Abstract: Identity and access control systems and methods employ a registry that receives a request for confidential data from a client, together with a secure enrollment profile identifier for the client, and generates and sends a challenge token to the client, which encrypts and returns the encrypted challenge token to the registry. Thereafter, the registry confirms that the encrypted challenge token is validly encrypted and calls up a security backend with authorization to provide the requested confidential data to client, and the security backend sends the requested confidential data to the client.