This paper examines the use of distributed computing based on web services with application to floating license management. The main goal is to automate the processes pertaining to the management activities and ensure at the same time that the security and flexibility requirements are met. We present the challenges posed by these requirements, propose a design and some implementation aspects using the latest .NET development platform

Doloca, Adrian

Ţănculescu, Oana

Å¢ănculescu, Oana

Agora University Editing House: Journals

Int. J. of Computers, Communications & Control, ISSN 1841-9836, E-ISSN 1841-9844Vol. VI (2011), No. 4 (December), pp. 615-621Floating License Management - Automation Using WebTechnologiesA. Doloca, O. ŢănculescuAdrian DolocaGr.T. Popa University of Medicine and Pharmacy,Department of Mathematics and InformaticsRomania, Universităţii 16, 700115 IaşiE-mail: ad@umﬁasi.roOana ŢănculescuGr.T. Popa University of Medicine and Pharmacy,Department of Fixed ProsthodonticsRomania, Universităţii 16, 700115 IaşiE-mail: otanculescu@eprpru.umﬁasi.roAbstract: This paper examines the use of distributed computing based onweb services with application to ﬂoating license management. The main goal isto automate the processes pertaining to the management activities and ensureat the same time that the security and ﬂexibility requirements are met. Wepresent the challenges posed by these requirements, propose a design and someimplementation aspects using the latest .NET development platform.Keywords: ﬂoating license management, distributed system, web service,multithreading, .NET development.1 IntroductionSoftware is a vital component of today’s businesses. The fast development of the softwareindustry has produced applications for automating virtually every task, thus saving time andﬁnances. At the same time protecting software from unauthorized usage became a strong ne-cessity. Except the public domain that contains material not owned or controlled by anyone,all other software products are subject to the copyright law which gives the author of an orig-inal work exclusive right regarding its distribution, publication and modiﬁcation. The softwarelicense is for that matter a legal instrument governing the usage and redistribution of softwareapplications protected by copyright, but at the same time a technical means which will preventthe application from running when no authorization is available. This allows a better control ofthe product’s distribution and ensures that illegal use will be kept to a minimum allowing theproducer to economically beneﬁt from the investment and to prevent revenue loss [1].Concerning the method of protection, two main categories of software licensing systems aremost popular: node-locked and ﬂoating licenses. Other license types and a method of optimiza-tion are presented in [2].Node-locked licenses allow an application to be used on only one machine. This is achievedby making the license machine dependant. Therefore the license will include some unique IDs ofhardware components like hard drives, CPU ID, network card ID, which will be checked as partof the license veriﬁcation process.Floating licenses (roaming licenses) allow multiple users to share access to a softwareproduct. Usually the number of users simultaneously running the application is limited, thislimit being embedded in the license itself. This provides a higher degree of ﬂexibility since usersare not restricted to using the application from a designated workstation. The software can beCopyright c 2006-2011 by CCC Publications616 A. Doloca, O. Ţănculescuinstalled on any number of client computers but if the limit is reached a new user whishing tostart it is put on hold and will be able to start its session as soon as an existing session is ﬁnished.FlexNet and the older version FlexLM [3] are the de facto standards in electronic licensingbeing a partner of major software producing companies. These products support a large varietyof license management scenarios focusing at maintaining a high degree of ﬂexibility in choosingfeature and pricing conﬁgurations. Using FlexNet software producers can generate, transfer andactivate licenses and can also protect their products against piracy. [4] and [5] deliver an insightinto the challenges that ﬂoating license management poses and shows how FlexLM ﬁnds solutionsto these challenges.This paper presents an original software system that provides ﬂexibility in the managementof ﬂoating licenses in enterprise environments, attaining a high degree of automation by usingthe latest Internet development technologies. It also discusses details of implementation andbeneﬁts of this system. The presentation is structured as follows. Chapter 2 looks into thefeatures that an advanced ﬂoating license management system is required to have. Chapter 3shows the structural aspects and communication between system components. Security issuesgenerated by exchanging information over public networks are addressed in chapter 4. Someimplementation aspects and recommendations can be found in chapter 5. Final conclusions arepresented in chapter 6.2 System Features and FunctionsThe ﬂoating license management system should have at least some features to ensure thatthe terms of the license contract are enforced and that this is done in a secure manner, withminimum eﬀort by automating the necessary tasks. Below we present these features in detail.A. Limit the number of simultaneously running application instances accordingto the license contractAt startup the application will connect to the license server in order to check if it has theauthorization to run. If the maximum number of running instances has already been reached,the requesting application is denied the right to start and will close. When an ongoing workingsession is ﬁnished, the corresponding seat on the license server is freed and another applicationcan start. Of course, some requirements exist for this feature:- the license information must be centralized on a license server;- the license server must be accessible in a network by all client computers which have theapplication installed.B. Ensure security of the license content and prevent fraud attemptsThe license content resides on the license server usually in the form of a text or a binaryﬁle which contains information pertaining to the company that acquired the license and themaximum number of simultaneously running application instances. In the proposed system thefollowing set of parameters are used:a) License-ID : uniquely identiﬁes the license in the license database residing at the producerof the software. It contains a random number and possibly the creation date and time.This will block, for example, any attempt to use older licenses that have been issued to thesame company, for the same software.b) Company-ID : short identiﬁer of the company that purchased this license. It prevents licenseusage across companies by simply copying the license content.Floating License Management - Automation Using Web Technologies 617c) Application-ID : identiﬁes the application the license refers to. Diﬀerent software can usethe same license management system by using diﬀerent Application-IDs. It prevents illegaluse of licenses issued for other software.d) Conﬁguration-ID : this piece of information speciﬁes the conﬁguration/version of the soft-ware which will be running (demo version, full version, light version, professional version,enterprise version, etc.). It ensures that only the authorized version of the software will beused.e) Hardware-ID : uses one or a combination of multiple serial numbers of certain hardwarepieces to ensure that the license is used only on a certain machine that was authorizedfor license management purposes. The most popular hardware related serials are: thehard drive ID (volume serial number), network card physical address (MAC), CPU ID.This prevents installing the license on several machines and using them simultaneously forincreasing the number of running software instances over the authorized limit.f) MNRI (Maximum number of simultaneously running application instances): speciﬁes howmany instances of the software can run at the same time on client computers that use thelicense server. If this limit is reached, additional instances are prevented from running untilan existing session is terminated.The above listed information is combined into a unique string – the license content, which isencrypted using a strong encryption algorithm and stored in the license ﬁle. The encryptionprotects the license from any attempts to adjust the contained parameters for using it in otherenvironments than the one it was issued for.C. Provide ﬂexibility for license conﬁguration and installationFor maximum conﬁguration and installation ﬂexibility the license ﬁle will be regularly syn-chronized with a remote server controlled by the software producer. The ﬁrst time the licenseserver is started it will contact the remote server for the ﬁrst synchronization. As a result, thelicense ﬁle is created and subsequently used until the next synchronization takes place. Duringeach license synchronization, any modiﬁcations in the license parameters on the remote serverare automatically transmitted to the license server. In this way no manual updating process ofthe license is required. This process is depicted in ﬁgure 1, in chapter 3. The synchronizationensures that the license used by the client is up-to-date and it hasn’t been tampered with. Atthe same time all contract amendments that are made at one time are quickly and automaticallyimplemented on the client’s server.D. Provide ﬂexibility of working with multiple application types and multipleconﬁgurations of a software productDue to the Application-ID and Conﬁguration-ID parameters the license is linked to a speciﬁcsoftware product and a version/conﬁguration. The same license structure can be used with othersoftware products just by adapting these two parameters accordingly. On the client side, onelicense server will be able to handle multiple licenses for multiple applications and conﬁgurations.E. Oﬀer ﬂexible administrative functions for the client company as well as forthe producer of the softwareRegarding the used licenses, the client company is able to perform the following tasks:- install license during the ﬁrst synchronization;618 A. Doloca, O. Ţănculescu- update license information during subsequent synchronizations;- monitor and manage active users and licenses;- conﬁgure intranet and internet network settings, etc.The software producer has also an administration tool that enables them to:- create new licenses according to speciﬁcations given in section B of this chapter;- modify existing licenses (upgrade or downgrade);- monitor the synchronization state of each client;- block or activate a license, etc.3 System ArchitectureThe architecture of the ﬂoating license management system is based on a distributed structure(ﬁgure 1) comprising three major components:1) Client workstations running the licensed software;2) In-house license server which authorizes software utilization on client workstations onone hand, and performs license synchronization with the remote server on the other hand;3) Remote License Server controlled by the software producer, hosts the license databaseand performs automatically synchronizations over the Internet with the clients, acting asa web service.The distributed structure using an in-house license server and a remote license server ensurescentralized administration of the licenses both at the client and at the software manufacturer.Also the license installation and update are done automatically with a minimum of interventionfrom human operators. This accomplishes two main goals: ease of administration and securityof the license content. Other advantages include use of public networks (Internet) and ﬂexibilityin case of software upgrade [6].The client computer sends a message to the in-house license server during startup requestingauthorization for software utilization. At the server, a service (e.g. Windows service) receivesthe message and based on the content of the license residing in the license ﬁle and on the currentnumber of running application instances sends back a response message authorizing or denyingsoftware utilization. Using a web service client, the license server checks periodically with theremote license server if there are any modiﬁcations and, if necessary it updates the license ﬁle.If this communication fails, then a warning is issued on the in-house license server but thefunctionality is not aﬀected. Checking with the remote license server is attempted again and if itfails repeatedly, after a speciﬁc amount of time, the license on the in-house license server expires,which results in blocking all software utilization on client workstations. Normal functionality isresumed after a successful communication between the in-house and the remote license servers.This mechanism ensures that the license is up-to-date at all times and that fraud attempts areavoided.Floating License Management - Automation Using Web Technologies 619  Internet ....... Client computer 1 Client computer 2 Client computer n In-house License Server (Client Side)  License Service License File Client for  License Web Service License Manager Remote License Server (Software Producer Side) License  Database License Web Service License Manager Desktop App. Web App. Client Workstations (with licensed software) SSL channel SSL channel License synchronization Application authorization Figure 1: Floating License Management System Architecture620 A. Doloca, O. Ţănculescu4 Security issuesBeing a system that relies on exchanging information over public computer networks andalso working with private information (i.e. the license content) in an environment that is notcontrolled by the software manufacturer, security has an important role. There are two aspectsof this problem: securing the data transfer during the synchronization process and protectingthe license content.An eﬀective method for dealing with the ﬁrst aspect is to create an encrypted communicationchannel using Secure Socket Layer Connections (SSL). Thus, not only the data sent to the remotelicense server but also the license content received back, are protected from possible outsideattacks. The subject of using SSL for Windows web services is covered in [7].The information contained by the license ﬁle (see chapter 2, section B) must also be protectedas it contains sensitive information established by the license contract. Because the informationis combined into a unique string, this can be encrypted using an advanced encryption algorithmlike Rijndael [8] and stored as a string representation in the license ﬁle. The license service willread and decrypt internally this information at startup.5 Implementation aspectsThe overview architecture of the license server is presented in ﬁgure 2. As the applicationhas to be able to communicate at all times, it was implemented as a Windows service whichworks in the background and spawns two additional execution threads. One is the TCP PortListener thread which receives all the requests from the local network for application start-upauthorization and keeps track of the machines and active users that use the licenses. The otherthread is responsible for synchronizing the license ﬁle content with the remote license server.This structure allows timely responses through both communication channels by keeping thetwo activities as independent as possible. License File Settings File  License Service Worker Object Thread 1 TCP Listener Thread 2 License Synchronizer Internet User list TCP Port Figure 2: License Server Implementation StructureWe chose for implementation the Microsoft .NET Framework platform using the Visual Studio.NET 2008 development environment. Among the reasons:Floating License Management - Automation Using Web Technologies 621- development support for a wide range of technologies like Web service, Windows service,Web applications and desktop applications;- support for programming of TCP Ports;- very good documentation.6 ConclusionsThis paper discusses the aspects of ﬂoating license management and proposes a speciﬁcsystem architecture that meets the ﬂexibility requirements and oﬀers at the same time, a highdegree of automation for most of the license management activities. Using the Web servicetechnology, license installation, activation and synchronization can be performed automaticallyby the system. Details of implementation using the latest .NET development framework arepresented.Bibliography[1] R. Addy, Software License Management, Eﬀective IT Service Management, pp.263-273,Springer Berlin Heidelberg, 2007.[2] D. Gull, A. Wehrmann, Optimized Software Licensing – Combining License Types in a LicensePortfolio, Gabler Verlag, Vol.1, N0.4, pp. 277-288, August, 2009.[3] FlexNet Producer Suite for Software Vendors, http://www.ﬂexerasoftware.com/products/ﬂexnet-producer-suite-software-vendors.htm.[4] S. Sultan, Floating License Management – A Review of FlexLM, http://wob.iai.uni-bonn.de/Wob/images/36311141.pdf.[5] FLEXlm End Users Guide, http://web.njit.edu/topics/Prog_Lang_Docs/html/ﬂexlm/all.htm.[6] H. Wang et al ,Web services: problems and future directions, Web Semantics: Science,Services and Agents on the World Wide Web, Vol.1, Issue 3, pp. 309-320, Elsevier, April2004.[7] HOW TO: Secure XML Web Services with Secure Socket Layer in Windows 2000,http://support.microsoft.com/kb/307267.[8] Advanced Encryption Standard, http://en.wikipedia.org/wiki/Advanced_Encryption_Standard.

Floating License Management - Automation Using Web Technologies

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Floating License Management - Automation Using Web Technologies

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