Token Authorization

Hi, I'm a new user in freeRADIUS. I'd like to do a solution like token authentication. Firts step. User is authorized by user/password. Secound step: For the authentication from LDAP is taken further informations (like UID, date of birth) and user is asked about it. I think it is something familiar with CHAP Challenge but I don't know how to combine this solutions. Could somebody help me?? Greetings Krzysztof Kardas