The ongoing implementation of e-government has brought many governments to consider issuing digital identity cards. This thesis focuses on the impact of digital identity cards on the citizen’s privacy. Potential privacy threats are discussed and countermeasures that pertain to enhancing privacy are proposed. We advocate that digital identity should not solely be based on elements that disclose a citizens identity. Instead this thesis proposes a concept for digital identity cards that includes an anonymous component. This proposed approach is different from the approach taken by the current pro jects for digital identity cards. We propose a concept that comprises pseudonymous credentials as part of the citizen’s digital identity. We discuss current implementations of pseudonymous credential systems and consider problems resulting from the implementation in resource-restricted smart card environments. We discuss requirements for the use of credentials as part of the citizen’s digital identity. We discuss conceptual issues that must be addressed for a deployment of credentials. We consider the infrastructure that is necessary to support pseudonymous credentials. We discuss conceptual issues such as the choice of credential system, devices for the secure storage of credentials, non-transferability and revocation of digital credentials. An architecture is proposed that supports the use of the extended form of digital identity. We discuss barriers that must be overcome on the way to implementation. With the ongoing migration towards digital identity cards, we expect that privacy will become an issue of growing importance. This thesis contributes to the discussion on privacy in the domain of e-government and proposes anonymous services based on pseudonymous credentials as a means to alleviate potential privacy problems related to the use of electronic identity cards.