Technique of determining a measure of proximity between two devices

An apparatus comprising a processor configured to:

• obtain a first device signature comprising an indication of a first point in time and a first parameter associated with the first point in time, wherein the first parameter is characteristic of a first measurement performed by a first sensor comprised in a first device;
• obtain a second device signature comprising an indication of a second point in time and a second parameter associated with the second point in time, wherein the second parameter is characteristic of a second measurement performed by a second sensor comprised in a second device;
• and
• determine, based on the first device signature and the second device signature, a measure of proximity between the first device and the second device.

A device comprising:

• a first sensor configured to perform a first measurement and generate first measurement data based on the first measurement;
• and
• a processor configured to:
• obtain the first measurement data from the first sensor;
• determine, based on the first measurement data, a first parameter associated with a first point in time, wherein the first parameter is characteristic of the first measurement;
• and
• generate a first device signature comprising an indication of the first point in time and the first parameter.