Abstract:
A data processing system for accessing a host computer. A smart card is detected at the data processing system, which in turn queries the smart card for an indication of a location of user information. A secure channel is established with the location of user information. User information is retrieved associated with the smart card from the location. A connection is established to the host computer with the user information. Key to this invention is the ability to use this infrastructure for authentication when a smart card cannot be used at the data processing system.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates generally to an improved distributed data processing system and in particular to a method and apparatus for client authentication and/or application configuration. Still more particularly, the present invention provides a method and apparatus for client authentication and/or application configuration using smart cards. 
     2. Description of Related Art 
     Security is a significant issue in the computing industry. Most computer systems employ user identification and a password for verification of a user prior to allowing the user to access data within a computer while maintaining a secure environment for computing. With client authentication, the issue is validating that a particular client is who the client says that it is. Once a client is authenticated, then the identity also may be used to access various resources, such as applications or databases. Beyond access control, personalized configuration or personal defaults for a user is another issue of interest. Personalized configuration or personal defaults involves being able to tailor computer system behavior based on client identity. 
     Up to now, schemes involving using a smart card for identity assumed that all access to a system would be made using the smart card and did not address the equally important issue of personalized configuration. One problem is that a given system user may be mobile and that the user may find, on occasion, a need to use a different computer system other than the normally assigned computer system. 
     Whilst smart card technology has evolved rapidly, significant limitations still exist as to the storage available on such a card. A smart card is typically a credit card sized device containing an embedded processor that stores information. Smart cards are typically used in computer security for authentication of users to various computer systems. The industry preferred technology for secure access today is based on public key algorithms using standard based certificates and encodings. Because of this, in conjunction with the need to represent roles and allow distributed rather than centralized administration of certificates, the size of an end user&#39;s Public Key Infrastructure (PKI) key-ring often will exceed the storage capacity of even the largest smart card. 
     Historically, before PKI exploitation, a typical user may have several identifiers and passwords for which the user is responsible. For example, a user might have one user identification and password to gain access to the user&#39;s workstation, another user identification and password to gain access to a terminal emulator, another user identification and password to gain access to electronic mail, and yet additional different identifications and passwords used to access different applications. In many instances, these passwords are set to expire after certain dates to improve security, which means that each of the passwords will have rules for creating the password (such as five alpha numeric characters with the second character being numeric) and set expiration dates (such as 30 days, 45 days, or 60 days). The configuration of computer networking becomes unmanageable quickly because it is extremely difficult to keep all passwords and user identifications synchronized. As a result, many users resort to writing their user identifications and passwords on a piece of paper, somewhat eliminating the security benefit intended by the passwords. Even personal users of a computer network may be faced with an excess of user identification and password requirements, such as a user identification and password for their Internet provider, one for electronic mail, another for various bulletin boards which a user may subscribe to. 
     A need has arisen for single sign-on products. These products are becoming available on the market place today. Many of these products keep a list of all the identifications and maps the user from one “single” sign-on to the appropriate user identification/password pair for their destination. As a result, the user identification/password changes in the data stream transparently to the user. This approach, however, requires significant administrative effort to prime the database with the correct user/password pairs and require synchronization of password databases as passwords change or expire. 
     Therefore, it would be advantageous to have an improved method and apparatus for allowing client authentication to various servers and to allow access to configuration information for various software applications at whatever client computer a user may access. 
     SUMMARY OF THE INVENTION 
     The system and associated method provides for a method in a data processing system for accessing a target computer. A smart card is detected at the data processing system, which in turn queries the smart card for an indication of a location of user information. This target computer may be, for example, a host computer or another server in an Internet Protocol network. A secure channel is established with the location of user information. User information is retrieved associated with the smart card from the location. A connection is established to the target computer with the user information. Key to this invention is the ability to use this infrastructure for authentication when a smart card can not be used at the data processing system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a pictorial representation of a distributed data processing system in which the present invention may be implemented; 
     FIG. 2 is a block diagram of a data processing system, which may be implemented as a server; 
     FIG. 3 is a block diagram of a data processing system in which the present invention may be implemented; 
     FIG. 4 is a diagram of a smart card in accordance with a preferred embodiment of the present invention; 
     FIG. 5 is an illustration of a process used to retrieve a user&#39;s key-ring in accordance with a preferred embodiment of the present invention; 
     FIG. 6 is an example of a user&#39;s entry in the directory in accordance with a preferred embodiment of the present invention; 
     FIG. 7 is a diagram of a process for accessing a host in accordance with a preferred embodiment of the present invention; 
     FIG. 8 is a flowchart of a process for retrieving a key ring and user configuration information in accordance with a preferred embodiment of the present invention; 
     FIG. 9 is a flowchart of a process used by a server to provide access to a key-ring and user configuration information in accordance with a preferred embodiment of the present invention; and 
     FIG. 10 is a flowchart of authentication of a user at a host on a SNA network in accordance with a preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference now to the figures, and in particular with reference to FIG. 1, a pictorial representation of a distributed data processing system in which the present invention may be implemented is depicted. Distributed data processing system  100  is a network of computers in which the present invention may be implemented. Distributed data processing system  100  contains an Internet Protocol (IP) network  102  and a systems network architecture (SNA) network  104 , which is the medium used to provide communications between various devices and computers connected together within distributed data processing system  100 . IP network  102  and SNA network  104  may include permanent connections, such as wire or fiber optic cables, or temperate connections made through telephone connections. 
     In the depicted example, clients  104  and  106  are connected to IP network  102 . In addition, server  108  and server  110  are connected to IP network  102 . Server  110  provides a connection between IP network  102  and SNA network  104 . A host server  112  is connected to SNA network  104 . Client  104  and client  106  may be clients of various servers, such as server  108 , server  110 , or host server  112 . Clients  104  and  106  may be, for example, personal computers, workstations, or network computers. For the purposes of this application, a network computer is any computer, coupled to a network, which receives a program or other application from another computer coupled to the network. In the depicted example, host server  112  may provide data, such as boot files, operating system images, and applications to clients  104  and  106 . This information also may be provided through server  108  or server  110  depending on the configuration of distributed data processing system  100 . Distributed data processing system  100  may include additional servers, clients, networks, and other devices not shown. 
     In the depicted example, IP network  102  is the Internet, representing a worldwide collection of networks and gateways that use the TCP/IP suite of protocols to communicate with one another. At the heart of the Internet in this example is a backbone of high-speed data communication lines between major nodes or host computers, consisting of thousands of commercial, government, educational, and other computer systems, that route data and messages. In this example, SNA network  104  contains a logical structure, formats, protocols, and operational sequences for transmitting information units through, and controlling the configuration and operation of, networks. The layered structure of SNA network  104  allows the ultimate origins and destinations of information, that is, the end users to be independent and unaffected by the specific SNA network services and facilities used for information exchange. A number of layers are provided for the end user, which include a transaction services layer, a presentation services layer, a data flow control layer, a transmission control layer, a path control layer, a data link control layer, and a physical control layer. 
     FIG. 1 is intended as an example, and not as an architectural limitation for the processes and apparatus of the present invention. 
     Referring to FIG. 2, a block diagram of a data processing system which may be implemented as a server, such as server  104  in FIG. 1, is depicted in accordance with the present invention. Data processing system  200  may be a symmetric multiprocessor (SMP) system including a plurality of processors  202  and  204  connected to system bus  206 . Alternatively, a single processor system may be employed. Also connected to system bus  206  is memory controller/cache  208 , which provides an interface to local memory  209 . I/O bus bridge  210  is connected to system bus  206  and provides an interface to I/O bus  212 . Memory controller/cache  208  and I/O bus bridge  210  may be integrated as depicted. 
     Peripheral component interconnect (PCI) bus bridge  214  connected to I/O bus  212  provides an interface to PCI local bus  216 . A number of modems  218 - 220  may be connected to PCI bus  216 . Typical PCI bus implementations will support four PCI expansion slots or add-in connectors. Communications links to network computers  108 - 112  in FIG. 1 may be provided through modem  218  and network adapter  220  connected to PCI local bus  216  through add-in boards. 
     Additional PCI bus bridges  222  and  224  provide interfaces for additional PCI buses  226  and  228 , from which additional modems or network adapters may be supported. In this manner, server  200  allows connections to multiple network computers. A memory mapped graphics adapter  230  and hard disk  232  may also be connected to I/O bus  212  as depicted, either directly or indirectly. 
     Those of ordinary skill in the art will appreciate that the hardware depicted in FIG. 2 may vary. For example, other peripheral devices, such as optical disk drives and the like also may be used in addition or in place of the hardware depicted. The depicted example is not meant to imply architectural limitations with respect to the present invention. 
     The data processing system depicted in FIG. 2 may be, for example, an IBM RISC/System  6000  system, a product of International Business Machines Corporation in Armonk, N.Y., running the Advanced Interactive Executive (AIX) operating system. 
     With reference now to FIG. 3, a block diagram of a data processing system in which the present invention may be implemented is illustrated. Data processing system  300  is an example of a client computer. Data processing system  300  employs a peripheral component interconnect (PCI) local bus architecture. Although the depicted example employs a PCI bus, other bus architectures such as Micro Channel and Industry Standard Architecture (ISA) may be used. Processor  302  and main memory  304  are connected to PCI local bus  306  through PCI bridge  308 . PCI bridge  308  also may include an integrated memory controller and cache memory for processor  302 . Additional connections to PCI local bus  306  may be made through direct component interconnection or through add-in boards. In the depicted example, local area network (LAN) adapter  310 , Small Computer System Interface (SCSI) host bus adapter  312 , and expansion bus interface  314  are connected to PCI local bus  306  by direct component connection. In contrast, audio adapter  316 , graphics adapter  318 , and smart card adapter  319  are connected to PCI local bus  306  by add-in boards inserted into expansion slots. Expansion bus interface  314  provides a connection for a keyboard and mouse adapter  320 , modem  322 , and additional memory  324 . SCSI host bus adapter  312  provides a connection for hard disk drive  326 , tape drive  328 , CD-ROM drive  330 , and digital video disc read only memory drive (DVD-ROM)  332  in the depicted example. Typical PCI local bus implementations will support three or four PCI expansion slots or add-in connectors. 
     An operating system runs on processor  302  and is used to coordinate and provide control of various components within data processing system  300  in FIG.  3 . The operating system may be a commercially available operating system such as OS/2, which is available from International Business Machines Corporation. “OS/2” is a trademark of International Business Machines Corporation. An object oriented programming system such as Java may run in conjunction with the operating system and provides calls to the operating system from Java programs or applications executing on data processing system  300 . Instructions for the operating system, the object-oriented operating system, and applications or programs are located on storage devices, such as hard disk drive  326  and may be loaded into main memory  304  for execution by processor  302 . 
     Those of ordinary skill in the art will appreciate that the hardware in FIG. 3 may vary depending on the implementation. For example, other peripheral devices, such as optical disk drives and the like may be used in addition to or in place of the hardware depicted in FIG.  3 . The depicted example is not meant to imply architectural limitations with respect to the present invention. For example, the processes of the present invention may be applied to multiprocessor data processing systems. 
     The present invention provides a method, apparatus, and instructions for allowing a single set of information to be stored on a smart card to enable access to a directory entry on a computer. In the depicted example, the directory entry is contained in an industry standard directory server, which is based on Lightweight Directory Access Protocol (LDAP) or X.500. The eNetwork Directory Server from International Business Machines Corporation, NDS from Novell, and Active Directory from Microsoft are examples of directory servers. This directory entry allows client authentication to a number of servers and access to configuration information for any of a number of software applications. According to the present invention, the information stored on a smart card may be stored on other storage devices, such as, for example, a floppy disk, a hard disk, or a CD-ROM, or be remembered and typed by the user at a prompt. These other storage devices may be used in accessing a server. In this manner, client authentication to servers and access to configuration information may be provided to users who may use different computer systems in which some of these computer systems may not have a smart card reader. 
     With reference now to FIG. 4, a diagram of a smart card is depicted in accordance with a preferred embodiment of the present invention. Smart card  400  in the depicted example is a credit card sized device in which embedded microprocessor  402  is connected to storage  404 , which contains a Personal Identification Number (PIN)  406 , a certificate  408 , and a private key  410 . Embedded processor  402  provides access to certificate  408  and private key  410  only when a correct PIN, matching PIN  406 , is entered. In other embodiments, PIN  406  may not be stored on the card, but is the encryption key to scramble certificate  406  and private key  410 . Alternatively, certificate  408  and private key  410  may be stored on some other type of storage device, such as, for example, a floppy disk, a hard drive, or a CD-ROM encrypted by a PIN. Smart card  400  is used in connection with smart card adapter  319  in FIG. 3 to retrieve certificate  408 , private key  410 , and directory entry name  412 . Certificate  408  and private key  410  are used to create a secure and cryptic communications link to a server to obtain an encrypted key ring from a directory entry, which is identified by directory entry name  412  and is encrypted by key  414 . Of course, other mechanisms may be used to identify the appropriate key ring other than directory entry name  412 . For example, a user name or identification may be employed to obtain access to the key ring for the user. Alternatively, a bind password may be used in place of certificate  408  and private key  410  in creating a secure and cryptic channel to a server for accessing a key ring. In the depicted example, the key ring contains a list of certificates, private keys, and certificate authorities. A certificate is a file that identifies a person or organization and a public key. A bind password is an alternate security control used to provide access to a directory entry. A bind password is analogous to a user&#39;s password. Directory entry name  412  is a directory entry name associated with the user, providing a hint to allow an access device to find the server on which the entry exists. The credentials allowing actual access to the directory entry is ideally a certificate/private key pair, such as certificate  408  and private key  410 . Alternatively, a password may be used. In addition, the key ring normally would be encrypted for protection, which would require the use of an encryption key  414  that would require entry of PIN  406  or another PIN to be entered for actual access to the key ring. In the depicted example, both the credentials and the encryption key are marked in the smart card memory as protected, which requires entering a PIN by the user for access. 
     With reference now to FIG. 5, an illustration of a process used to retrieve a user&#39;s key ring is depicted in accordance with a preferred embodiment of the present invention. The user&#39;s key ring also may contain a list of the user&#39;s private keys in addition to associated certificate and certificate chains. In addition, the user&#39;s key ring also contains a list of certificates of trusted certificate authorities and/or certificate roots. Furthermore, configuration information may be retrieved for the user. A user may decide to gain access to client  500  using smart card  502 . By using smart card  502 , client  500  may initiate an application within applications  504  to prompt the user for a personal identification number to be returned to the smart card in order to gain access to Lightweight Directory Access Protocol (LDAP) server  506  via network  508 . After entry of the personal identification number, smart card information concerning the directory entry name is read from smart card  502  and a connection to LDAP server  506  is created via a secure encrypted channel  510 . This secure encrypted channel is established using the credentials on the smart card, which in the depicted example is a certificate/private key pair. Alternatively, a password may be used to establish the secure encrypted channel. Encrypted key ring  511  for the user is retrieved from user database  512 . In addition, client configuration information for the user may be read from user database  512 . The key ring is decrypted using an encryption key located within smart card  502 . Then, a proper certificate/private key pair for a server, such as a Telnet server, is selected from the key ring. 
     Turning next to FIG. 6, an example of an entry in user database  512  from FIG. 5 is depicted in accordance with a preferred embodiment of the present invention. Entry  600  is a user entry containing typical information for a user, such as telephone numbers, addresses in  602 . In addition, section  604  contains an encrypted copy of the user&#39;s key ring. A list of certificates is found in section  606  of entry  600 . Section  606  also may contain in addition to or in place of a list of certificates, certificate routes. Personalized configuration information is stored in section  608 , which may identify various applications and settings for those applications with which a user interacts. Each of these sections may contain the necessary information or pointers to the necessary information for a particular user. Entry  600  is indexed through directory entry name in section  610 . This directory entry name is the same directory entry name located on a smart card in the depicted example. 
     With reference now to FIG. 7, a diagram of a process for accessing a host is depicted in accordance with a preferred embodiment of the present invention. This example illustrates a user accessing a host after obtaining a key ring from a server. In the depicted example, a three-tier example is shown in which a user accesses the SNA network through an IP/SNA gateway. A user at remote system  700 , using key ring  701 , accesses a secure host application, such as, for example, Time Sharing Option (TSO)  702  or Custom Information Control System (CICS)  704  by a request from remote system  700 , through an IP network  706  to a gateway server system  708 . Path  710  through IP network  706  is a path that information takes in traveling from the user at remote system  700  to gateway server system  708 . Path  710 , in the depicted example, uses a secure socket layer (SSL), which provides encryption and public key authentication. This mechanism allows information sent across channel  710  to be secured from tampering or tracing by unauthorized users. 
     At gateway server system  708 , the application managing communication in the depicted example is a Telnet (TN) server application  712 . This application creates a security packet  714 , which in the depicted example is an encrypted security packet containing a certificate, a token, a token signature, and the certificate chain of the signer. More information on encrypted security may be found in Certificate Based Security in SNA Data Flows, Ser. No. 09/064,632, filed Apr. 22, 1998, attorney docket CR9-98-033. In this example, the signature may be created using the end user&#39;s private key. The token within the packet includes one of the end user&#39;s X.509 personal certificate from certificates  606  in FIG. 6, a time/date stamp, plus the SNA session identification on which the packet will be transmitted. 
     Incorporating the SNA session identification into the packet ensures that the person monitoring or tracing the communication could not reuse the packet to gain access to the information. If an intruder attempted to reuse the security packet, the session identification would not be correct and the access attempt would fail. The time/date stamp further limits the use of the packet and provides additional audit information should the administrator choose to log connection events. Token signature in the depicted example is an X.509 signature algorithm type code, which may be for example, RSA+MD5, RSA+SHA, or TSS, known in the art. 
     The information may be sent through web browser  716  to web server  718 . In turn, web server  718  provides the request to TN server  712 , which creates security packet  714 . Security packet  714  is sent through SNA network  720  through SNA stack  722 . SNA stack  722  contains the various layers needed to transfer information to SNA network  720 . From SNA network  720 , host computer  723  receives the information at virtual telecommunications access method (VTAM)  724 . VTAM  724  contains a set of programs that maintain control of the communication between terminals and the application programs running under different host operating systems. VTAM  724  verifies the signature and verifies that the session identification encrypted with the token is the same session identification from which the token came. 
     Upon a successful verification, VTAM  724  passes information, such as certificate to resource access control facility (RACF)  726  for verification. If RACF  726  determines that the packet signer was a trusted delegate, then RACF  726  knows that the user certificate was validated at the mid tier (SSL in this example) and then the user is allowed to access secure applications, such as TSO  702  or CICS  704 . If RACF  726  determines that the certificate is not from a trusted party, then the session is rejected. 
     In addition, after determining that the certificate is from a trusted party, personalized or configuration defaults for these various applications may be applied for the particular user at client  700 . Various applications may be downloaded to client  700 , such as, for example, distributed applications  728 . The types of applications that may be downloaded can be configured based on user configuration information sent up to host computer  722 . Although the depicted example involves a three tier access to the host computer, this portion of the invention could also be applied to a two tier access in which the client is directly connected to a SNA network, rather than using a gateway to the SNA network. 
     Turning now to FIG. 8, a flowchart of a process for retrieving a key ring and user configuration information is depicted in accordance with a preferred embodiment of the present invention. This process is implemented in a client computer for accessing key ring and configuration information for a user in response to the user accessing the client with a smart card. The process begins by detecting the start of an access window, such as a host on demand (HOD) window (step  800 ). Next, a determination is made as to whether a smart card or other access device containing the appropriate data structures is present (step  801 ). If a smart card or other access device containing the appropriate data structures is present, the user is prompted to enter a PIN that will be used to access data within the smart card (step  802 ). The smart card is then accessed (step  804 ). In accessing a smart card, data such as the necessary information to access the appropriate server for the user key ring and configuration information is retrieved from the smart card. 
     A determination is then made as to whether the access to a smart card was successful (step  806 ). This step determines whether the personal identification number was correctly entered or whether an error or defect is present on the smart card. If the access was not successful, an error is returned (step  808 ) with the process terminating thereafter. Otherwise, a connection is created to the server containing the user&#39;s key ring and the configuration information (step  810 ). 
     With reference again to step  801 , if a smart card is not present, the user is prompted for a distinguished name (DN), a DN password, and a key ring PIN (step  811 ) with the process proceeding to step  810  as described above. In step  810 , the server is selected based on the information in the smart card. After the connection has been created, the server is accessed to retrieve the user information (step  812 ). This user information in the depicted example includes the key ring and personal configuration information for the user. A determination is made as to whether the access to the server was successful (step  814 ). If the access was not successful, an error is returned (step  816 ) with the process terminating thereafter. On the other hand, if the access to the server was successful, the key ring is decrypted using an encryption key located on the smart card or a key ring PIN (step  818 ). Then, a server, such as a Telnet server, is selected from the configuration information. The Telnet server may be selected by user input or by configuration information read from the server containing the user&#39;s key ring and personal configuration information (step  820 ). The appropriate certificate/private key pair is selected for the selected Telnet server (step  822 ). Next, a connection is created to the Telnet server (step  824 ) with the process terminating thereafter. The actual connection to the Telnet server and access to the host on the SNA network will be described in more detail below. 
     Turning now to FIG. 9, a flowchart of a process used by a server to provide access to a key ring and user configuration information is depicted in accordance with a preferred embodiment of the present invention. The process begins by receiving the directory entry name and certificate located on the smart card used by the user at the client computer (step  900 ). A determination is made as to whether the user is validated (step  902 ). This validation is made using known processes utilizing the certificate. In addition, part of the validation also is made by determining whether the directory entry name is present on the server. If the user is not validated, the bind is rejected (step  904 ) with the process terminating thereafter. Otherwise, the user&#39;s connection is accepted and a response is made through the communications channel, which in the depicted example is a secure SSL socket (step  906 ). Thereafter, the key ring and configuration information is sent to the user (step  908 ). This information is retrieved from the directory entry associated with the user, which was sent to the server from the smart card. 
     With reference now to FIG. 10, a flowchart of authentication of a user at a host on a SNA network is depicted in accordance with a preferred embodiment of the present invention. This process is employed after the certificate and private key has been retrieved from the key ring on the LDAP server. The process begins by receiving a request for a Secure Socket Layer/Transport Layer Security (SSL/TLS) mutual authentication to be used in building a TN session with the communication server (step  1000 ). Once the SSL/TLS process succeeds in establishing a channel to the communications server, the user&#39;s certificate is available to the intermediate server and the server can trust the value located within the certificate. The server then uses the user&#39;s certificate and creates a security packet for the SNA session between itself and the host on the SNA network (step  1002 ). In doing so, the intermediate server is assuring the host that the user certificate was derived from an SSL/TLS channel whose server side library used a signer&#39;s key ring. In addition, this is assuring the host that the signer&#39;s key ring contains only certificate authorities, which the host trusts. This means that the delegation of authentication responsibility to the communications server is represented by the configured content of the signer&#39;s key-ring and the assurance that the server software will use information via SSL/TLS to validate the user&#39;s certificate submission. The host receives the security packet (step  1004 ). A verification is performed by checking the session ID to ensure that the session ID included in the token matches the session on which the packet arrived (step  1006 ). If the verification fails, access is terminated (step  1008 ). If the session IDs match, then a determination is made as to whether the token signature is valid (step  1010 ). This check is made using an algorithm indicated to verify that the token has not been tampered with. Methods for determining tampering are known in the art and not unique or pertinent to the present invention and will not be discussed further at this point. If the token shows evidence of tampering, the session is terminated (step  1008 ). If the session has not been tampered with, the host verifies via the certificate chain whether it trusts the signer (step  1012 ). If the signer&#39;s certificate is not the certificate in the token, the host verifies that the signer is in the delegation list of those trusted to enforce authentication rules. If the signer is not trusted, then the session is terminated (step  1008 ). Otherwise, access to the host is allowed (step  1014 ). 
     It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions and a variety of forms and that the present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media such a floppy disc, a hard disk drive, a RAM, and CD-ROMs and transmission-type media such as digital and analog communications links. 
     The description of the present invention has been presented for purposes of illustration and description, but is not limited to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention the practical application and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.