The present disclosure is directed to an end-to-end secure communication system wherein, in addition to encrypting transmissions between clients, communication-related operations occurring within each client may also be secured. Each client may comprise a secure processing environment to process encrypted communication information received from other clients and locally-captured media information for transmission to other clients. The secure processing environment may include resources to decrypt received encrypted communication information and to process the communication information into media information for presentation by the client. The secure processing environment may also operate in reverse to provide locally recorded audio, image, video, etc. to other clients. Encryption protocols may be employed at various stages of information processing in the client to help ensure that information being transferred between the processing resources cannot be read, copied, altered, etc. In one example implementation, a server may manage interaction between clients, provision encryption keys, etc.