History of Cryptography -- The Contribution of E.B. Fleissner and A. Figl for Today’s Cryptography -- On the history of cryptography during WW2, and possible new directions for cryptographic research -- Public Key Cryptography -- Efficient Factoring Based on Partial Information -- A Public-Key Cryptosystem Based on Shift Register Sequences -- A Comment on Niederreiter’s Public Key Cryptosystem -- Implementation Study of Public Key Cryptographic Protection in an Existing Electronic Mail and Document Handling System -- Cryptanalysis of the Dickson-Scheme -- Simultaneous Security of Bits in the Discrete Log -- On Public-Key Cryptosystems Built Using Polynomial Rings -- Secret Key Cryptography -- Is the Data Encryption Standard a Group? (Preliminary Abstract) -- Two New Secret Key Cryptosystems -- Cryptanalysts Representation of Nonlinearly Filtered ML-Sequences -- Authorized Writing for “Write-Once” Memories -- Shiftregister Sequences and Related Topics -- On Functions of Linear Shift Register Sequences -- On Feedforward Transforms and p-Fold Periodic p-Arrays -- Generalized Multiplexed Sequences -- A Note on Sequences Generated by Clock Controlled Shift Registers -- Using Algorithms as Keys in Stream Ciphers -- On the Linear Complexity of Combined Shift Register Sequences -- Analysis of a Nonlinear Feedforward Logic for Binary Sequence Generators -- Linear Complexity and Random Sequences -- Cryptographic Systems and Applications -- Engineering Secure Information Systems -- The Chipcard — An Identification Card with Cryptographic Protection -- Encryption Needs, Requirements and Solutions in Banking Networks -- The Role of Encipherment Services in Distributed Systems -- Modeling of Encryption Techniques for Secrecy and Privacy in Multi-User Networks -- Full Encryption in a Personal Computer System -- Showing Credentials Without Identification -- Networks Without User Observability — Design Options -- The Verifiability of Two-Party Protocols -- The Practice of Authentication -- Message Protection by Spread Spectrum Modulation in a Packet Voice Radio Link.

The storage, routing and transmission of information, either in the form of digital data or of analog signals, plays a central role in modern society. To ensure that such information is protected from access by unauthorized persons is an important new challenge. The development of the theory and practical techniques needed to meet this challenge is the goal of current cryptological research. This research is highly varied and multidisciplinary. It is concerned with fundamental problems in mathematics and theoretical computer science as well as with the engineering aspects of complex information systems. Cryptology today ranks among the most active and interesting areas of research in both science and engineering. EUROCRYPT '85 maintained the tradition of the three previous workshops in this series (Paris 1984, Udine 1983, Burg Feuerstein 1982) with its emphasis on recent developments in cryptology, but also made a concerted effort to encompass more traditional topics in cryptology such as shift register theory and system theory. The many papers on these topics in this volume are witness to the success of this effort.