Martin Stanek

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The security of iterated hash functions relies on the properties of underlying compression functions. We study highly efficient compression functions based on block ciphers. We propose a model for high-rate compression functions, and give an upper bound for the rate of any collision resistant compression function in our model. In addition, we show that(More)
Simultaneous contract signing is a two-party cryptographic protocol: two mutually suspicious parties wish to exchange signatures on a contract. We propose novel and efficient protocol for contract signing based on a construction by Even, Goldreich, and Lempel. We focus on the reduction of on-line computational complexity of the protocol. A significant part(More)
Cryptology is a mathematical hard core of information security, since many of the information security problems (e.g. confidentiality, integrity, authenticity of information) can be (and often are) solved by means of cryptographical tools/algorithms. We analyse 20 selected academic courses in cryptology with respect to their aims, scopes, contents,(More)
Designated verifier signature schemes allow a signer to convince only the designated verifier that a signed message is authentic. We define attack models on the unforgeability property of such schemes and analyze relationships among the models. We show that the no-message model, where an adversary is given only public keys, is equivalent to the model, where(More)