Secure Metaweblog access for a web application

Hi, I’m developing a web application and would like wordpress users to be able have my web application post entries to their blog on their behalf.

It wouldn’t be ideal for them to store their blog password on my web application as even with cryptography it would be easy for a hacker to get at it if the server is compromised.

Even entering their password each time wouldn’t be secure.

Does wordpress have any method for trusted web applications to access a persons blog? Possibly a good idea would be for a user to be able to create a special password for metaweblog access restricted to requests from a specific domain. So that even if the password is got at it would be useless to anyone but the server.

Any Ideas?