He allowed himself to be swayed by his conviction that human beings are not born once and for all on the day their mothers give birth to them, but that life obliges them over and over again to give birth to themselves.
Gabriel García Márquez, ‘Love in the Time of Cholera’
‘Who are you?’ said the Caterpillar. Alice replied, rather shyly, ‘I – I hardly know, Sir, just at present – at least I know who I was when I got up this morning, but I think I must have been changed several times since then’.
Lewis Carroll, ‘Alice in Wonderland’
The development of software has recently changed significantly. Applications are typically distributed and built from a variety of components, which are themselves developed ad hoc, bought or outsourced. The context for which these applications are intended has also evolved: users have become mobile and access applications from diverse devices that are more vulnerable to theft, eavesdropping or other attacks. In addition, with the ubiquity of computing, users may need to access a wider range of applications, which may not be known to them in advance. The increasing importance of web or cloud services is another important factor. So in many cases there is a need for dynamic trust establishment and identity exchange protocols, and whatever security model is used must support these aspects.
A user may not be known in advance by the resource manager at the time of the request, and consequently their ...