A method of establishing a network by sharing a secret between a first entity (A) and a second entity (B), comprising the steps of: the first entity (A) broadcasting (100) an ANNOUNCE message announcing its identity and details of other entities it is aware of, wherein each of the other entities of which it is aware is associated with a particular nonce, and the message is encrypted using a broadcast encryption scheme common to the first and second entities (A,B), and; the second entity (B), upon receiving and decrypting the ANNOUNCE message, transmitting (110) to the first entity (A) a SHARE message, wherein the SHARE message comprises a signcryption of the secret, authenticated using signcryption data associated with the particular nonce associated with the second entity (B).