Handbook on Mobile and Ubiquitous Computing

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AB

C

1

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10

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D

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Figure 13.15 Delegation depth example.

We have also evaluated the overhead introduced by the AAS’s delegation depth parameter. In

order to make this more clear consider the example presented in Figure 13.15.

We have an AAS for the authority attribute (group, family_member) with a delegation depth

value of 0 (denoting no restrictions on the depth of delegation) and a membership threshold value

of 2. This AAS has as initial sources of authority the principals identified by the public keys A

and B. In step 1 principal A issues an AC for the authority attribute (group, family_member)

to principal C. This AC can be used by