Comparing file transfer and encryption performance of Java and.net

Transcription

1 Universiteit Antwerpen (UA) Faculteit Wetenschappen Departement Wiskunde Informatica Academiejaar Comparing file transfer and encryption performance of Java and.net Eindverhandeling ingediend door Bert JAGERS Tot het bekomen van het diploma van Aanvullende Studie informatica en bedrijfswiskunde (ASIB) Zwaartepunt Informatica Promotor: Prof. Dr. S. Demeyer Begeleider: A. Zaidman

2 1 Acknowledgements This year has been a very though but interesting year. Being a Biologist and considering that I only have programmed my first letter of code about a year ago, this year was kind of a giant leap in the dark. I owe the fact that I made it through alive, much more experienced and grown up, to a lot of people. I would like to express my gratitude to them here. First of all, I would like to thank Prof. Dr. Serge Demeyer (UA, LORE) for giving me the chance to complete this thesis and for acquiring an enormous amount of knowledge and a interesting but realistic view to the world of Informatics and Software Engineering by doing so. Second of all I would definitely like to thank Andy Zaidman (UA, LORE) who has guided me through this thesis in a superb way. The fact that he was always there when you needed advice or an answer to a question, and the fact that he did so with a lot of patience, has been a great help to me. Since I couldn t bother Andy the whole time, Sarah Teugels, who has been an enormous help to me, also definitely deserves a special place here. By giving me a lot of practical advice, in a way that I could solve my problem(s), or sometimes by organizing a debugging session together, I came to where I am now. I will always be grateful for the help and the patience she has given me this year and for the knowledge she has passed on to me. I would also like express my gratitude to my fellow students for the help they gave me this year, and especially Wouter Cuypers who has provided me with great advice and interesting points of view that helped me to tackle some of the problems I was experiencing. My family deserves a lot of thanks for the support and understanding they have given me throughout this year. Although I may not always show it, know that I have really appreciated it. A special word of thanks to my parents for 2

3 giving me all the chances and opportunities that made me the person I am today. And last but definitely not least, I would like to thank my fiancée Kristin for putting up with me through this difficult year, for supporting me when things didn t seem to go that well and for enduring the many times I couldn t be there for her due to an awful lot of work for school This thesis is the result of my labor and I will take full responsibility for it. 3

4 2 Samenvatting Met de introductie van Microsoft s.net Framework in 2000, heeft het Java Platform van Sun Microsystems er een geduchte concurrent bij gekregen. Sindsdien beconcurreren zij elkaar voor de leidende positie in de markt van de software ontwikkelingsomgevingen. Beiden bekleden elk tegenwoordig een marktaandeel van om en bij de 35 à 40% waardoor geen van beide geneigd is om spoedig te verdwijnen. Een andere interessante trend is de grote groei, zowel in aantal als in populariteit, van de Peer-to-Peer (P2P) applicaties. Deze trend past perfect in de huidige maatschappij waarin het digitaal verzenden van (gevoelige) data over netwerken steeds grotere proporties aanneemt. P2P applicaties kunnen deze processen zeker vergemakkelijken maar een goed beveiliging van de te versturen data is absoluut onontbeerlijk. De thesis bevat een korte beschrijving van de twee platformen en de twee talen gebruikt voor de programmering van de applicaties, zijnde Java voor het Java Platform en C# voor het.net Framework. Vervolgens worden de twee platformen op basis van verschillende kenmerken met elkaar vergeleken. Dit gebaseerd op de reeds bestaande literatuur. Eén van de twee hoofddoelen van deze thesis is onderzoeken in hoeverre de performantie van de transfer van bestanden via een P2P applicatie verschilt tussen het.net Framework en het Java Platform. Hiervoor werden twee identieke P2P applicatie gecreëerd die in staat waren om via Multicasting over een lokaal netwerk, gebruik makend van het User Datagram Protocol (UDP), in contact te staan met elkaar. Bestanden kunnen vervolgens verstuurd worden via het Transmission Control Protocol (TCP) en dit volledig P2P, zonder dat er een externe Server nodig is. De testen worden vooraf gegaan door een algemene inleiding waarin gekeken wordt wat P2P is en in hoeverre beide platformen hiervoor een ondersteuning bieden. 4

5 Het tweede hoofddoel van deze thesis is het vergelijken van de performantie van de symmetrische encryptie tussen beide platformen. Hiervoor werden twee symmetrische encryptie algoritmen geselecteerd: het TripleDES algoritme en het AES of Rijndael algoritme. In de beide programmeertalen werden er twee applicaties ontwikkeld, één voor elk encryptie algoritme, die in staat waren om een bestand in te lezen en te encrypteren of decrypteren. Vervolgens moesten deze applicaties bestanden van een bepaalde grootte encrypteren en decrypteren. De snelheid waarmee ze dit deden werd genoteerd. Ook hier worden de testen vooraf gegaan door een algemene inleiding omtrent symmetrische encryptie en een korte bespreking van de twee gebruikte algoritmen. De performantie van beide platformen blijkt gelijk te liggen wanneer we de transfer van bestanden via een P2P applicatie in beschouwing nemen. In C# is het echter mogelijk om de snelheid van het sturen en ontvangen van bestanden gevoelig te verhogen door de bestanden ongebufferd te verzenden, gebruik makend van de TcpClient class. Het bufferen van bestanden is echter nodig om interoperabiliteit tussen de Java applicatie en de C# applicatie te kunnen verzekeren. Bufferen heeft als extra voordeel dat de gehele file niet eerst volledig moet worden ingelezen alvorens de applicatie kan beginnen encrypteren/decrypteren. Dit spaart geheugen uit dat dan gebruikt kan worden voor andere applicaties/processen. Wat betreft de performantie van de symmetrische encryptie van beide platformen is het duidelijk dat C# gevoelig sneller encrypteert gebruik makend van het TripleDES algoritme. Het omgekeerde is waar voor het AES algoritme, met uitzondering voor de encryptie van grote bestanden (+/- 100Mb) waarbij de C# applicatie sneller is. Wederom kunnen we in beschouwing nemen dat moderne applicaties eerder geneigd gaan zijn om bestanden stukje per stukje in te lezen (in een stream) waarbij deze stukjes dan geencrypteerd worden vanaf de moment dat ze zijn ingelezen. Dit spaart geheugen en maakt dat het proces van encryptie sneller kan verlopen. Daardoor moeten er dus steeds enkel maar kleine stukjes 5

6 geencrypteerd worden. Voor het encrypteren van kleine bestanden is de performantie van beide platformen echter gelijk. Beide platformen blijken even performant te presteren wat betreft het verzenden en ontvangen van bestanden via een P2P applicatie en wat betreft symmetriche encryptie (met betrekking tot de beschouwde algoritmen). Beiden lijken dus adequaat voor de constructie van veilige, efficiënte P2P applicaties. 6

7 3 Abstract To date, Microsoft s.net Framework and Sun s Java Platform compete for the leading position in the market of software development environments. They try to provide an environment to developers that ensures secure, fast and reliable development. Another important trend is the growing number of Peer-to-Peer applications (P2P) used for the transport of data. This thesis will, after a short comparison of both platforms, try to evaluate the performance of both platforms, taking file transfer through a P2P application and symmetric encryption (the TripleDES algorithm and the AES algorithm) into consideration. This may show which platform can be preferred for the development of reliable, fast and secure P2P applications. 7

8 4 Index 1 Acknowledgements Samenvatting Abstract Index Introduction Java and C#, (not) a world of differences? Overview of this thesis Introducing Java and the Java VM The History of Java The Java Platform The Java Virtual machine The Java programming Language Introducing C# and the.net Framework The History of.net and C# The.NET Framework The C# programming language A first small comparison based on known facts Syntax Virtual machines and portable code Portability Standardization Security The Applications The P2P Application The applications for encryption Using a P2P messenger for performance measurements What is peer-to-peer? An overview Java vs..net How do we measure performance? Results of the P2P performance test

9 10.4 Discussion of the results Using symmetric encryption for performance measurements What is symmetric encryption? An overview The TripleDES algorithm AES or the Rijndael algorithm How do we measure performance? Results of the symmetric encryption test Discussion of the results Conclusions: The performance of Java and.net Which platform/language for P2P applications? Which platform/language for symmetric encryption? Memory management Which platform to choose? The General Conclusion and remarks for the future References...60 Appendix A: A list of used abbreviations...66 Appendix B: The StopWatch class

10 5 Introduction 5.1 Java and C#, (not) a world of differences? Since the introduction of C# and the.net framework in 2000 by Microsoft, Java and its Java Virtual machine, for the first time, experienced a serious competitor. Both platforms grew in popularity over the last few years and both have their own share of followers and opposition, mostly the followers of one platform are against the other, resulting in lots of discussions on why their platform is better. Either way, the enterprise development market share of both platforms lies around 35-40% each. It's fairly obvious that neither of these two platforms is "going away" any time soon. [Neward, 2004]. Therefore it might be interesting to see how performant both of this platforms are. Comparing both platforms on each and every aspect would of course be to much work for just one thesis. It can t be done by one person in one year. Therefore, this thesis will emphasize two aspects of both platforms. The two questions this thesis tries to answer are: Peer to peer (P2P) networking: Which platform has the ability to deliver the most performant file sharing? Which has the fastest multicast broadcasts? Symmetric encryption: Which platform can run a selected symmetric algorithm the fastest? Does this result still apply to another symmetric algorithm? Both questions are very relevant in this context. Looking at the growing number and popularity of P2P applications (like ICQ, Gnutella, Kazaa, ), people need fast and safe applications for the transport of sensitive and secure data. Both Java and.net offer the means for the creation of these applications. It would be very interesting to see which platform can offer the most performant ones. By developing the same P2P application, that is capable of broadcasting over UDP and transfer of encrypted files over TCP in Java and C#, and by doing 10

11 performance tests on both, we will try to give a solid answer to these questions. 5.2 Overview of this thesis This thesis starts by introducing the two languages Java and C#, and their respective platforms: the Java platform and the.net Framework (chapters 6 and 7). After this general introduction we do a first comparison of Java and C# and their platforms (chapter 8). This comparison is based on differences and similarities that are already described in existing literature. Special attention is given to a first comparison regarding security. In chapter 9, the reader will find a short description of the applications created for the performance measuring. Two features will be examined: Peer-to-peer (P2P) networking and symmetric encryption. Chapter 10 starts with a short introduction on P2P networking, followed by a performance test. It ends with a summary of the results of this test. The same is done for Symmetric encryption (chapter 11). In the last chapter, a discussion on the performance of Java and C#/.NET, the reader will find a discussion of the results of chapter 10 and 11. A general conclusion will be drawn and a few remarks for the future will end this last chapter. 11

12 6 Introducing Java and the Java VM 6.1 The History of Java The birth of Java started out as a part of a larger project to develop advanced software for consumer electronics: The Green project. These devices are small, reliable, portable, distributed, real-time embedded systems. But at first, creating a new language wasn't even the point of "the Green Project.". When they started the project, the intention was to use C++, but they encountered a number of problems. Initially these were just compiler technology problems, but as time passed the designers discovered that C++ couldn t respond to the requirements of the systems they were writing software for. These problems were best solved by changing the language [Sun, 95]. Java technology was created as a programming tool in a small, closed-door project initiated by Patrick Naughton, Mike Sheridan, and James Gosling of Sun in Back in the early nineties, the Internet was becoming popular as a way of moving media content -- text, graphics, video -- throughout a network of heterogeneous devices using HTML. Java technology had been designed in parallel to move media content across networks of heterogeneous devices, but it also offered the capability to move "behavior" in the form of applets along with the content. HTML alone could not do that, but it did set the stage for Java technology. This resulted in the HotJava browser around On May 23, 1995, John Gage, director of the Science Office for Sun Microsystems, and Marc Andreessen, cofounder and executive vice president at Netscape, stepped onto a stage and announced to the SunWorld audience that Java technology was real, it was official, and it was going to be incorporated into Netscape Navigator [Byous, 1998]. After this, Java quickly became very popular and to date is being used for the creation of many applications on many different platforms. 12

13 6.2 The Java Platform It is important to understand what is meant by the term platform. To a computer programmer, a platform is defined by the application programming interfaces (APIs) he or she can rely on when writing a program. These APIs are usually defined by the operating system of the target computer. Thus, a programmer writing a program to run under Microsoft Windows must use a different set of APIs than a programmer writing the same program for the Macintosh or for a Unix-based system. In this respect, Windows, Macintosh and Unix are three distinct platforms. Apart from these OS related APIs, Java also contains lists, vectors and lots of other things that cannot be found in most other languages. Fig. 1: The Java 2 Platform SE version 1.4 as described in [Sun, 2004a] The Java platform is just as important as the Java programming language or the virtual machine. All programs written in the Java language rely on the set of predefined classes (Java Class Libraries or JCL) that are included in the Java platform. Java classes are organized into related groups known as 13

14 packages. The Java platform defines packages for functionality such as input/output (I/O), networking, graphics, user-interface (UI) creation, security and much more. Java is not an operating system. Nevertheless, the Java platform provides APIs with a comparable depth to those defined by an operating system. With the Java platform, you can write applications in Java without sacrificing the advanced features available to programmers writing native applications targeted at a particular underlying operating system. An application written on the Java platform runs on any operating system that supports the Java platform. This means you do not have to create distinct Windows, Unix or Macintosh versions of your programs, for example. A single Java program runs on all these operating systems, which explains why Write once, run anywhere is Sun s motto for Java [Flanagan, 2002]. 6.3 The Java Virtual machine The Java Virtual Machine (JVM) or Java interpreter, is the crucial piece of every Java installation. By design, Java programs are portable, but they are only portable to platforms to which the Java interpreter is ported. Sun ships JVM implementations for its own Solaris operating system and for Microsoft Windows and Linux platforms. Many other vendors, including Apple and various commercial Unix vendors, provide Java interpreters for their platforms. The JVM is not only for desktop systems however. It had been ported to set-top boxes, and scaled down versions are even available for hand-held devices that run Windows CE and PalmOS. Since there are so many different target operating systems, it is logical that Java is available in many different forms. Sun alone provides four different Java 2 platforms, all containing a Virtual Machine but different in size, target and possibilities ( java.sun.com): Java 2 Platform, Standard Edition Tools (J2SE): There are two principal products in the J2SE platform family: Java 2 Runtime 14

15 Environment, Standard Edition (JRE) and Java 2 Software Development Kit, Standard Edition (SDK). The JRE provides the Java APIs, Java virtual machine, and other components necessary to run applets and applications written in the Java programming language. The JRE does not contain tools and utilities such as compilers or debuggers for developing applets and applications. The Java 2 SDK is a superset of the JRE, and contains everything that is in the JRE, plus tools such as the compilers and debuggers necessary for developing applets and applications (fig. 1) [Sun, 2004 a]. Java 2 Platform, Enterprise Edition Tools (J2EE): The Java 2 Platform, Enterprise Edition (J2EE) defines the standard for developing multi-tier enterprise applications. It takes advantage of many features of the Java 2 Platform, Standard Edition (J2SE). Building on this base, the Java 2 Platform, Enterprise Edition adds full support for Enterprise JavaBeans components, Java Servlets API, JavaServer Pages and XML technology [Sun, 2004b]. Java 2 Platform, Micro Edition Tools (J2ME): The Java 2 Platform, Micro Edition (J2ME) provides a robust, flexible environment for applications running on consumer devices, such as mobile phones, PDAs, and TV set-top boxes, as well as a broad range of embedded devices. J2ME includes Java virtual machines and a set of standard Java APIs defined through the Java Community Process, by expert groups whose members include leading device manufacturers, software vendors, and service providers [Sun, 2004c]. Java Card Tools: Java Card technology enables smart cards and other devices with very limited memory to run small applications, called applets, that employ Java technology. The technology enables developers to build, test, and deploy applications and services rapidly and securely. This accelerated process reduces development costs, increases product differentiation, and enhances value to customers. In a manner complementary to the Standard, Enterprise, and Mobile editions of the Java 2 Platform, Java Card technology makes it easy to 15

16 integrate security tokens into a complete Java software solution [Sun, 2004d]. As already stated, other vendors have their own JVM and can be considered as competition for Sun on the enterprise level. IBM s WebSphere is an example. It contains its own JVM that is not Sun s. There are also alternatives to Sun s JVM made by the open source community. A good example here is Kaffe ( Although interpreters are not typically considered to be high-performance systems, JVM performance is remarkably good and has been improving steadily. Of particular note is the VM technology called Just-In-Time (JIT) compilation, whereby Java byte codes are converted on-the-fly into nativeplatform machine language, boosting execution speed for code that is run repeatedly [Flanagan, 2002]. The version of the Java HotSpot VM (as shown in fig. 1) builds on a strong foundation of features and capabilities, assuring scalability, performance, reliability, and serviceability (RAS) [Sun, 2002b]. 6.4 The Java programming Language Java is said to be a simple, object-oriented, distributed, interpreted, robust, secure, architecture neutral, portable, high-performance, multi-threaded and dynamic language [Sun95]. Its syntax is similar to that of C. The designers strove to make the Java language powerful, but, at the same time, they tried to avoid the overly complex features that have bogged down other objectoriented languages, such as C++. By keeping the language simple, the designers also tried to achieve that it became easier for programmers to write robust, bug-free code. Some of the key benefits of Java are described next: Write once, run anywhere : For Sun this became the core value proposition of the Java platform. It means that the most important promise of the Java technology is that you only have to write your 16

17 application once for the Java platform and then you ll be able to run it anywhere. That is, anywhere that supports the Java platform. By now, Java support is being integrated in almost any operating system. Security: Both the language and the platform were designed with security in mind. The Java platform allows users to download untrusted code over a network and run it in a secure environment in which it cannot do any harm. Network-centric programming: The Network is the computer. The designers of Java believed in the importance of networking and designed the Java platform to be network-centric. Other features that are posed as key benefits are Internationalization, Performance and programmer efficiency [Flanagan, 2002]. Java is a language that can be used to build robust software: Java is type-safe, meaning that programs are prevented from accessing objects in inappropriate ways. All code and data is associated with a type, all objects have a associated type and only operations defined by the associated type can be performed on an object. Type safety eliminates an entire category of errors in C and C++ programs stemming from invalid casts, bad pointer arithmetic and even malicious code. Java also provides automatic memory management in the form of a high-performance tracing generational garbage collector. This frees programmers from performing manual memory management or reference counting, and eliminates an entire category of errors such as dangling pointers, memory leaks, and circular references. Java also includes features that promote robustness such as for example detection of attempts to use uninitialized variables. 17

18 7 Introducing C# and the.net Framework 7.1 The History of.net and C# Reports of a new language from Microsoft first started Surfacing in At that time, the language was called COOL, and was said to be very similar to Java. In June 2000, Microsoft released the specifications for a new language called C# (pronounced see-sharp ). This was rapidly followed by the release of a preview version of the.net Framework SDK (which included a C# compiler) at the July 2000 Professional Developer s Conference (PDC), in Orlando Florida. The new language was designed by Anders Hejlsberg (creator of Turbo Pascal and architect of Delphi), Scott Wiltamuth, and Peter Golde. With C#, they focused on what was right about existing languages and adding improvements to make something better [Jones, 2001]. Described in the C# Language specification as a simple, modern, object-oriented, and type safe programming language derived from C and C++ [ECMA(a), 2002], C# bears many syntactic similarities to C++ and Java [Drayton et al., 2003]. From July 2000 to January 2002, the.net Framework underwent an extensive public beta that allowed developers to try out the programming environment. This allowed Microsoft to both solicit and react to developer community feedback before finalizing the new platform. From the earliest public previews, core specifications detailing the C# language, the classes in the Framework class library (FCL), and the inner workings of the Common Language Runtime (CLR) have been freely available. In November 2000, began an intense standardization process by submitting the specifications for the C# language, a subset of the FCL, and the runtime environment to ECMA for standardization. Organizations participating in the effort included Microsoft, HP, Intel, IBM, Fujitsu Software, ISE, Plum Hall, Monash University and others. The work was performed under the auspices of ECMA Technical committee TC39. 18

19 After more then a year, the task groups completed their standardization work and presented the specifications to the ECMA General Assembly. In December 2001 the general Assembly ratified the C# and Common Language Interface (CLI) specifications, assigning them the ECMA standard numbers of ECMA-334 (C#) [ECMA(a), 2002] and ECMA-335 (the CLI) [ECMA(b), 2002]. In late December, 2001, ECMA submitted the standards to the International Organization for Standardization (ISO) via the Fast-Track process, and in April 2003, ISO ratified the standards as ISO/IEC (C#) [ISO/IEC(a), 2003] and ISO/IEC (CLI) [ISO/IEC(b), 2003] giving C# and the CLI bona-fide international standard status (see bibliography for the web links of these standards). Of course, for the standard to have an impact there must be implementations. In addition to the commercial.net Framework, Microsoft itself has two other CLI implementations: the Shared Source CLI (SSCLI, but formerly known under the code name Rotor) and the.net Compact Framework. The first is a working implementation of the CLI and C# standards that builds and runs on Windows XP, FreeBSD and Mac OS X (web link: The latter, now available with Visual Studio.NET 2003, is an implementation of the CLI designed to target resource-constrained devices, and is available for Pocket PC and Windows CE 4.1+ operating systems [Drayton et al., 2003]. However, Microsoft s implementations are not the only ones available. Other CLI implementations include the Mono project and dotgnu. The Mono project ( and started by the Ximian Corporation, is aiming to provide an implementation of not only the CLI platform and the C# compiler, but also a larger set of classes selected from Microsoft s.net Framework FCL. In addition to the internal resources, Ximian has committed to the project, the Mono project has also attracted attention from the broader open source community, and appears to be gathering steam [Drayton et al., 2003]. But Mono tries to be much more. Apart from a compiler for the C# language, an ECMA-compatible runtime engine (the Common 19

20 Language Runtime, or CLR), and class libraries (including ADO.NET and ASP.NET), Mono also has its own and third party class libraries. Gtk#, a set of.net bindings for the gtk+ toolkit and assorted GNOME libraries. This library allows you to build fully native Gnome application using Mono and includes support for user interfaces built with the Glade interface builder. Furthermore, Mono's runtime can be embedded into applications for simplified packaging and shipping. In addition, the Mono project offers an IDE, debugger, and documentation browser [Mono Project, 2004]. While not as high-profile as Mono, the dotgnu project ( has also been making headway, and includes some interesting and unique concepts. The core of dotgnu is Portable.NET, which was originally developed by Rhys Wheaterly before merging his project with dotgnu in August There are unique aspects to the dotgnu project, including the fact that it was originally designed around a CIL (Common Intermediate Language) interpreter rather then a JIT (Just-In-Time) compiler, and the developers plan to support directly executing Java binaries [Drayton et al., 2003]. 7.2 The.NET Framework The Microsoft.NET Framework consists of two important elements: a runtime environment called Common Language Runtime (CLR), and a class library called the Framework Class Library (FCL). The FCL is build on top of the CLR and provides services needed by modern applications (figure 2). 20

21 Fig 2 : the.net Framework While applications targeting the.net Framework interact directly with the FCL, the CLR serves as the underlying engine. The CLR is a modern runtime environment that manages the execution of user code, providing services such as JIT (just-in-time) compilation, memory management, exception management, debugging and profiling support, and integrated security and permission management. Ultimately, the CLR exists to safely execute managed code, regardless of the source language. In order to provide cross-language integration (one of the goals of the.net Framework), the CLR needs intimate knowledge of the managed code that it is executing. To meet this requirement, the CLR defines a shared type system called the Common Type System (CTS). The CTS defines the rules by which all types are declared, defined and managed, regardless of the source language. The CTS is designed to be rich and flexible enough to support a wide variety of source languages, and is the basis for cross-language integration, type safety, and managed execution services. Since not all languages support the exact same set of constructs, this can be a barrier to cross-language integration. The solution to this problem is the 21