Trust discovery in a communications network

A mobile communications node for use in a communications network, the node comprising:

• a receiver for receiving from a network node authentication data unique to the node from which a compact representation of verification data for the node can be derived, and a compact representation of verification data of all nodes in the network, the compact representation of verification data of all nodes in the network being certified by the network node;
• a processor for deriving trust information from the authentication data;
• and
• a transmitter for sending to a second node the trust information and at least a part of the authentication data, the trust information usable by the second node to verify the authenticity of the message using the compact representation of verification data of all nodes in the network and the received trust information and authentication data.

A mobile communications node for use in a communications network, the node comprising:

• a receiver for receiving from a network node a compact representation of verification data of all nodes in the network certified by the network node;
• a memory for storing the received compact representation of verification data of all nodes in the network certified by the network node;
• the receiver being further arranged to receive from an advertising node a message, the message including authentication data and trust information derived from authentication data for the advertising node;
• and
• a processor for verifying the authenticity of the message using the compact representation of verification data of all nodes in the network, the received trust information and the received authentication data for the advertising node.