Abstract: An access method for accessing a protected communication service via a public communication network by using a secure communication network, whereby the secure communication network is based on user groups, including defining an access group having access to the communication service based on the user groups of the secure communication network, generating a group key for all members of the access group, providing the group key to a member of the access group via the secure communication network, and accessing the communication service via the public communication network using the group key, is provided. A communication system including a secure communication network based on user groups, a public communication network, a protected communication service, and an access server for managing access rights to the communication service, whereby the communication system implements the above method is further provided.

Abstract: The present invention relates to an access method for accessing a protected communication service via a public communication network by means of a secure communication network, whereby the secure communication network is based on user groups, comprising the steps of defining an access group having access to the communication service based on the user groups of the secure communication network, generating a group key for all members of the access group, providing the group key to a member of the access group via the secure communication network, and accessing the communication service via the public communication network using the group key. The present invention further relates to a communication system comprising a secure communication network based on user groups, a public communication network, a protected communication service, and an access server for managing access rights to the communication service, whereby the communication system is adapted to execute the above method.