Electronic transactions - be it between Public Administrations, citizens or businesses (for example G2C, G2B, B2B) - depend upon solving two kinds of issues: 

1. The authentication of the personal identity of the parties involved (whom am I actually dealing with?); 
2. The determination of the role, status, entitlements, or other socio-economic attributes of the individual (for example, is this person a registered student or a member of a medical or engineering association? Is this person entitled to sign a contract or represent a firm? etc.)

The knowledge of one's roles and entitlements, as a foundation of trust and legitimacy, is essential for many administrative and business transactions.

However, while the identity of a person is essentially a permanent feature, other attributes tend to change, often suddenly and unexpectedly, over time. Besides, the information on such events is generated and held, in a highly dispersed way, by the wide range of private and public institutions that we cross in our lives. For this reason it is wise to separate the authentication and authorisation mechanisms as much as is practicable.