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We i n troduce a new cryptosystem with trapdoor decryption based on the diiculty of computing discrete logarithms in the class group of the non-maximal imaginary quadratic order O q , where q = q 2 , square-free and q prime. The trapdoor information is the conductor q. Knowledge of this trapdoor information enables one to switch t o a n d from the class(More)
We present a new non-interactive public-key distribution system based on the class group of a non-maximal imaginary quadratic order ClðD p Þ. The main advantage of our system over earlier proposals based on ðZ=nZÞ Ã [25,27] is that embedding id information into group elements in a cyclic subgroup of the class group is easy (straightforward embedding into(More)
Since nobody can guarantee that the computation of discrete logarithms in elliptic curves or IF p remains intractible for the future it is important to study cryptosystems based on alternative groups. A promising candidate, which was proposed by Buch-mann and Williams 8], is the class group C l(() of an imaginary quadratic order O. This ring is isomorphic(More)
—It is well known that the suitability of many cryptographic algorithms decreases with time. Hence, it is a challenging task to maintain the integrity, authenticity, confidentiality and availability of sensitive data over very long periods of time. A scalable approach to preserve the integrity and authenticity of archived data has been standardized in [12].(More)
Federated Single-Sign-On using web browsers as User Agents becomes increasingly important. However, current proposals require substantial changes in the implementation of the Relying-Party, and concentrate on functionality rather than security against real-world attacks like Cross Site Scripting (XSS) and Pharming. We therefore propose a different approach(More)
In 14] and 21] there are proposed ElGamal-type cryptosys-tems based on non-maximal imaginary quadratic orders with fast trap-door decryption. The trapdoor information is the factorization of the non-fundamental discriminant q = q 2. We will extend the ideas given there to set up Rabin and RSA analogues based on non-maximal imaginary quadratic orders. To(More)
Thep aper at hand discussest he design andi mplementationo ft he " Opene Card App " ,w hich is al ightweight ando pene ID client,w hich integrates majori nternationals tandards. It supports strong authenticationa nd electronic signatures with numerous common electronici dentity cardsi nd esktop as well as mobile environments.T he Open eCardA pp is designed(More)