To take advantage of various unique services, users often create identities on multiple Social Computing Systems (SCS). To ease social sharing, many users connect multiple accounts to export content from one system to another (e.g. sharing recommendations from Yelp on Facebook). This generates ambiguities for the administration of privacy policies in that content might be posted to one service but accessed through another. This shared access is a challenge when protection policies may not perfectly match; how can the destination platform access and emulate the protection guaranteed by the originating platform, without breaching the privacy of the user?
The ‘Default Policies’ approach recognizes that most users will likely not independently specify a shared access policy for all content and so provides common and accepted standards. In this approach, SCS policies are not hidden, but rather publicly known. Each SCS determines whether the policies of other sites are trusted or not; in order to be deemed ‘safe’, the policy must ensure inputs are nondeducible – that is, they must remain private.
Secure Multiparty Computation can be used to protect the content that is shared across social computing sites. This method safeguards both user information and the protection states of the SCS. Both are desirable outcomes in a secure federated computing system.
Linking accounts online reduces security through dependency; mechanisms for determining the risk of a link can assist in managing the security of these arrangements.