Secure Mobile Client with Assertions for Access to Service Provider Applications

A Software-as-a-Service (SaaS) access control application on a client device is configured with a certificate that identifies a user, and with configuration information for one or more SaaS applications to access, and including an IDP identifier for the SaaS application. The SaaS access control application includes software to be inserted into a network software stack of the client device and software configured to serve as an identity provider for assertions. A request, made by an application on the client device to a SaaS service provider identified by a Universal Resource Locator (URL) provided during configuration of the SaaS access control application, is intercepted within the network software stack of the client device. The SaaS access control application generates an assertion based on the certificate and configuration information. The requesting application is caused to make a request to the SaaS service provider with the assertion embedded in the request.