Sebastian Schipp

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Symmetric encryption, secure hashing, and random number generation are essential operations for many cryptographic applications. Realizations of these functions usually aim for high computational speed. For some applications, however, low resource usage is more important. Thus, this work presents a compact design for symmetric encryption, hash function, and(More)
Secure multicast demands an efficient rekeying solution to update and to distribute the group key on every change in the group membership. This paper treats the authentication of rekeying messages with three new contributions. First, to accelerate group rekeying the Winternitz one-time signature scheme is applied to authenticate rekeying messages. Second, a(More)
Dittmann, Katzenbeisser, Schallhart and Veith (SEC 2005) introduced the notion of invertible media authentication schemes, embedding authentication data in media objects via invertible watermarks. These invertible watermarks allow to recover the original media object (given a secret encryption key), as required for example in some medical applications where(More)
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