Martin Stanek

Learn More
An important property of a hash function is the performance. We study fast iterated hash functions based on block ciphers. These hash functions and their compression functions are analyzed in the standard black-box model. We show an upper bound on rate of any collision resistant hash function. In addition, we improve known bound on the rate of collision(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)
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 highrate 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)