Provided is a process for mobile-initiated authentications to web services. Credential values of the user are established within a trusted execution environment of the mobile device and representations are transmitted to a server. The user of the mobile device may authenticate with the mobile device to the server, which may convey access to a web-based service from a relying device. The server may pass credentials corresponding to the web-service received from the mobile device and verified to permit user access to the web-service to the relying device. The relying device presents credentials to the web-service to login, authenticate, or otherwise obtain user-level permission for the user on the relying device. The user of the mobile device may authenticate with the mobile device to the server, and may initiate the authentication process from the mobile device, without inputting credentials corresponding to the web-service on the relying device.