(en) Authenticated two-party Diffie-Hellman key exchange allows two principals A and B, communicating over a public network, and each holding a pair of matching public/private keys to agréé on a session key. Protocols designed to deal with this problem ensure A (B resp.) that no other principals aside from B (A resp.) can learn any information about this value. These protocols additionally often ensure A and B that their respective partner has actually computed the shared secret value. A natural extension to the above cryptographie protocol problem is to consider a pool of principals agreeing on a session key. Over the years several papers hâve extended the two-party Diffie-Hellman key exchange to the multi-party setting but no formai treatments were carried out till recently. In light of recent developments in the formalization of the authenticated two-party Diffie-Hellman key exchange we hâve in this thesis laid out the authenticated group Diffie-Hellman key exchange on firmer foundations.