Session-based encryption keys

[helios]

I have some data I'd like to encrypt, but I'd like to not require entering a password. Is there any information that's only available when the user is logged-in? For example, a hash of their password (different from the one stored in the registry).
Alternatively, does Windows provide any encryption functions that use the session information?

[coder777]

Maybe the SID can help you:

https://msdn.microsoft.com/en-us/library/windows/desktop/aa379571%28v=vs.85%29.aspx

[helios]

The user SID is persistent, though.