A system for providing secured access to an application service includes a
challenge provider that uses a first cryptographic technique to provide a
challenge to a client seeking access to an application service. The
client uses a second cryptographic technique to generate a response, and
provides the response to an authentication service. The authentication
service grants the client access to the application service only if the
challenge and response are authenticated using a first authentication
technique complementary to the first cryptographic technique and a second
authentication technique complementary to the second cryptographic
technique, respectively.