The random (geometric) key graph model is presented here. Each node randomly selects keys from a pool of keys and those keys form the key ring of each node. Two nodes within the given range (the radius of the yellow disk) are connected if they share a common key in their key ring.
For example, suppose node has the keys 1 and 2, node has the keys 2 and 3, and node has the keys 3 and 4. If , and are connected because they share the key 2. If , they are not connected. If , and are not connected because they do not share a key.