gistfile1.xml

<beans:bean id="userDetailsService" class="x.y.z.UserDetailsService" />
<beans:bean id="yubikeyAuthenticationProvider" 
    class="com.curlapp.yubikey.YubikeyAuthenticationProvider" 
    p:userDetailsService-ref="userDetailsService" 
    p:yubicoClientId="******" />

<authentication-manager alias="authenticationManager">
    <authentication-provider ref="yubikeyAuthenticationProvider"/>
</authentication-manager>