Hello, The OBC certificate for central government will be in a definite format. You can check out from this link http://www.ncbc.nic.in/User_Panel/UserView.aspx?TypeID=1176

Both the state and central certificates will be signed by the state authority only, So if you have your certificate in the above mentioned format then your certificate will be valid for SSC. If not you will need to apply for a new one.

You can refer this link to know more details on the application process of SSC CHSL http://www.ncbc.nic.in/User_Panel/UserView.aspx?TypeID=1176

Hope this helps.