A method of post-manufacture generation of the device certificate 20 for verifying an electronic device 2 according to a public key infrastructure is provided. The method comprises obtaining, at a certificate generating apparatus 40, a first key 42 associated with the device 2. A second key 22 for the electronic device is derived from the first key 42. The device certificate 20 for the PKI is generated with the second key acting as the public key 22 associated with the device certificate 20. In a corresponding way a private key 24 for the PKI can be generated by the electronic device 2 based on a shared first key 42. This approach enables the manufacturing cost for manufacturing an electronic device to be reduced whilst still enabling use of a PKI for attesting to properties of the device 2.