15. In an environment including at least one service provider each associated with a respective privacy policy, a non-transitory computer-readable medium having computer-executable instructions for execution by a processor, that, when executed, cause the processor to: manage a plurality of user identities of an individual user, the plurality of user identities pertaining to the individual user and describing different sets of personal information of the individual user, and to select one or more of the user identities of the user that satisfy a set of identity requirements of a security policy obtained from the environment; provide a plurality of privacy preferences relative to at least one user identity of the plurality of user identities of the user; evaluate one or more privacy preferences of the one or more selected user identities of the user against a privacy policy obtained from the environment to determine which of the selected user identities satisfy the at least one privacy preference; present the evaluation of the selected user identities to the user; and process, by a policy editor, a privacy policy from the environment, generate a reduced version thereof, and supply the reduced privacy policy as the privacy policy used by the privacy engine in performing the evaluation.
15. In an environment including at least one service provider each associated with a respective privacy policy, a non-transitory computer-readable medium having computer-executable instructions for execution by a processor, that, when executed, cause the processor to: manage a plurality of user identities of an individual user, the plurality of user identities pertaining to the individual user and describing different sets of personal information of the individual user, and to select one or more of the user identities of the user that satisfy a set of identity requirements of a security policy obtained from the environment; provide a plurality of privacy preferences relative to at least one user identity of the plurality of user identities of the user; evaluate one or more privacy preferences of the one or more selected user identities of the user against a privacy policy obtained from the environment to determine which of the selected user identities satisfy the at least one privacy preference; present the evaluation of the selected user identities to the user; and process, by a policy editor, a privacy policy from the environment, generate a reduced version thereof, and supply the reduced privacy policy as the privacy policy used by the privacy engine in performing the evaluation. 17. The non-transitory computer-readable medium of claim 15 , wherein the instructions further cause the processor to: provide at least one categorized group of user identity attributes; determine a privacy preference for each category; receive from the environment a security policy having requirements specifying required attributes; identify at least one category referencing the required attributes; and cause the evaluation operation to use the privacy preference of at least one identified category.