In a specific configuration file of his mobile application, the user will have URL and a name of XKMS server defined during the registration process. 3. The user will start the secure mobile application and start a procedure for generating asymmetric public/private key pair. The generated asymmetric private key will be protected by a separate PIN code defined by the user. The key pair could be generated inside the secure mobile application or could be generated on the SIM PKI smart card of the mobile phone. 4. The user will generate a Register XKMS request to assert a binding of informa- tion to the generated public key and send it to the registration service of the XKMS server. The registration of a key binding will result in the issue of a PKI certificate. The registration service will require additional information to authenticate this request which should be provided by the client-the XKMS authentication code and a Proof of Possession of the private key. The <Prototype- KeyBinding> element contains the public key that has to be registered. The <ProofOfPossession> element contains an XML Signature element. The user's private key-a cryptographic pair with the public key contained within the <PrototypeKeyBinding> is used to create the signature. 5. On receiving the registration request, the registration service of the XKMS server will verify the XKMS authentication code and the Proof of Possession information provided. 6. If the registration service accepts the request, a corresponding PKI certificate will be generated and key binding will be registered. 7. On receiving a registration result message from the XKMS server, the secure mobile application will verify the XML signature of the received message and validate the received PKI certificate. 8. If the mentioned verifications are successful, the secure mobile application will store the received PKI certificate in a Record Management System (RMS) of the mobile application. We considered a Web Service scenario where the mobile phone user produces a cryptographi