The blockchain, distributed and unalterable ledger, has lowered the cost of ownership records. This mechanism that required the involvement of notaries and was once reserved for expensive items can now be used for every type of assets. We propose to use it to keep track of the ownership of IoT devices. By registering devices and their transfer into the blockchain, we build a chain of ownership that can be used to prove ownership before a sale and transfer ownership after purchase, or to track and warn owners of security threats faced by their devices. Two extensions are proposed. The first one facilitates remote configuration and key management when a single owner must configure a great number of devices. The second one offers users information about an IoT device. That information can be used to create a discovery service, inform access decisions or keep track of a device's state