Anonymous access into SharePoint web services

Till now I didn’t find how to anonymous access web services, we can impersonate our SharePoint object model code by writing block of code under SPSecurity.Runwithelevatedprivileges method, I am looking for something like this for my web services code, I tried to find solution from internet, but I didn’t get success.

 

I can run or authenticate my web service code by passing current user credentials or any custom credentials (user name, password, domain name), but I am looking something different in authentication mode, please reply to me if any of you find some solutions or any alternatives for my challenge problem and I’ll also do same thing.

 

Thank you very much!