Friedrich L. Bauer – författare

Cryptology, for millennia a "secret science", is rapidly gaining in practical importance for the protection of communication channels, databases, and software. Beside its role in computerized information systems (public key systems), more and more applications within computer systems and networks are appearing, which also extend to access rights and source file protection. The first part of this book treats secret codes and their uses - cryptography. The second part deals with the process of covertly decrypting a secret code - cryptanalysis - where in particular advice on assessing methods is given. The book presupposes only elementary mathematical knowledge. Spiced with a wealth of exciting, amusing, and sometimes personal stories from the history of cryptology, it will also interest general readers. Decrypted Secrets has become a standard book on cryptology. This 4th edition has again been revised and extended in many technical and biographical details.

Dieses Buch über elementare Aussagenlogik (wie auch seine geplante Fortsetzung über Elementare Prädikatenlogik und Universelle Algebra) ist aus Vorlesungen an der Technischen Universität München entstanden. Es basiert auf der Überzeugung, daß für Studierende der Informatik nicht nur ein anderer Aufbau des mathematischen Grundstudiums geboten ist als etwa für Ingenieure oder Physiker, sondern auch ein anderes Menü, als es sich an unseren Universitäten nach den GAMM-NTG-Empfehlungen der siebziger Jahre eingebürgert hat. Neben den unentbehrlichen Einführungsvorlesungen in Mathematik sind für die Informatiker vor dem Vordiplom handwerkliche Grundkenntnisse in Logik und Universeller Algebra erforderlich - als Grundlage für die Praktische und die Theoretische Informatik im zweiten Studienabschnitt. Im Gegensatz zu vielen anderen Büchern über Logik ist dieses für den Anfänger der Informatik geschrieben und didaktisch auf sein Niveau eingestellt. Dabei sind sonst eher außerhalb der Aussagenlogik liegende Gegenstände wie die Schaltlogik systematisch einbezogen worden, wo immer es möglich war: von dem für die Programmiersprachen so wichtigen Gebiet der dyadischen Fallunterscheidungen über die Resolventenmethode, die den Anschluß an die Prädikatenlogik vorbereitet, bis zu modalen Aussagenlogiken. Die eingestreuten Übungsaufgaben greifen häufig Gedanken auf, die im Text nur nebenbei erwähnt sind, und stellen Querbezüge her. Die Lösungshinweise am Ende des Buches bieten manche Überraschungen.

Informatik. Eine einführende Übersicht hat sich als Standardwerk für das Studium der Informatik bewährt. Der vorliegende zweite Teil steht unter dem Leitgedanken "Strukturen", der das Grundthema "Algorithmen" des ersten Teils ergänzt. Zunächst werden Programmstrukturen und Datenstrukturen einschließlich der Techniken ihrer Implementierung behandelt. Sodann werden formale (Sprach-)Systeme, die zur Beschreibung solcher Strukturen dienen, auf relationentheoretischer Grundlage dargestellt. Ein weiteres Kapitel behandelt die Formalisierung der Syntax und der Semantik algorithmischer Sprachen, mit einem Abschnitt über abstrakte Datentypen. Den Abschluß bilden die Anhänge "Korrespondenzen und Funktionen", "Datenendgeräte" und "Zur Geschichte der Informatik" sowie Syntaxdiagramme für die ALGOL 68- und die PASCAL-Notation, die im Buch verwendet werden.

For some years, specification of software and hardwaresystems has been influenced not only by algebraic methodsbut also by new developments in logic. These newdevelopments in logic are partly based on the use ofalgorithmic techniques in deduction and proving methods, butare alsodue to new theoretical advances, to a great extentstimulated by computer science, which have led to new typesof logic and new logical calculi. The new techniques,methods and tools from logic, combined with algebra-basedones, offer very powerful and useful tools for the computerscientist, which may soon become practical for commercialuse, where, in particular, more powerful specification toolsare needed for concurrent and distributed systems.This volume contains papers based on lectures by leadingresearchers which were originally given at an internationalsummer school held in Marktoberdorf in 1991. The papers aimto give a foundation for combining logic and algebra for thepurposes of specification under the aspects of automateddeduction, proving techniques, concurrency and logic,abstract data types and operational semantics, andconstructive methods.

Die Kryptologie, eine jahrtausendealte "Geheimwissenschaft", gewinnt für den Informatiker zusehends praktische Bedeutung in Verbindung mit Datenbanken und Telekommunikation. Neben ihre Nutzung in rechnergestützten öffentlichen Nachrichtensystemen ("öffentliche Schlüssel") treten interne Anwendungen, die sich auch auf Zugriffsberechtigungen und den Quellenschutz von Software erstrecken. Der erste Teil des Buches handelt in elf Kapiteln von den Geheimschriften und ihrem Gebrauch - von der Kryptographie. Im zweiten Teil wird in elf weiteren Kapiteln das Vorgehen zum unbefugten Entziffern einer Geheimschrift - die Kryptanalyse - besprochen, wobei sich insbesondere Hinweise für die Verfahrensbeurteilung ergeben. Das Buch setzt nur elementare mathematische Kenntnisse voraus. Mit einer Fülle spannender, lustiger und bisweilen anzüglicher Geschichten aus der historischen Kryptologie gewürzt, ist es selbst für den Laien reizvoll zu lesen.

Die Kryptologie, eine jahrtausendealte "Geheimwissenschaft", gewinnt zusehends praktische Bedeutung für den Schutz von Kommunikationswegen, Datenbanken und Software. Neben ihre Nutzung in rechnergestützten öffentlichen Nachrichtensystemen ("public keys") treten mehr und mehr rechnerinterne Anwendungen, wie Zugriffsberechtigungen und der Quellenschutz von Software. - Der erste Teil des Buches behandelt die Geheimschriften und ihren Gebrauch - die Kryptographie. Dabei wird auch auf das aktuelle Thema "Kryptographie und Grundrechte des Bürgers" eingegangen. Im zweiten Teil wird das Vorgehen zum unbefugten Entziffern einer Geheimschrift - die Kryptanalyse - besprochen, wobei insbesondere Hinweise zur Beurteilung der Verfahrenssicherheit gegeben werden. Mit der vorliegenden dritten Auflage wurde das Werk auf den neuesten Stand gebracht. - Das Buch setzt nur mathematische Grundkenntnisse voraus. Mit einer Fülle spannender, lustiger und bisweilen anzüglicher Geschichten aus der historischen Kryptologie gewürzt, ist es auch für Laien reizvoll zu lesen.

Der Autor entwickelt unterhaltsam, gleichzeitig mit mathematischer Strenge, zahlreiche Facetten aus der Wissenschaftsgeschichte, die mit den Anfängen der Informatik in Zusammenhang stehen. Die Beiträge sind über viele Jahre im Informatik Spektrum erschienen und werden nun erstmals in einem Buch zusammengefasst. Die Informatik selbst ist eine junge Wissenschaft, deren Wurzeln tief in die Vergangenheit zurückreichen. Der Autor zeigt dies anhand vieler anregender historischer Notizen.

The Heinz Nixdorf Museum Forum (HNF) is the world’s largest c- puter museum and is dedicated to portraying the past, present and future of information technology. In the “Year of Informatics 2006” the HNF was particularly keen to examine the history of this still quite young discipline. The short-lived nature of information technologies means that individuals, inventions, devices, institutes and companies“age” more rapidly than in many other specialties. And in the nature of things the group of computer pioneers from the early days is growing smaller all the time. To supplement a planned new exhibit on “Software and Inform- ics” at the HNF, the idea arose of recording the history of informatics in an accompanying publication. Mysearchforsuitablesourcesandauthorsveryquickly cameupwith the right answer, the very rst name in Germany: Friedrich L. Bauer, Professor Emeritus of Mathematics at the TU in Munich, one of the - thers of informatics in Germany and for decades the indefatigable author of the“Historical Notes” column of the journal Informatik Spektrum. Friedrich L. Bauer was already the author of two works on the history of informatics, published in different decades and in different books. Both of them are notable for their knowledgeable, extremely comp- hensive and yet compact style. My obvious course was to motivate this author to amalgamate, supplement and illustrate his previous work.

The Heinz Nixdorf Museum Forum (HNF) is the world’s largest c- puter museum and is dedicated to portraying the past, present and future of information technology. In the “Year of Informatics 2006” the HNF was particularly keen to examine the history of this still quite young discipline. The short-lived nature of information technologies means that individuals, inventions, devices, institutes and companies“age” more rapidly than in many other specialties. And in the nature of things the group of computer pioneers from the early days is growing smaller all the time. To supplement a planned new exhibit on “Software and Inform- ics” at the HNF, the idea arose of recording the history of informatics in an accompanying publication. Mysearchforsuitablesourcesandauthorsveryquickly cameupwith the right answer, the very rst name in Germany: Friedrich L. Bauer, Professor Emeritus of Mathematics at the TU in Munich, one of the - thers of informatics in Germany and for decades the indefatigable author of the“Historical Notes” column of the journal Informatik Spektrum. Friedrich L. Bauer was already the author of two works on the history of informatics, published in different decades and in different books. Both of them are notable for their knowledgeable, extremely comp- hensive and yet compact style. My obvious course was to motivate this author to amalgamate, supplement and illustrate his previous work.

Cryptology, for millennia a "secret science", is rapidly gaining in practical importance for the protection of communication channels, databases, and software. Beside its role in computerized information systems (public key systems), more and more applications within computer systems and networks are appearing, which also extend to access rights and source file protection. The first part of this book treats secret codes and their uses - cryptography. The second part deals with the process of covertly decrypting a secret code - cryptanalysis - where in particular advice on assessing methods is given. The book presupposes only elementary mathematical knowledge. Spiced with a wealth of exciting, amusing, and sometimes personal stories from the history of cryptology, it will also interest general readers. Decrypted Secrets has become a standard book on cryptology. This 4th edition has again been revised and extended in many technical and biographical details.

The Heinz Nixdorf Museum Forum (HNF) is the world’s largest c- puter museum and is dedicated to portraying the past, present and future of information technology. In the “Year of Informatics 2006” the HNF was particularly keen to examine the history of this still quite young discipline. The short-lived nature of information technologies means that individuals, inventions, devices, institutes and companies“age” more rapidly than in many other specialties. And in the nature of things the group of computer pioneers from the early days is growing smaller all the time. To supplement a planned new exhibit on “Software and Inform- ics” at the HNF, the idea arose of recording the history of informatics in an accompanying publication. Mysearchforsuitablesourcesandauthorsveryquickly cameupwith the right answer, the very rst name in Germany: Friedrich L. Bauer, Professor Emeritus of Mathematics at the TU in Munich, one of the - thers of informatics in Germany and for decades the indefatigable author of the“Historical Notes” column of the journal Informatik Spektrum. Friedrich L. Bauer was already the author of two works on the history of informatics, published in different decades and in different books. Both of them are notable for their knowledgeable, extremely comp- hensive and yet compact style. My obvious course was to motivate this author to amalgamate, supplement and illustrate his previous work.

For some years, specification of software and hardwaresystems has been influenced not only by algebraic methodsbut also by new developments in logic. These newdevelopments in logic are partly based on the use ofalgorithmic techniques in deduction and proving methods, butare alsodue to new theoretical advances, to a great extentstimulated by computer science, which have led to new typesof logic and new logical calculi. The new techniques,methods and tools from logic, combined with algebra-basedones, offer very powerful and useful tools for the computerscientist, which may soon become practical for commercialuse, where, in particular, more powerful specification toolsare needed for concurrent and distributed systems.This volume contains papers based on lectures by leadingresearchers which were originally given at an internationalsummer school held in Marktoberdorf in 1991. The papers aimto give a foundation for combining logic and algebra for thepurposes of specification under the aspects of automateddeduction, proving techniques, concurrency and logic,abstract data types and operational semantics, andconstructive methods.

Informatik. Eine einführende Übersicht hat sich als Standardwerk für das Studium der Informatik bewährt. Der vorliegende zweite Teil steht unter dem Leitgedanken "Strukturen", der das Grundthema "Algorithmen" des ersten Teils ergänzt. Zunächst werden Programmstrukturen und Datenstrukturen einschließlich der Techniken ihrer Implementierung behandelt. Sodann werden formale (Sprach-)Systeme, die zur Beschreibung solcher Strukturen dienen, auf relationentheoretischer Grundlage dargestellt. Ein weiteres Kapitel behandelt die Formalisierung der Syntax und der Semantik algorithmischer Sprachen, mit einem Abschnitt über abstrakte Datentypen. Den Abschluß bilden die Anhänge "Korrespondenzen und Funktionen", "Datenendgeräte" und "Zur Geschichte der Informatik" sowie Syntaxdiagramme für die ALGOL 68- und die PASCAL-Notation, die im Buch verwendet werden.

Die Kryptologie, eine jahrtausendealte "Geheimwissenschaft", gewinnt zusehends praktische Bedeutung für den Schutz von Kommunikationswegen, Datenbanken und Software. Neben ihre Nutzung in rechnergestützten öffentlichen Nachrichtensystemen ("public keys") treten mehr und mehr rechnerinterne Anwendungen, wie Zugriffsberechtigungen und der Quellenschutz von Software. - Der erste Teil des Buches behandelt die Geheimschriften und ihren Gebrauch - die Kryptographie. Dabei wird auch auf das aktuelle Thema "Kryptographie und Grundrechte des Bürgers" eingegangen. Im zweiten Teil wird das Vorgehen zum unbefugten Entziffern einer Geheimschrift - die Kryptanalyse - besprochen, wobei insbesondere Hinweise zur Beurteilung der Verfahrenssicherheit gegeben werden. Mit der vorliegenden dritten Auflage wurde das Werk auf den neuesten Stand gebracht. - Das Buch setzt nur mathematische Grundkenntnisse voraus. Mit einer Fülle spannender, lustiger und bisweilen anzüglicher Geschichten aus der historischen Kryptologie gewürzt, ist es auch für Laien reizvoll zu lesen.

For some years, specification of software and hardwaresystems has been influenced not only by algebraic methodsbut also by new developments in logic. These newdevelopments in logic are partly based on the use ofalgorithmic techniques in deduction and proving methods, butare alsodue to new theoretical advances, to a great extentstimulated by computer science, which have led to new typesof logic and new logical calculi. The new techniques,methods and tools from logic, combined with algebra-basedones, offer very powerful and useful tools for the computerscientist, which may soon become practical for commercialuse, where, in particular, more powerful specification toolsare needed for concurrent and distributed systems.This volume contains papers based on lectures by leadingresearchers which were originally given at an internationalsummer school held in Marktoberdorf in 1991. The papers aimto give a foundation for combining logic and algebra for thepurposes of specification under the aspects of automateddeduction, proving techniques, concurrency and logic,abstract data types and operational semantics, andconstructive methods.

The Marktoberdorf Summer Schools on Informatics were started in 1970, with the intention to convene every second or third year a group of top researchers in computing, devoted to preach their most recent results to an elite of advanced students - young and most promising people - and prepared to stand their questions, criticism and suggestions. The themes of these Advanced Study In­ stitutes under the sponsorship of the NATO Scientific Affairs Division varied slightly over the years, oscillating more or less around Programming Methodo­ logy, as the following list shows: 1970 Data Structures and Computer Systems 1971 Program Structures and Fundamental Concepts of Programming 1973 Structured Programming and Programmed Structures 1975 Language Hierarchies and Interfaces 1978 Program Construction 1981 Theoretical Foundations of Programming Methodology 1984 Control Flow and Data Flow: Concepts of Distributed Programming 1986 Logic of Programming and Calculi of Discrete Design 1988 Constructive Methods in Computing Science 1989 Logic, Algebra, and Computation Logic, Algebra, and Computation is the theme of the summer school to which this volume is devoted. It is the tenth in succession, but it is also the first in a new series (the "blue" series) that is intended to alternate in future with the traditional (the "red" series) arrangement; in fact the tenth summer school in the "red" series with the title "Programming and Mathematical Method" , held in 1990, was the subject of celebrating both its serial number and the twenty years of Marktoberdorf Summer Schools altogether.

The Marktoberdorf Summer Schools on Informatics were started in 1970, with the intention to convene every second or third year a group of top researchers in computing, devoted to preach their most recent results to an elite of advanced students - young and most promising people - and prepared to stand their questions, criticism and suggestions. The themes of these Advanced Study In­ stitutes under the sponsorship of the NATO Scientific Affairs Division varied slightly over the years, oscillating more or less around Programming Methodo­ logy, as the following list shows: 1970 Data Structures and Computer Systems 1971 Program Structures and Fundamental Concepts of Programming 1973 Structured Programming and Programmed Structures 1975 Language Hierarchies and Interfaces 1978 Program Construction 1981 Theoretical Foundations of Programming Methodology 1984 Control Flow and Data Flow: Concepts of Distributed Programming 1986 Logic of Programming and Calculi of Discrete Design 1988 Constructive Methods in Computing Science 1989 Logic, Algebra, and Computation Logic, Algebra, and Computation is the theme of the summer school to which this volume is devoted. It is the tenth in succession, but it is also the first in a new series (the "blue" series) that is intended to alternate in future with the traditional (the "red" series) arrangement; in fact the tenth summer school in the "red" series with the title "Programming and Mathematical Method" , held in 1990, was the subject of celebrating both its serial number and the twenty years of Marktoberdorf Summer Schools altogether.

Die Kryptologie, eine jahrtausendealte "Geheimwissenschaft", gewinnt für den Informatiker zusehends praktische Bedeutung in Verbindung mit Datenbanken und Telekommunikation. Neben ihre Nutzung in rechnergestützten öffentlichen Nachrichtensystemen ("öffentliche Schlüssel") treten interne Anwendungen, die sich auch auf Zugriffsberechtigungen und den Quellenschutz von Software erstrecken. Der erste Teil des Buches handelt in elf Kapiteln von den Geheimschriften und ihrem Gebrauch - von der Kryptographie. Im zweiten Teil wird in elf weiteren Kapiteln das Vorgehen zum unbefugten Entziffern einer Geheimschrift - die Kryptanalyse - besprochen, wobei sich insbesondere Hinweise für die Verfahrensbeurteilung ergeben. Das Buch setzt nur elementare mathematische Kenntnisse voraus. Mit einer Fülle spannender, lustiger und bisweilen anzüglicher Geschichten aus der historischen Kryptologie gewürzt, ist es selbst für den Laien reizvoll zu lesen.

Dieses Buch über elementare Aussagenlogik (wie auch seine geplante Fortsetzung über Elementare Prädikatenlogik und Universelle Algebra) ist aus Vorlesungen an der Technischen Universität München entstanden. Es basiert auf der Überzeugung, daß für Studierende der Informatik nicht nur ein anderer Aufbau des mathematischen Grundstudiums geboten ist als etwa für Ingenieure oder Physiker, sondern auch ein anderes Menü, als es sich an unseren Universitäten nach den GAMM-NTG-Empfehlungen der siebziger Jahre eingebürgert hat. Neben den unentbehrlichen Einführungsvorlesungen in Mathematik sind für die Informatiker vor dem Vordiplom handwerkliche Grundkenntnisse in Logik und Universeller Algebra erforderlich - als Grundlage für die Praktische und die Theoretische Informatik im zweiten Studienabschnitt. Im Gegensatz zu vielen anderen Büchern über Logik ist dieses für den Anfänger der Informatik geschrieben und didaktisch auf sein Niveau eingestellt. Dabei sind sonst eher außerhalb der Aussagenlogik liegende Gegenstände wie die Schaltlogik systematisch einbezogen worden, wo immer es möglich war: von dem für die Programmiersprachen so wichtigen Gebiet der dyadischen Fallunterscheidungen über die Resolventenmethode, die den Anschluß an die Prädikatenlogik vorbereitet, bis zu modalen Aussagenlogiken. Die eingestreuten Übungsaufgaben greifen häufig Gedanken auf, die im Text nur nebenbei erwähnt sind, und stellen Querbezüge her. Die Lösungshinweise am Ende des Buches bieten manche Überraschungen.

Automatic computing has undergone drastic changes since the pioneering days of the early Fifties, one of the most obvious being that today the majority of computer programs are no longer written in machine code but in some programming language like FORTRAN or ALGOL. However, as desirable as the time-saving achieved in this way may be, still a high proportion of the preparatory work must be attributed to activities such as error estimates, stability investigations and the like, and for these no programming aid whatsoever can be of help. In this respect, ALGOL, as an internationally standardized notation which avoids computer-oriented concepts, provides another advantage, not often mentioned, but one which was already the guiding principle at the very beginning of the programming language venture: indeed, a correct ALGOL program is the abstractum of a computing process for which the necessary analyses have already been performed. It is the very purpose of this Handbook to establish such abstract formulations of certain computing processes. Therefore, numerical methods given in this Hand­ book in the form of ALGOL procedures may be put to immediate use wherever ALGOL is known and understood; in fact, application of such a method reduces to little more than calling the corresponding procedure.

Automatic computing has undergone drastic changes since the pioneering days of the early Fifties, one of the most obvious being that today the majority of computer programs are no longer written in machine code but in some programming language like FORTRAN or ALGOL. However, as desirable as the time-saving achieved in this way may be, still a high proportion of the preparatory work must be attributed to activities such as error estimates, stability investigations and the like, and for these no programming aid whatsoever can be of help. In this respect, ALGOL, as an internationally standardized notation which avoids computer-oriented concepts, provides another advantage, not often mentioned, but one which was already the guiding principle at the very beginning of the programming language venture: indeed, a correct ALGOL program is the abstractum of a computing process for which the necessary analyses have already been performed. It is the very purpose of this Handbook to establish such abstract formulations of certain computing processes. Therefore, numerical methods given in this Hand­ book in the form of ALGOL procedures may be put to immediate use wherever ALGOL is known and understood; in fact, application of such a method reduces to little more than calling the corresponding procedure.

Problem oriented programming languages as they have developed over the last ten years essentially serve two purposes which somewhat crudely can be described by the terms man-man communication and man-machine communication, respectively. As a carrier of information between humans, the problem oriented programming language is designed to express the essence of an algorithm in a way which is un­ ambiguous and concise as well as independent of (and therefore meaning­ ful without any reference to) the changing details of computing machine­ ry. As a carrier of information from man to computer, the language permits the human programmer to express his computational needs in a compact way adapted to the general characteristics of computers, but freed from the burdening details of specific computer facilities. This presupposes the existence of algorithms, or programs, which permit the computer itself to transform efficiently programs written in the problem oriented language into machine programs. Thus the entire computing community profits from the work of the individual programmer. The primary purpose of the Handbook is to present a set of algorithms of broad utility from the domain of numerical mathematics written in the problem oriented language ALGOL 60. Therefore, volumes I a and I b are in a sense supplementary as they serve to introduce this language. Volume I a gives a description of the language proper and of its use for writing correct programs. Thus, volume I a primarily covers the aspect of man-man communication by means of ALGOL 60.

Problem oriented programming languages as they have developed over the last ten years essentially serve two purposes which somewhat crudely can be described by the terms man-man communication and man-machine communication, respectively. As a carrier of information between humans, the problem oriented programming language is designed to express the essence of an algorithm in a way which is un­ ambiguous and concise as well as independent of (and therefore meaning­ ful without any reference to) the changing details of computing machine­ ry. As a carrier of information from man to computer, the language permits the human programmer to express his computational needs in a compact way adapted to the general characteristics of computers, but freed from the burdening details of specific computer facilities. This presupposes the existence of algorithms, or programs, which permit the computer itself to transform efficiently programs written in the problem oriented language into machine programs. Thus the entire computing community profits from the work of the individual programmer. The primary purpose of the Handbook is to present a set of algorithms of broad utility from the domain of numerical mathematics written in the problem oriented language ALGOL 60. Therefore, volumes I a and I b are in a sense supplementary as they serve to introduce this language. Volume I a gives a description of the language proper and of its use for writing correct programs. Thus, volume I a primarily covers the aspect of man-man communication by means of ALGOL 60.