Almighty knows what it is ,it is touching elephant with closing eyes and guessing how it looks like.
The best suggested by HRD Ministry for educational certificate is your own state and then Ministry of Foriegn Affairs,Delhi.
It is big hassle .Fair would have the employer would have put direct to Embassy to validate and if not genuin punish the fraud,But the sysytem is so complex no body can answer how is perfcect.HRD of developing country who send people top work should come with some amicable solution.the best for you is talk withy Placement or employer what they are looking for.