Algorithm to embed invisible roubust watermarking for images

I'm doing a project on invisible robust watermarking for image security. I have to develop algorithms to accomplish following tasks.

Construct watermark that cannot be totally removed from an image. Also i have to come up with an algorithm that provides ownership authenticity.

What algorithms that can be used to accomplish these tasks and also to embed invisible watermark to an image? Would be more helpful if you can suggest any samples/tutorials or useful websites on this regard.