Distance-bounding algorithms are a classical solution for the Relay Attack, wherein a verifier can determine an upper bound on its distance from the prover. However, recent literature is discussing the concept of mutual distance-bounding, where both sides of a transaction can measure this upper bound, to overcome the risk of a compromised or even malicious verifier. However, all these algorithms and proposed protocols, despite being theoretically promising, don't address how a mutual DB protocol, would be implemented in an RFID context; that is a passive RFID tag is one side of the transaction. How can this be done? How can we implement a time-keeping mechanisms on a passive RFID tag to have it approximate or restrict the distance to the verifier?