Secure provisioning of a portable device using a representation of a key

A portable device initially accesses a secure server and requests a certificate. The secure server generates a random key and encodes the generated key to generate a representation of the key, such as a two-dimensional bar code or an audio signal, and communicated to a local device, such as a laptop or desktop computer, using a web interface. The local device is used to present the representation of the key to a mobile device. The mobile device then captures the representation of the key from the local device, for example using an image capture device or audio capture device, and extracts the key by decoding the representation of the key. The key is then stored by the mobile device and used to securely communicate with the secure server without manually entering the key.