The packet-pair technique is a widely adopted method to estimate the capacity of a path. The use of the packet-pair technique has been suggested in numerous applications including network management and end-to-end admission control. Recent observations also indicate that this technique can be used to fingerprint Internet paths. However, given that packet-pair measurements are performed in an open environment, end-hosts might try to alter these measurements to increase their gain in the network. In this paper, the authors explore the security of measurements based on the packet-pair technique.