A trusted user circle server for encryption key distribution and authentication support, as well as a client-side application which resides on user's devices are disclosed. In particular, the trusted user circle server manages a repository for static public keys (SPUK) which are used for authentication and secure distribution of a dynamic private context key (DPCK) used for the end-to-many encryption. Accordingly, posting users encrypt posted document using the DPCK and viewing users retrieve the DPCK to decrypt the posted document. These keys are associated to the trusted user circle and are generated dynamically for a given circle policy context (CPC). The CPC is an identifier that represents a group of members of a trusted user circle. It changes whenever any member of the trusted user circle leave it, when a new trusted user circle is created or when the DPCK expires after a pre-determined period of time.