Putting research papers online I am doing research on a topic related to an authentication technique. For my own convenience (and for the others), I'm doing all my research and putting everything on a webpage which I'll host on my personal website. I am more organized when there's an anchor link which takes me from text to the bibliography and when everything is online. 

It would be an added benefit and convenience if I can also put all the papers I refer to on the same website. Is it permissible to do so? For instance, I heard a professor even encourage putting the paper online (which was originally on arXiv. But then I actually paid for a paper from Springer, and I was wondering if I can use the same logic and just assume that it is legal to do so. My intention is only to aid myself and anyone else interested in my research to access the papers I referred to in my research.
It depends on the specific license the papers are under, but if you are talking about uploading the full text version of the article to your own website then most likely no it is not permissible to do this.

If they were your own papers, it is more likely that a journal allows you to do this, but still some will not and it is important to check the policies of the individual journals.

You could certainly put a bibliography on your own website though, and link to the journal articles from there, hosted at their original journals or preprints (DOI links would be a good way to do this).

As a practical matter, however, if you host these documents in some non-public place (like a private document or privately hosted password-protected site rather than a public web site), you are extremely unlikely to catch any grief. If they are public, however, you expose yourself.