Methods and apparatus for providing proof of multiple entities being co-located at a specific time and location. An attestor transmits an attestation message via short range communication; the attestation message includes a time stamp, a location stamp, and a verifiable digital signature. An attestee that stores the attestation message can produce the attestation message at a later time to any interested party, as proof of co-location with the attestor at the specified time and location. In one exemplary embodiment, the methods and apparatus are substantially “open” for public implementation. Such public implementation enables attestors and attestees without prior affiliation, to provide attestation. Furthermore, the device-agnostic methods and apparatus can provide attestation capabilities even in previously deployed systems and devices.