It is indeed possible to build a trustworthy system from untrustworthy components, but not by implementing the fault-tolerance and security separately. Separation of concerns just does not apply. This lectures will therefore discuss the role of threshold cryptography and weak computing models in building fault-tolerant and secure services.

TBA

In classical cryptography, one usually considers two actors, a sender and a receiver, who try to communicate secretly.These two actors have received the names Alice and Bob. Interactive cryptography covers the case where Alice and Bob are not alone. This is relevant to the general topic of the workshop, which is survivability and distributed systems.

In the talk, I will show how interactive cryptography has fostered recent research by covering two series of results: the first series is related to the question of sharing the power to decrypt/sign with the RSA cryptosystems; the second investigates group signatures, which allow to sign on behalf of a group. Both provide examples of work of practical and theoretical relevance, stemming from distributing cryptographic resources.