Communication
In OpenID there are two types of communication between OP and RP - direct and indirect.
Direct communication
During direct communication one side directly access second one.
This communication is used for:
- establishing association
- verifying authentication assertion
Indirect communication
Advantage of this way of communication is that user agent in redirect request to OP could add HTTP session information. It allows to identify user's browser at OP side.
This communication is used for:
- authentication request
- authentication response