Linkable Message Tagging: Solving the Key Distribution Problem of Signature Schemes

8 years 12 days ago

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Digital signatures are one of the most extensively used cryptographic primitives today. It is well-understood that they guarantee practical security only if the corresponding veriﬁcation keys are distributed authentically; however, arguably, satisfying solutions for the latter haven’t been found yet, or at least aren’t in large-scale deployment. This paper introduces a novel approach for cryptographic message authentication where this problem does not arise: A linkable message tagging scheme (LMT) identiﬁes pairs of messages and accompanying authentication tags as related if and only if these tags were created using the same secret key. In other words, in contrast to signature schemes, our primitive does not aim at detecting whether individually considered messages originate from an explicitly speciﬁed entity, but instead decides whether all messages from a given collection originate from the same (possibly anonymous) source. The appealing consequence is that our primitive fu...

Felix Günther, Bertram Poettering

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