registration agreement on revenu site ( property)

Hi, I am purchasing a revenue land in Bangalore India, and currently the registration are closed as per government rules, because of this the owner of the land has suggested to do an "registration agreement" He also told that I will get my details on EC document and he said by this agreement 90% land will be mine and later he will sign when registration opens back, how can I proceede on this? Can this be possible? And safe?