The domain authorization code (also it can be referred to as an Auth Code or an EPP Code) is a secret code that is necessary if you want to transfer a domain name. It's like a safeguard against unauthorized domain transfers. Every domain has a unique code which is assigned by the domain registrar. It can also be changed by them, so you can feel safe. Your domain will not be transferred without your permission! Keep in mind that EPP code is required only when transferring .com, .net, .org, .biz, .info and .us domain names or it depends on the domain registrar. If your domain name is different, you will not need the EPP code. Other security measures apply for different domains.