Here’s a sample configuration file for HTTP digest authentication with Spring Security 3.0.x. Have a look at the xml comments for details.
The configuration was produced following the guidance given in Luke Taylor’s recent blog entry.
UPDATE: Apparently this can also be done using the security namespace like so:
<http entry-point-ref="digestAuthenticationEntryPoint">
<intercept-url pattern="/**" access="ROLE_USER" />
<custom-filter ref="digestAuthenticationFilter" position="BASIC_AUTH_FILTER" />
</http>
HTH,
Jukka