds on a 2-party key exchange protocol which is strongly secure and transforms it into a strongly secure group key exchange protocol by adding only one extra round of communication. When applied to an existing 2-party protocol from Bergsma et al., the result is a 2-round group key exchange protocol which is strongly secure in the standard model, thus yielding the first construction with this property.8eng© 2020 The Institution of Engineering and TechnologyGroup key exchangeCompilerEphemeral keysStrong securityresearch articleInformáticaMatemáticasTelecomunicacioneshttps://doi.org/10.1049/iet-ifs.2017.0131open access79186IET Information Security12AR/0000032346