Authenticating onto systems, connecting to mobile networks and providing identity data to access services is common ground for most EU citizens, however what is disruptive is that digital technologies fundamentally alter and upset the ways identity is managed, by people, companies and governments. Technological progress in cryptography, identity systems design, smart card design and mobile phone authentication have been developed as a convenient and reliable answer to the need for authentication. Yet, these advances ar enot sufficient to satisfy the needs across people's many spheres of activity: work, leisure, health, social activities nor have they been used to enable cross-border service implementation in the Single Digital Market, or to ensure trust in cross border eCommerce. The study findings assert that the potentially great added value of eID technologies in enabling the Digital Economy has not yet been fulfilled, and fresh efforts are needed to build identification and authentication systems that people can live with, trust and use. The study finds that usability, minimum disclosure and portability, essential features of future systems, are at the margin of the market and cross-country, cross-sector eID systems for business and public service are only in their infancy. This report joins up the dots, and provides significant exploratory evidence of the potential of eID for the Single Digital Market. A clear understanding of this market is crucial for policy action on identification and authentication, eSignature and interoperability.JRC.DDG.J.4-Information Societ