Site Security SHA-1 or MD5

Hi there

I’m now full-on with developing a new site to replace one I built some years ago with Dreamweaver. I’m using the same database and am currently working through the security provider extension. My database has the passwords stored with the SHA-1 hash and I think this is why my login form keeps giving the alert of incorrect password.

How do I tell the Security Provider to use SHA-1?

Cheers

Jon