The present invention relates to a device and method for generating an identification key using a process variation in a via process, and specifically the device for generating an identification key may include a first node provided in a semiconductor chip, a second node which is formed in a different layer from the first node, a via which is electrically shorted to the first node, and which is formed between the first node and the second node, the overlap distance between the second node and the via, in a pattern layout of the semiconductor chip, being adjusted to a value that is less than a threshold according to a design rule that ensures that the first node and the second node are shorted by the via, and a reader which provides an identification key by identifying whether the first node and the second node are shorted due to the via.