1. A method of dynamically assigning a role to a user in a distributed computing environment, said method comprising the steps of: a computer determining current values of one or more pre-defined attributes, each attribute of said one or more pre-defined attributes representing a trust level of said distributed computing environment to an aspect of an operational environment of said user; said computer calculating a current level of trust for said user, said current level of trust based on said current values of said one or more pre-defined attributes; and said computer assigning a role to said user based on said current level of trust and a pre-defined threshold value corresponding to said role; wherein said role belongs to a pre-defined hierarchical set of roles comprising a default role and one or more roles available to said user; and wherein said role is lower than or equal to a highest role available to said user in said hierarchical set of roles.