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Auflistung nach Autor:in "Schlichtkrull, Anders"

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  • Konferenzbeitrag
    Accountable Trust Decisions: A Semantic Approach
    (Open Identity Summit 2020, 2020) Schlichtkrull, Anders; Mödersheim, Sebastian
    This paper is concerned with the question of how to obtain the highest possible assurance on trust policy decisions: when accepting an electronic transaction of substantial value or significant implications, we want to be sure that this did not happen because of a bug in a policy checker. Potential bugs include bugs in parsing documents, in signature checking, in checking trust lists, and in the logical evaluation of the policy. This paper focuses on the latter kind of problems and our idea is to validate the logical steps of the trust decision by another, complementary method. We have implemented this for the Trust Policy Language of the LIGHTest project and we use the completely independently developed FOL theorem prover RP_X as a complementary method.
  • Konferenzbeitrag
    Adapting the TPL Trust Policy Language for a Self-Sovereign Identity World
    (Open Identity Summit 2021, 2021) Alber, Lukas; More, Stefan; Mödersheim, Sebastian; Schlichtkrull, Anders
    Trust policies enable the automated processing of trust decisions for electronic transactions. We consider the Trust Policy Language TPL of the LIGHTest project [Mö19] that was designed for businesses and organizations to formulate their trust policies. Using TPL, organizations can decide if and how they want to rely on existing trust schemes like Europe’s eIDAS or trust scheme translations endorsed by them. While the LIGHTest project is geared towards classical approaches like PKI-based trust infrastructures and X.509 certificates, novel concepts are on the rise: one example is the self-sovereign identity (SSI) model that enables users better control of their credentials, offers more privacy, and supports decentralized solutions. Since SSI is based on distributed ledger (DL) technology, it is a question of how TPL can be adapted so that organizations can continue to enjoy the benefits of flexible policy descriptions with automated evaluation at a very high level of reliability. Our contribution is a first step towards integrating SSI and the interaction with a DL into a Trust Policy Language. We discuss this on a more conceptual level and also show required TPL modifications. We demonstrate that we can integrate SSI concepts into TPL without changing the syntax and semantics of TPL itself and have to add new formats and introduce a new built-in predicate for interacting with the DL. Another advantage of this is that the “business logic” aspect of a policy does not need to change, enable re-use of existing policies with the new trust model.