If I would like to exploit a used key by side-channel attack, one that measures electromagnetic fields, how many runs of the AES-128 do I need to spy on for a successful exploit?
I can't use any programs or software on that device. AES is software implemented. And I try (theoretically!) to spy in a distance of X meters. I am able to reduce the noise by surrounding emissions. But I can't have any type of access. So the attack model specifies using a sniffer.
I do not need an exact number of traces. There are only certain values for trace/distance that I could think of. I just found the TEMPEST attack, which needs 400k traces in a distance of 0.3 meters and 2.3m in 1 meter.