In today's distributed computing environments, like Grids and Clouds, authentication and authorization decisions take place in the middleware or on the compute and storage resources themselves. Thus, in both cases the decision is felled within the local network of the hosting organization. This is due to several drawbacks in common firewalls. For one, most firewalls only utilize the tupel of IP addresses, port numbers and protocol parameters to decide which connection are legitimate and which are not. This offers minimal configurability, which in complex environments like the Grid or the Cloud is not sufficient for optimal fine grained decisions. Also, the inability of application level firewalls to deal with dynamically opened server ports for encrypted connections like they are in use by GridFTP require very lax firewall rules to be set, if the Grid or Cloud is to operate unhindered.

In modern grids, authentication is usually implemented via an X.509 PKI (public key infrastructure). Proxy certificates are employed to facilitate interaction with the grid, especially for purposes of delegation and single sign-on. We propose modifications to the grid security infrastructure that allow reporting of proxy usage information to a database, giving the end user an opportunity to review by whom and for which purpose his credentials were used. By means of a standardized protocol for certificate revocation, they can then revoke affected proxies and stop abuse.

To secure communication in Grids many efforts have been made regarding authentication and authorization. Due to some application requirements it is up to now recommended to open wide port ranges on firewalls. This configuration is commonly accepted as insecure. We present an approach to enhance the security of firewalled Grid components by a new method to dynamically authorize TCP connections on firewalls. The authorization decision relies on the authenticated identity of users or conveyed attribute assertions. Authentication information is transferred within the TCP three-way-handshake. To distinguish the authentication information from application data a new TCP option tcpauthn is introduced. The new method TCP-AuthN leads to a new paradigm in firewall operation as the firewall comes to the final decision to allow or reject/deny a connection after the third segment of the TCP three-way-handshake is verified. The firewall denies/rejects each connection on an individual basis depending on the user's proven identity.