Method for providing end-to-end security of an interceptable communication between at least one first item of terminal equipment and one second item of terminal equipment , in which: - communication is established via a first intermediate server which communicates using a session initiation protocol allowing exchange of session keys, each item of terminal equipment using a session key to encrypt the communication data which it transmits, - the session keys are distributed by a key management server which communicates using a key management protocol, the method comprising at least the following steps, carried out by the first intermediate server: - reception of an invite message, transmitted by the first item of terminal equipment, according to the session initiation protocol, the invite message inviting the second item of terminal equipment and comprising a ticket according to the key management protocol, - transmission of the invite message to the second item of terminal equipment, - reception of a message of acceptance of the invite message comprising a result of ticket processing by the second item of terminal equipment, - transmission of the accept message to the first item of terminal equipment, characterised in that the method also comprises the following steps, carried out by the first intermediate server: - before transmitting the invite message to the second item of terminal equipment: ∘ saving the ticket received via the invite message, - before transmitting the accept message to the first item of terminal equipment: ∘ production of a ticket decode request message comprising: ▪ the saved ticket, ▪ the result of ticket processing, ∘ transmission of the decode request message destined for a second intermediate server, ∘ reception of a decode response comprising at least the session keys of the communication being established, ∘ recording the session keys by combining them with communication metadata. - communication is established via a first intermediate server which communicates using a session initiation protocol allowing exchange of session keys, each item of terminal equipment using a session key to encrypt the communication data which it transmits, - the session keys are distributed by a key management server which communicates using a key management protocol, - reception of an invite message, transmitted by the first item of terminal equipment, according to the session initiation protocol, the invite message inviting the second item of terminal equipment and comprising a ticket according to the key management protocol, - transmission of the invite message to the second item of terminal equipment, - reception of a message of acceptance of the invite message comprising a result of ticket processing by the second item of terminal equipment, - transmission of the accept message to the first item of terminal equipment, - before transmitting the invite message to the second item of terminal equipment: ∘ saving the ticket received via the invite message, - before transmitting the accept message to the first item of terminal equipment: ∘ production of a ticket decode request message comprising: ▪ the saved ticket, ▪ the result of ticket processing, ∘ transmission of the decode request message destined for a second intermediate server, ∘ reception of a decode response comprising at least the session keys of the communication being established, ∘ recording the session keys by combining them with communication metadata. ∘ production of a ticket decode request message comprising: ▪ the saved ticket, ▪ the result of ticket processing, ▪ the saved ticket, ▪ the result of ticket processing, ∘ transmission of the decode request message destined for a second intermediate server, ∘ reception of a decode response comprising at least the session keys of the communication being established, ∘ recording the session keys by combining them with communication metadata. <EOS>