Tampering of electronic equipment may be detected by instructing the electronic equipment to perform at least one computational operation at the electronic equipment, such as hashing of at least some of the memory of the electronic equipment, to produce a result. The result is received from the electronic equipment. Tampering of the electronic equipment is detected if the result is not received within a constrained time of the instructing, even if the result is correct. Tampering also may be detected if the result is not correct.