An EPP Key (also known as an Auth Code or Authorisation Key) is an alpha-numeric code which is required to enable the transfer of Top Level Domains (.com, .net, .org, .biz or .info) from one registrar to another.
The EPP Key for your domain name must be provided to you promptly by your current registrar whenever you request it.
If you are asked to provide an EPP Key to anybody for any purpose other than changing the registrar for your domain name then you should query this request.