Kulikowski, DamianLangendörfer, PeterPiotrowski, KrzysztofDadam, PeterReichert, Manfred2019-10-112019-10-1120043-88579-380-6https://dl.gi.de/handle/20.500.12116/28773We present a new certificate revocation system for both on-line and off-line use, which is targeted to mobile-commerce systems. It allows to use certificates from any certificate issuer and to apply a proprietary revocation strategy. Our approach is well suited especially for location-aware services and mobile devices, because 1) our protocol reduces the amount of online communication, 2) the revocation tree is structured in such a way that certificates of services, which are located in the same region, can be verified using the same revocation proof.enText/Conference Paper1617-5468