how secure is the web part property

[Tony Malandain]

Hi ng,

I have an authentication/authorization problem and I am thinking of
storing some sort of credentials (username/passwords and/or encryption
key) within a web part property.
How secure is it? Is there any way for a web part page or another web
part to access that information?

Another way to ask the question is: Where can I safely store information
that only my web part is entitled to access?

If it is not secure at all what would you suggest?
I can't use the SSO as the API is making no difference in term of which
web part is requesting the credentials (which by the way I find quite
astonishing!).

Thanks,
/Tony.