Abstract:
The disclosed system and method provides an auto-rebuild feature in a digital device including a first memory device and a second memory device. When the digital device is initialized, the digital device checks the first memory device to determine if the first memory device includes a first boot sequence. If the first boot sequence is present, the digital device is booted using the first boot sequence on the first memory device. If the boot sequence is not present, the digital device reads a second boot sequence from the second memory device. The digital device then boots using the second boot sequence. The booting process of the second boot sequence reformats the first memory device, reads software from the second memory device and stores the software on the first memory device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 10/061,701 filed on Feb. 1, 2002. 
     
    
     
       TECHNICAL FIELD OF THE INVENTION  
         [0002]    The present invention relates in general to software security systems and, more particularly, to a system for auto-rebuilding a process-based system using flash memory.  
         BACKGROUND OF THE INVENTION  
         [0003]    Data processing systems have, as of recent, seen a large increase in the use thereof. For small users, such as home users, a typical system will run multiple programs that will allow access to various stored data files, allow the user to access resources such as disk drives, modems, faxes, etc. Access to these types of systems is typically what is referred to as “unrestricted”, i.e., any one possessing the required knowledge to access a given program can access it on any unrestricted computer. However, for a larger data processing system that may contain confidential information, the user may be provided access to resources that are billed on a time-use, etc., these systems usually requiring restricted access.  
           [0004]    In restricted access systems, a user is typically given an I.D. to the system. A system administrator can then configure a system, via a network or even a stand-alone system, to define the user&#39;s access to the system, once the user has logged in to the system. For example, in the network environment, there are a plurality of network drives, network resources such as printers, faxes and mailboxes, etc. The user has a configuration file that defines what access the user has. Upon logging in, the network will then access the configuration table and allow that user access to the given system resources. The user can then execute a program and utilize the program to access the resources through something as simple as a disk operating system (DOS). The disadvantage to this type of access is that the user now has full access to resources for any purpose, other than the purpose for which the user was given access.  
           [0005]    As an example, a user may need access to a modem for the purpose of running database searching software. This database searching software allows the user to dial up a provider with the modem to perform predefined searching. In order for a prior restricted system to utilize the modem, the user must be granted access to a given serial port. However, the user need not run the database searching software in order to have access to the modem. This allows the user to run other programs that can gain access to the system. The disadvantages to this is that, although the database searching software may have certain restrictions that are inherent in the software itself, a user can bypass this system to utilize the modem for other purposes. This can also be the case with respect to data files, wherein a word processing program has the ability to read and write files and gain access to printers through the word processing software. However, this access must be granted in a global manner, such that the user can access the files and printers via any other means, once logged into the system.  
           [0006]    As another example, consider a database that allows access to databases such as payroll, criminal records, etc., which a user has been given access. With current operating system security, the user can certainly go outside of a given program that is utilized with a specific database to copy, delete or even change files in the database outside of the program. As such, there exists a problem in that security for current operating systems provides that resources are allocated based on users or the groups to which the users belong. This therefore allows the user access to those resources even though the process that needs those resources is not being run. These rights will in turn allow the user to use the resource outside of its intended use.  
           [0007]    In a general purpose computer system operating with a wide assortment of applications or processes, usually as part of a bundled package, security is based on the control of user access which allows access to all of the resources on the system whether they are needed or not. A disadvantage of this system is that it is not very secure and is prone to break-in or misuse of resources, some of which contain very sensitive information, primarily because of the unrestricted access to resources. All that is required to enter such a system is a user ID and a password. One solution, implementing process-based access to a general purpose computer system, where the access to each resource is controlled in addition to the entry of a user ID and password, would provide an additional level of access control.  
         SUMMARY OF THE INVENTION  
         [0008]    The disclosed system and method provides an auto-rebuild feature in a digital device including a first memory device and a second memory device. When the digital device is initialized, the digital device checks the first memory device to determine if the first memory device includes a first boot sequence. If the first boot sequence is present, the digital device is booted using the first boot sequence on the first memory device. If the boot sequence is not present, the digital device reads a second boot sequence from the second memory device. The digital device then boots using the second boot sequence. The booting process of the second boot sequence reformats the first memory device, reads software from the second memory device and stores the software on the first memory device.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying Drawings in which:  
         [0010]    [0010]FIG. 1 illustrates a block diagram of an overall system;  
         [0011]    [0011]FIG. 2 illustrates a prior art security system;  
         [0012]    [0012]FIG. 3 illustrates a general block diagram of the system of the present invention;  
         [0013]    [0013]FIG. 4 illustrates a more detailed block diagram of the system of the present invention;  
         [0014]    [0014]FIG. 5 illustrates an alternate embodiment of the system of the present invention;  
         [0015]    [0015]FIG. 6 illustrates a flowchart depicting the operation of the present invention;  
         [0016]    [0016]FIG. 7 illustrates a flowchart depicting the resource request by the process;  
         [0017]    [0017]FIG. 8 illustrates a flowchart depicting the processing of the request by the operating system;  
         [0018]    [0018]FIG. 9 illustrates a functional block diagram of an embodiment of a process-based security system according to the present disclosure;  
         [0019]    [0019]FIG. 10 illustrates a flowchart of the operation of the embodiment of the process-based security system of FIG. 9; and  
         [0020]    [0020]FIG. 11 illustrates a flowchart of an example of use of a resource access table according to the embodiment of FIG. 9.  
         [0021]    [0021]FIG. 12 illustrates a functional block-diagram of a multi-user process based security system according to the disclosure.  
         [0022]    [0022]FIG. 13 illustrates a flowchart of an authentication process used in a process based security system.  
         [0023]    [0023]FIG. 14 illustrates a flowchart of a set password process used in a process based security system.  
         [0024]    [0024]FIG. 15 illustrates a flowchart of a key exchange process used with a process based security system.  
         [0025]    [0025]FIG. 16 illustrates a flowchart of a financial transaction using a process-based security system.  
         [0026]    [0026]FIG. 17 illustrates a flowchart of a secure file transfer process using a process-based security system.  
         [0027]    [0027]FIG. 18 illustrates a flowchart of a self-rebuilding function.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]    Referring now to the drawings, wherein like reference numbers are used to designate like elements throughout the various views, several embodiments of the present invention are further described. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated or simplified for illustrative purposes only. One of ordinary skill in the art will appreciate the many possible applications and variations of the present invention based on the following examples of possible embodiments of the present invention.  
         [0029]    Referring now to FIG. 1, there is illustrated an overall block diagram of a system for operating in conjunction with the security system of the present invention. A central processing unit (CPU)  10  is provided, which CPU  10  has associated therewith a microprocessor, peripheral circuitry, power supply, etc., all required to execute instructions and, in general, run programs. The CPU  10  has associated external therewith a keyboard  12  to allow the user to input the information thereto and a display  14 . A disk input system  16  is also provided which allows the user to download and upload data. The CPU  10  also has a local memory  18  associated therewith, the local memory  18  being in the form of random access memory, read-only memory, flash memory or other forms of memory. The CPU  10  may also include peripheral storage devices including flash memory, optical disk drives such as CD or DVD drives, hard drives, disk drives or any other form of data storage. The local memory  18  is operable to store both files in a region  20  and also execute programs in a region  22 . The files in the region  20  can also consist of data for databases. The CPU  10  can then access the executable files in the program portion  22 , execute the programs and access information in the form of files and/or data.  
         [0030]    The CPU  10  also interfaces with peripheral resources through an Input/Output (I/O) block  24 . The I/O block  24  allows access to such things as a modem  26 , a network card  28 , a scanner  30  and a printer  32 . The scanner  30  and the printer  32  are referred to as local resources. The modem/fax  26 , however, allows access to remote resources, such as a public telephone network (PTN)  34 . The network card  28  allows access to a network  36 , which in turn allows access to network resources  38 .  
         [0031]    Referring now to FIG. 2, there is illustrated a block diagram of a prior art security system. In prior art security systems, a user represented by a block  40  is allowed to access the system only upon providing the correct user I.D. A system administrator  42  is operable to pre-store configurations for the users in a user resource access template  44 . This user resource access template is accessed whenever a user is brought into the system and attempts to log in to the system. Once the user logs in, each user is given a predetermined configuration, this referred to as user access blocks  46 , there being one associated with each user. Each of these user access blocks  46  contain the configuration that was pre-stored by the system administrator  42  in the user resource access template. Once configured, this defines how the user is interfaced with the system, the system comprised of a plurality of system resources, represented by blocks  48 . In the example illustrated in FIG. 2, there are provided five system resource blocks  48 .  
         [0032]    It can be seen in the prior art system of FIG. 2 that there are three user access blocks  46 , representing three different user configurations, although there could be more, and five separate system resources, although there could also be more of these. The user access block associated with the user No.  1  is associated with system resource  1  and system resource  2 . User access block  46  associated with user No.  2  has access to system resource No.  1 , system resource No.  3  and system resource No.  4 . Associated user access block  46  provides a configuration that allows user No.  3  access to system resource  1  through  5 . It is noted that this is independent of the process upon which the user is working. The system resource is accessible by the user and not by the process.  
         [0033]    Referring now to FIG. 3, there is illustrated an overall block diagram of the present invention. In the present invention, security is based upon a process. A process, such as a word processing program, a financial program, etc., each have certain needs related to the resources. For example, a payroll program, once accessed, would need to have access to its database. The program, however, typically does not allow as an inherent part thereof for the database to be copied, does not allow the database to be deleted nor manipulated in any manner other than that provided by the program itself. These may even have audit trails that cannot be bypassed. The present invention provides for security wherein the resource is only accessible through the step of executing and running the program. If the program is not running, the user does not have access to the given resource unless through another process which happens to have access to the resource.  
         [0034]    Referring further to FIG. 3, a general operating system  60  is illustrated, this operating system being any type of operating system such as a Microsoft Windows based system, a UNIX system or even a DOS system. An operating system is the primary method by which a computer interfaces between the peripheral systems, such as memory storage devices, printers, modems and a process running on said computer. The user is then provided with a platform on which to run programs wherein the user can access the program and have the program access various peripherals through its interaction with the operating system. Operating system  60  therefore provides the necessary commands to access various resources  62  on the system. Again, these resources can be such things as a modem, a printer, a scanner, etc., even including a magnetic disk drive. The operating system is restricted to allocate only those resources defined in a resource access table  64 , which resource access table defines resources associated with a given process, which association is based upon the process&#39; needs.  
         [0035]    The process expresses its need via a process requesting mechanism  66  which is an inherent aspect of process execution for any given process. The process requesting mechanism  66  initiates a request for a resource and, if the process running on the system has access to that resource, as noted in the resource access table  64 , the operating system  60  will then grant the resource for use by the process within the operating system. If not, then the operating system will block access.  
         [0036]    Referring now to FIG. 4, there is illustrated a more detailed block diagram of the process-based access system of the present invention. In general, a user block  68  is provided which indicates a user of the system. The user of the system can access any given process, being illustrated for processes in process blocks  70 . Each of the process blocks  70  is connected to a process access selector  74 , each of which is associated with one of the resource blocks  62 , there being illustrated five resource blocks  62 . The process access selector  74  is operable to potentially allow any process to address that process access selector  74 . An access control block  76  is provided that receives as inputs an indication of which of the processes in process block  70  is running. A System Administrator block  75  is provided to allow a System Administrator to set the parameters of the access control block. The access control block then selects which of the process access selector blocks  74  is authorized to have access to a given resource. It is important to note that it is a request from a process block  70  during the running of that process that is utilized by the access control block  76  to grant access to the process access selector  74 .  
         [0037]    By way of example, if a word processing program were being operated and,on the same computer, a user had the ability to operate an accounting program, the word processor would be provided access to certain regions on a disk and the files associated therewith. The user could retrieve these files, delete them, modify them and restore them. However, the user would not be allowed through the word processor to access the accounting database for any purpose, since the process does not require this. In another example, if a modem were provided, this would not usually be a resource that was available to a word processor. The modem would, for example, only be accessible to a communications program.  
         [0038]    In another example of the operation of the process based security system, where resources are permitted access only in association with the particular process that is selected, reference is made to Table 1, which is an example of the resource access table  64  of FIG. 3:  
                           TABLE 1                       Step   Process name   Resource name   Rights Mask                   1   C:\*.*/S   C:\*.*/S   Full access               E:\LOGIN\LOGIN.EXE   Execute only       2   E:\LOGIN\LOGIN.EXE   E:\SYSTEM\PASSWORDS   Read only               E:\PROGRAMS\MENU\MENU.EXE   Execute only       3   E;\PROGRAMS\MENU\MENU.EXE   E:\PROGRAMS\MENU\SCREENS   Read only               E:\PROGRAMS\*.EXE/S   Execute only               E:\PROGRAMS\*.COM/S   Execute only       4   E:\PROGRAMS\WP51\WP.EXE   F:\LIBRARY\*.*   Full access               G:\COMMON\*.*/S   Full access                  
 
         [0039]    The example in Table 1 illustrates a general personal computer of the clone type, running an MS DOS operating system which is attached to a network with a process based security. When the computer is started, any process with the C:\ drive (denoted with the wild card processing of *.*) and its sub-directories (denoted with the /S option on the end of the process name) is provided full access to anything on the C:\ drive (once again denoted with the wild card resource name of *.*) and its sub-directories (once again denoted with the /S option on the end of the resource name). The user can also execute the process E:\LOGIN\LOGIN.EXE from the network. All other resources from the network are not available to the computer at this time. This situation represents a user, on a computer, who can log into a network, but has not done so. In essence, the user can do anything with their local resources, but nothing with network resources, until they are identified to the network with the login program.  
         [0040]    In step 2 in Table 1, when the user executes the E:\LOGIN\LOGIN.EXE process, the process changes from something on C:\ to LOGIN.EXE which can read the E:\SYSTEM\PASSWORDS file and execute the E:\PROGRAMS\MENU\MENU.EXE program. The file LOGIN.EXE is the network&#39;s method of identifying users of the network. Execution of LOGIN.EXE will verify the user through its read-only access to the E:\SYSTEM\PASSWORDS file. If the user is verified as a valid user, LOGIN.EXE will pass control on to step 3 and the process E:\PROGRAMS\MENU\MENU.EXE.  
         [0041]    In step 3, when MENU.EXE gets executed, it will read the appropriate menu options from its SCREENS file and display it for the user. MENU.EXE controls what programs can be executed and as such, it has been given rights to execute any program in the E:\PROGRAMS directory or any of E:\PROGRAMS sub-directories (this is denoted with the /S option after the partial wild card name *.EXE and *.COM). In step 4, in the event the user executes the WP.EXE program, this process has full access to a local F:\LIBRARY directory, a shared G:\COMMON directory and the sub-directories of G:\COMMON. The example in step 4 may also represent a network, where personal files are stored in a user-related directory (F:\LIBRARY) and company shared documents are stored in a common directory (G:\COMMON).  
         [0042]    In the preceding example, it can be seen that the user cannot, for example, obtain access to the PASSWORDS file by any other process except for the LOGIN.EXE process and this process determines how the user can deal with that particular file.  
         [0043]    Referring now to FIG. 5, there is illustrated an alternate embodiment of FIG. 4, illustrating how a particular process can constitute a resource. The resource blocks include a resource block  80  which constitutes a sixth resource, in addition to the five resource blocks  62 . However, this resource also has a process block  82  disposed therein, which constitutes a fifth process. Access to this process block  82  is facilitated through the use of a process access block  84 , similar to the process access block  74 , and controlled by access control  76 . Each of the processes in process blocks  70  have access to the process block  82  and the resource block  80  through the process access block  84 . Therefore, if one of the processes in process blocks  70  were running and the access control block  76  allowed access through a process access block  84 , then process No. 5  in resource block  80  could be run. This, of course, would then allow process block  82  and the process # 5  associated therewith to request and receive access to any of the resources in resource blocks  62  associated with process access block  74  in accordance with the access control information in access control block  76 . Although illustrated as only a single process that is accessed by another process, there could be many processes deep, such that three or four processes would need to be run before a given process was accessible which, in turn, could access an end resource.  
         [0044]    It is important to note that the process must be running and, during the running thereof, execute instructions that request a given resource. It is the running of the process and the request by that running process that allows access to a resource. The fact that the process has been opened and initiated is not sufficient to gain access to the resource since it is the use of the resource by a given process that is selected. For example, if a multi-tasking operating system were utilized and a given program executed from that platform as a first task, it may be desirable to place that task in the background and initiate a second task. Even if the first task were running in the background, the ability of the first task to request a given resource does not in any way effect the rights of the second task to have access to that same resource. Unless it is in the resource access table, no access to the resource will be allowed. Even if the first task were operating and it were utilized to “launch” a second process, this would not effect the resource access of the launched process, since when the launched process is running, the launching process is not running and it is not the launching process that is requesting access to the resource. Therefore, it is only the requesting resource that is of concern.  
         [0045]    Referring now to FIG. 6, there is illustrated a flowchart depicting the overall operation of the system. The program is initiated at a start block  100  and proceeds to a decision block  102 . The decision block  102  determines if a process has been initiated. If not, the program flows back around an “N” path to the input of decision block  102 . When a process has been initiated, the program will flow to a function block  104  to log in the user. The log in procedure is a procedure that may be utilized, but can be optional. In and of itself, as described above with reference to Table 1, the log in process is a separate process in and of itself. However, some programs by themselves, require log in procedures, i.e., accounting systems. Therefore, this is an optional block.  
         [0046]    After the log in block  104 , the program will flow to a function block  106  to run the process. Once the process is running, the program then flows to a decision block  108  to determine if a resource-request has been made by the running process. If not, the program will flow along the “N” path back to the input of function block  106 . When a resource request has been made by the running process, the program will flow from decision block  108  along a “Y” path to a function block  110 , wherein the resource access table is accessed to determine access rights for the requesting process. The program will then flow to a decision block  112  to determine if access has been granted for that particular resource. If not, the program will flow along a “N” path to a function block  114  to return an “access denied” error code. The program will then flow back to the input of function block  106 . However, if access rights have been granted in accordance with the resource access table, the program will flow along a “Y” path from decision block  112  to a function block  116  to allow access to the system and then back to the input of function block  106 . This will continue unless the resource is halted.  
         [0047]    Referring now to FIG. 7, there is illustrated a flowchart depicting the resource request by the process, as in step  108  of FIG. 6. The flowchart is initiated at a block  120  and then proceeds to a decision block  122 , wherein the process determines if a resource is needed for the process. If not, the program flows along an “N” path back to the input of decision block  122 . If a resource is required, the program will flow along a “Y” path to a function block  124 . The function block  124  then determines the ID for the resource and then generates the request, this request defining the resource that is required and also the mode of access that is required. The program will then flow to a decision block  126  to determine if the resource is available. If not, the program will flow along an “N” path back to the input of decision block  122 . If it is available, the program will flow along a “Y” path to a function block  128  to process the resource in accordance with the operation of the process and then flow to a return block  130 .  
         [0048]    Referring now to FIG. 8, there is illustrated a flowchart depicting the operation of the operating system when processing a request for a resource. This is initiated at a block  134  and then proceeds to a decision block  136 . The decision block  136  determines whether a resource request has been received from a process operating in conjunction with the operating system. If not, the program will flow along an “N” path back to the input of decision block  136 . If a resource request has been received, the program will flow along the “Y” path to a function block  138 . Function block  138  fetches the information stored in the resource access table to determine if the particular resource has any access rights associated therewith. The program will then flow to a decision block  140  to determine if access rights are present in the resource access table for the requested resource. If not, the program will flow along the “N” path to a function block  142  wherein a “NULL” signal is sent back to the requesting process to deny access and then to the input to decision block  136 .  
         [0049]    If access rights exist in the resource access table for the given resource, the program will then flow to function block  144  to determine if the mode of access that is requested by the requesting process is present in the resource access table, i.e., whether the resource access table has been set up to grant this mode of access to the given resource. An example of this would be a file that is defined as the resource with the modes being READ and WRITE, with either reading of the file from the disk or writing of the file to disk. The program will then flow to a decision block  146  to determine if the mode of access is available. If not, the program will flow along the “N” path back to the function block  142  and, if the mode of access is available, the program will flow along the “Y” path to a decision block  148  to determine if the requested resource and mode of access are valid for the requesting process. For example, a process may request access to a particular memory device or portion of a memory device and it may require access to that memory device for writing of information thereto. The system will first determine if the resource has access rights associated therewith and then check to see what mode of access is allowed. In this example, if the resource is available, it may have a mode of access available for reading and a mode of access available for writing. However, the resource access table may only grant reading rights to the requesting process. In this event, access will be denied. This is represented by the path that flows along the “N” path back to function block  142 . If access is allowed, the program will flow along a “Y” path from decision block  148  to a function block  150  to grant access and then to a return block  152 . The following is the process flow for the process generating the request:  
         [0050]    Process  
                                                                                                   id = fopen (“filename”, “rt”);             This is the request to                the operating                system for the file                access (resource).                if (id == NULL)                {           file not available           }                else   {                process the opened file           }                      
 
         [0051]    The following is the process flow for the operating system when servicing the request:  
         [0052]    Operating System  
                                                                                                                           FILE *fopen (char *name, char *mode)                {                (before checking for the presence of the file,           check to see if the process has any rights to the file.)            for (i = ø; i&lt;SIZE_OF_ACCESS_TABLE; i + +)                if (check (name, accesstable [i]. resource) == ø)                break;            if (i == SIZE_OF_ACCESS_TABLE) return NULL; (no rights at all)       for (j = ø; j&lt; accesstable [i]. rights_size; j ++)                if (check (mode, accesstable [i]. rights [j]. Mode) == ø)                break;            if (j == accesstable [i] rights size) return NULL; (specific right not       present)                (the remaining code deals with what the operating           system needs to do to allocate the file to the calling           process (note additional errors may still occur, like           file not found)).           }                      
 
         [0053]    The foregoing describes a system for providing process-based security to an operating system. In this security system, access to any resource on the system, although provided by the operating system, is restricted by the operating system to only those requested by a given process. Whenever a process, during operation thereof with the operating system, requires or requests access to a resource, the operating system makes a determination as to whether a resource can be made available for that given process. This is facilitated by storing access rights for any process in a resource access table. When a process is running on the system and it requests for its use a given resource, the operating system will then look up in the resource access table to determine if the resource is available and, if so, grant access to the resource.  
         [0054]    It has been described hereinabove that a process-based security system controls access to resources via the process (i.e., application) that requests the resource. Experimentation and development have shown, however, that such a security system is is particularly efficient when implemented in a dedicated, or single-purpose environment, such as a web server, or other, computer appliance-type of application.  
         [0055]    Thus, it can be appreciated that the process-based security described hereinbelow, as applied to a dedicated, single purpose computer system, could exhibit the following advantages:  
         [0056]    (1) prevent a user from loading their own applications into the system;  
         [0057]    (2) prevent a user from attempting to access files from uncontrolled processes, e.g., trying to load in a hex editor to obtain access to the sensitive files such as accounting records, etc.;  
         [0058]    (3) prevent access to all the resources in a system, even though individual resources are needed by a particular program or process;  
         [0059]    (4) process-based security, in a dedicated environment, is self contained, i.e., independent of the rest of the system, and is thus relatively easy to implement in existing systems;  
         [0060]    (5) process-based security is context-specific or can be made to be dynamic by the way in which resource access is interpreted; and  
         [0061]    (6) in a process-based security system, the user only has the right to execute a specific application or process and that process includes access rights only to specific resources keyed to the requesting process.  
         [0062]    Referring to FIG. 9 there is illustrated a functional block diagram of an illustrative embodiment of a process-based security system according to the present disclosure. A portion of the functional aspects of a complete computer system  160  is shown having an operating system  162  coupled with a plurality of resources indicated by the three blocks identified by reference number  172 , respectively resource A, resource B and resource C. In general, resources  172  may be various types of input and/or output devices or application programs installed on a particular system. I/O device resources may include a keyboard, mouse, scanner, display, modem, disk drive, printer, or an interface to a network, etc. Application, or process type resources may further include a word processor, a spreadsheet, a communication or e-mail program, a database, a search engine or browser and the like. Continuing with FIG. 9, each process requesting access  168  is bound to a resource access table (RAT)  164  via respective links  165 ,  166  and  167 . The resource access tables  164  contain entries or statements that may be expressed in a high level programming language. Further coupled as inputs to operating system  162  are the plurality of processes requesting access  168 , i.e., applications running on system  160  as indicated by process requesting access  1 , process requesting access  2  and so on to process requesting access N. In the description to follow, the words application and process will be used interchangeably, referring generally to an application program as distinguished from an operating system. Such application programs are provided to accomplish specific operations such as spread sheets or word processing or communications and the like. In general, each of these processes or applications  168  will, during their operation, require access and use of various ones of the resources  172  coupled to the operating system  162  of the computer system  160  of the present disclosure. Coupled as inputs to the various processes  168  or applications  168  is provision for entering a user identifier and/or password for each respective process  168  or application  168  that will be requesting access to a resource as will be described further hereinbelow. The entry of the user identifier and/or password is represented by the functional block  170  user ID and password.  
         [0063]    Referring further to FIG. 9, an operating system  162  for computer system  160  is illustrated, such as a Microsoft Windows based system, a UNIX system, a DOS system or the like. An operating system is the primary method by which a computer interfaces with the various resources including, for example, the peripheral systems such as memory storage devices, printers, modems and a process or application running on said computer. The operating system  162  provides the user with a platform on which to run programs, i.e., applications or processes  168  wherein the user can access the program and have the program access various peripherals through its interaction with the operating system. Operating system  162  therefore provides the necessary commands to access various resources  172  on the system. Further, the operating system  162  is restricted to allocate only those resources defined in the resource access tables  164 , which define resources  172  to be associated with a given process  168 , based upon the needs of the process  168 .  
         [0064]    The operating system  162  (OS  162 ) receives as inputs an indication of which of the process blocks  168  is running. In one embodiment the OS  162  may include or be responsive to a System Administrator function to set the parameters of the access control for the resources  172 . The OS  162  in conjunction with the resource access table  164  then selects which of the resources  172  is authorized access. It is important to note that it is a request from a process  168  during the running of that process  168  that is utilized by the OS  162  to grant access to the resource access table  164 .  
         [0065]    Continuing with FIG. 9, the functional block  170  indicates both a user of the system and information that may be provided by the user to gain access to the system or its resources. The user of the system can access any given resource appropriate to the application that is provided in the dedicated system. In general, a process or an application is an executable file which may be referred to as “*.EXE”, the “*” defining a wild card name of one or more characters representing an executable file or program. For example, one well known word processing program has an executable file name of WP.EXE. The user can enter the term “WP” and “launch” that program. The program will then run in a conventional manner.  
         [0066]    In operation of the system  160  of FIG. 9, by way of example, if a word processing program were being operated and, on the same computer, a user had the ability to operate an accounting program, the word processor would be provided access to certain regions on a disk and the files associated therewith. The user could retrieve these files, delete them, modify them and restore them. However, the user would not be allowed through the word processor to access the accounting database for any purpose, since operation of the word processor process does not require this. In another example, if a modem were provided, this would not usually be a resource that was available to a word processor. The modem, for example, could only be accessed by a communications program.  
         [0067]    In an example of the operation of a process based security system, reference is made to Table 2:  
                           TABLE 2                       Step   Process or application name   Resource name   Rights Mask                   1   C:\*.*/S   C:\*.*/S   Full access               E:\LOGIN\LOGIN.EXE   Execute only       2   E:\LOGIN\LOGIN.EXE   E:\SYSTEM\PASSWORDS   Read only               E:\PROGRAMS\MENU\MENU.EXE   Execute only       3   E;\PROGRAMS\MENU\MENU.EXE   E:\PROGRAMS\MENU\SCREENS   Read only               E:\PROGRAMS\*.EXE/S   Execute only               E:\PROGRAMS\*.COM/S   Execute only       4   E:\PROGRAMS\WP51\WP.EXE   F:\LIBRARY\*.*   Full access               G:\COMMON\*.*/S   Full access                  
 
         [0068]    For purposes of illustration, the example in Table 2 applies to a personal computer (PC) which is attached to a network and running an MS DOS operating system that is provided with process-based security. Although a PC is usually considered a general purpose system, the simplicity of the illustration provided by Table 1 applies equally well to a dedicated computer system. When the computer is started, as in step 1 in Table 1 described previously, any process to be run with the C:\ drive (denoted with the wild card designation *.*) and its sub-directories (denoted with the /S option on the end of the process name) is provided full access to any resource on the C:\ drive. Note also that the user can execute the resource E:\LOGIN\LOGIN.EXE from the network but that all other resources from the network are not available to the computer at this time as being limited by the statement E:\LOGIN\LOGIN.EXE. This statement will be described further in the next paragraph. This example, so far, represents a user, on a computer, who can log into a network, but has not done so. In essence, the user can do anything with his or her local resources, but nothing with network resources, until they are identified to the network with the login program.  
         [0069]    In step 2 in Table 2, when the user executes the E:\LOGIN\LOGIN.EXE process, the process changes from something on C:\ to LOGIN.EXE which is permitted to read the E:\SYSTEM\PASSWORDS file and execute the E:\PROGRAMS\MENU\MENU.EXE program. The file LOGIN.EXE is the network&#39;s method of identifying users of the network. Execution of LOGIN.EXE will verify the user through its read-only access to the E:\SYSTEM\PASSWORDS file. If the user is verified as a valid user, LOGIN.EXE will pass control on to step 3 and the process E:\PROGRAMS\MENU\MENU.EXE.  
         [0070]    In step 3, when the file MENU.EXE is executed, it will read the appropriate menu options from its SCREENS file and display it for the user. MENU.EXE controls what programs can be executed and as such, it has been given rights to execute any program in the E:\PROGRAMS directory or any of E:\PROGRAMS sub-directories (this is denoted with the /S option after the partial wild card name *.EXE and *.COM as listed in the resources column of Table 2). In step 4, in the event the user executes the WP.EXE program, this process has full access to a local F:\LIBRARY directory, a shared G:\COMMON directory and the sub-directories of G:\COMMON. Step 4 may also represent a network, where personal files are stored in a user-related directory (F:\LIBRARY) and company shared documents are stored in a common directory (G:\COMMON).  
         [0071]    In the preceding examples illustrated by Table 2, it can be seen that the user, because of the table which must be accessed during a resource request, cannot obtain access to the PASSWORDS file by any other process except via the LOGIN.EXE process. This process also determines how the user can deal with that particular file.  
         [0072]    Referring now to FIG. 10 there is illustrated a flowchart of the operation of the illustrative embodiment of the process-based security system of FIG. 9. The flow begins with the Start block  200  and proceeds to block  204  to load the application program. From block  204  the flow proceeds to block  206  to start the application which is followed by decision block  208  to determine whether a resource is requested by the application. If the result of the determination is negative then the flow follows the N path back to the entry to the Start Application block  206 . If the determination in block  208  is affirmative then the flow proceeds to block  218  wherein a step to read the respective resource access table  164  for the requesting application  168  is performed.  
         [0073]    Continuing further with FIG. 10, upon reading the resource access table  164  for the requested application in block  218  the flow proceeds to block  220  wherein the system  160  interprets the entries or statements in the resource access table  166  to identify the commands of the execution path and the sequence of operations contained in it. The flow thereupon proceeds to decision block  222  wherein a determination is made as to whether the request for resource access matches the application in operation. If the determination is negative, then the flow proceeds to block  216  wherein access is denied and thereupon is routed back to the start application block  206 . If, however, the determination in decision block  222  is affirmative, then the flow proceeds along the Y path to block  226  wherein access is granted to the requested resource and the flow returns to the main program to execute the application or process as indicated at block  234 . It will be appreciated that the security access is provided by the reading and interpreting of the resource access table  164  entries or statements which specify the resources needed for the particular application or process and the execution path for access to those resources. Thus, access to resources is limited to only those resources that are needed and requested by the particular application or process that is in operation.  
         [0074]    A study of FIGS. 9 and 10 described hereinabove will reveal the following operational characteristics of a process-based security system for dedicated or single-purpose computer systems. Upon launching an application in a process-based system, the access rights are associated or bound to the launched application as indicated by links  165 ,  166  and  167  in FIG. 9. During the request for access to the needed resource(s), the access rights associated with that program are checked. In a general purpose system, security checks impede processing by interrupting the OS while the security check is performed each time a user requests a resource. In a dedicated system running one process or a single process combination, only one request for resource access is required; if several process combinations are provided, the system selectively allows access to the resources appropriate to the process requesting access. In either case, the request occurs during the initial steps of the process. Further, the security access is performed by matching the conditions present upon launching the application such as the program identity, user identity and password, execution path through the directory, etc. with the resource access entries or statements in the respective resource access table  164 . Once the application is launched, read and write calls are no longer checked, and the resource access table  164  controls “the traffic”—the execution path through the directory. As an example, in a web server application, the steps, briefly, would be: (1) turn on the web server; (2) launch the application; (3) read and interpret the resource access table entries; (4) grant the needed access; and (5) execute the application, including the allowed resources.  
         [0075]    During the interpretation step  220  of FIG. 10 of the illustrated embodiment, resource access table entries are interpreted, one character at a time, instead of merely reading a resource name associated with a listed process or merely making a string comparison, because of the presence of meta symbols embedded into the entries in the respective resource access table  164 . Meta symbols, as disclosed herein, are textual devices which may be inserted into resource access table entries as second-order data or instructions to supply additional related information or modify the interpretation of the entry in some way. In the comparison process to find a resource in the resource access table, entries do not have to be static. Entries in the resource access table can have meta symbols to allow for context sensitivity to the process making the request. Table 3 presents some examples of meta symbols developed for the embodiment of the present disclosure which may be included in a resource access table entry. Meta symbols are assigned—and construed—in a UNIX environment.  
                   TABLE 3                       Meta           Symbol   Definition/Meaning                   $P   If the requested resource name matches to this point, consider           the entry a match (path wild-card).       $C   The particular character in the requested resource name matches           this symbol no matter what (character wild-card).       $D   For a single level of depth in the directory, this symbol means a           match (directory wild-card).       $$   Requested resource name must match a $ at this point.       $S   Requested resource name must end (suffix) in the text following           this symbol.       $U   Requested resource name must have the user name of the user           that initiated the process making the request, at this point.       $G   Requested resource name must have the group name of the           group that initiated the process making the request, at this group.                  
 
         [0076]    As described in the foregoing, to provide process-based security access in a single-purpose “appliance” computer system, a resource access table (RAT) is bound to, i.e., associated with, the requesting process when the process or application is launched. The RAT contains entries in which the defined execution paths, i.e., process paths, are modified using meta symbols. These meta symbols provide instructions for interpreting the process or execution paths. For example, meta symbol entries enable the system to determine which part(s) of an entry in a RAT must be matched character-by-character to produce a valid comparison or which part(s) may be ignored or which part(s) has a substituted instruction, etc., in order to be granted the security access rights associated with that particular entry in the RAT. Each entry or statement in the RAT may correspond to a resource whose access is defined by the entry.  
         [0077]    For example, an unmodified entry in a RAT might appear as:  
         [0078]    PROGRAMS/WP/WP.EXE  
         [0079]    and the resources to be associated therewith might be:  
         [0080]    /HOME/$U/$P.  
         [0081]    So, when a user initiates a program operation the command string is compared to the RAT entry. In this example, the meta symbol $U means that the current user name is substituted into the entry and permitted access to the respective resource. Similarly, the $P modifies the RAT entry and means that the rest of the path is ignored, i.e., it is “matched” no matter what the rest of the path is.  
       EXAMPLE NO. 1  
       [0082]    Referring now to FIG. 11, suppose the user Q is operating in the home directory and wishes to delete a file xyz. In FIG. 11, the perspective is that of the operating system. The routine begins with the start block  240  and proceeds to function block  242  wherein the operating system (OS) receives a request to run DEL program. Thereafter the OS checks in block  244  whether the current user is allowed a DEL command. If not, the flow follows the N path and returns to enter block  242 . If so, the flow proceeds to block  246  to load the DEL command and fetch the corresponding access rights from the resource access table (RAT)  166 . In this case the RAT  166  entry is the statement: /HOME/$U/$P which defines access rights in the HOME directory for the $U current user within which access is allowed $P from this point on, i.e., is unrestricted in directory depth per Table 3.  
         [0083]    Continuing with FIG. 11, in the next step, at decision block  248 , the OS determines whether the access rights match the current user and if affirmative, the flow proceeds along the Y path to another decision block  250 . There, if both the HOME directory and the current user $U are matched, the routine advances to block  252  where access is granted and the DEL command is allowed to be executed. The routine returns to the main program in block  254 . In either case, in blocks  248  or  250 , the result is that a match did not occur, access is denied and the routine returns to the entry of block  242 .  
       EXAMPLE #2  
       [0084]    Suppose the user is operating in the HOME directory, and wishes to run a word processor (e.g. WordPerfect). The word processor program (application or process) is in the directory: /PROGRAMS/WP/WP.EXE. Here, the resource access table statement is: /HOME/$U/$S.WP, where $S is used as an intervening suffix. This statement limits access to files in the user&#39;s home directory (/HOME/$U/) that end in the characters WP ($S.WP).  
         [0085]    It will be appreciated in the foregoing example that any resource can be moved to any place in an execution path it is desired, merely by defining the access rights for that path in the Resource Access Table. Thus, the access rights “move” with the new placement of the resource. Further, many resources, e.g., utility programs, can be wild carded into part of an execution path. In effect, these programs are executed, not out of the original program or process but out of the resource access table  166 . This provides a simple way to limit access rights—merely by statements in the resource access table. Moreover, since the substituted directory path identified the word processor WP in its execution path—and not some other resource such as an EXCEL program—access rights to EXCEL (or any other program that may be part of the system) are excluded from the WP program execution path.  
         [0086]    Suppose, alternatively, the user is running EXCEL and wishes to use a spell check resource. Unless that spell check resource, which resides in the WP program, is included in the allowed access rights of the RAT entries for the EXCEL program any user attempt to access it from EXCEL will be denied. It will thus be appreciated that the process-based security described hereinabove provides the advantages of (1) preventing users from loading their own applications on a dedicated system configured according to the present disclosure; and (2) preventing users from attempting to access files via uncontrolled ways such as trying to load in a hex editor, e.g., to obtain access to accounting or other sensitive files.  
       EXAMPLE NO. 3  
       [0087]    Consider a web server (WS) which can execute any common gateway interface (CGI) serving a plurality of companies, e.g., A, B, C, D, E and F. Prefixing is used to distinguish whose CGI is allowed execution (e.g., ABC/CGI for access to ABC/DATA directory but which may exclude DEF/CGI) by substitution according to a $E(#) meta symbol that identifies the path that is executable out of the original structure in the RAT. In the RAT, as illustrated in Table 4 hereinbelow, it is seen that there are two kinds of entries instead of one: one statement for the web server, another for the CGI for which access rights are defined. Table 4 illustrates a fragment of the RAT for Example 3.  
                               TABLE 4                                   Web Server   CGI   Rights                           /HTTP                       /PROGRAMS/$D/$P   Execution           /PROGRAMS/$D/$P               $E(2)/DATA/$P   Read, Write                      
 
         [0088]    Here, the path /PROGRAMS/ABC is granted access, according to the statement $E(2)/DATA/$P.  
         [0089]    The resource access table  166  entries, thus modified by meta symbols, as described hereinabove, define both the access to resources and the execution path through the directory. The resource access table  166 , uniquely determined for the dedicated, single purpose system, is called by the request for access made by the application or process. Thus, the entries in the resource access table are, at the same time, both statements of the access rights and statements of the execution path. In some operations, for example, a meta symbol (identified by a $ followed by a character) inserted into a statement in the resource access table may provide for, referring to Table 3:  
         [0090]    (1) association of user identity information with the application or process (user ID and a password, e.g.);  
         [0091]    (2) substitution of one user or a group of users for another user;  
         [0092]    (3) substitution of a part of one execution path for another one;  
         [0093]    (4) specifying at what point in the directory path the access begins, or how far into the directory the access rights extend; and  
         [0094]    (5) specifying an access path limited to a particular file name or keyed to the access of a particular file. The meta symbols enable modifications to the entries in the resource access table  166  with instructions that define, on the fly, the particular access rights available to a particular process. Thus, instead of just performing a string comparison of the access rights string (with a predetermined set of access rights) the string is read and interpreted, based on its content, as it proceeds on the execution path.  
         [0095]    In summary, the process-based security as disclosed hereinabove is most efficiently applied to specific functions. The operating system  162  of the dedicated, single-purpose system  160  is bundled only with the specific applications  168  needed including the resource access tables  166  and the necessary code to implement the use of the meta symbols and the process-based security access. Only internal resources are affected. Requests for access to resources  172  are processed from within the particular process or application  168  before invoking the operating system  162  but before the request handler is invoked.  
         [0096]    With reference to FIG. 12, a multi-user process based security system is shown. In the case where the computing environment is a computer, the multiplicity of users may be accessing the system sequentially. In the case where the computer environment is shared, such as a server with a multiplicity of clients, the users may be accessing the system simultaneously.  
         [0097]    A first user  300  is authenticated by an authentication agent in the operating system  60  or process-based security module  76  of a computer. Once the first user  300  has established an authenticated identity, the process based security system loads the first user resource access table  312  in database  310 . The first user resource access table  312  includes permissions, establishing the resources available to each process that is available to the first user. A first process permission table  314  includes a list of files, directories and other processes that may be accessed by the first user  300  through the first process  302 . A second process permission table  316  includes a list of files, directories and other processes that may be accessed by the first user  300  through the second process  306 . The first process  302  sends calls to the OS  60 , requesting access to a resource  324 . A process-based security module  76  consults database  310  for the first user resource access table  312 , including the first process resource access table  314 . If the requested resource  324  is identified in the first process resource access table  314  of the first user resource access table  312 , first process  302  is given access to the requested resource  324 .  
         [0098]    When the first user  300  accesses a second process  306 , the second process  306  is given access to resources  326  in accordance with a second process resource access table  316  in the first user resource access table  312 . The resources  324  available to the first user  300  in the first process  302  will only be available to the first user  300  in the second process  306  where the resource  324  is identified as available to the first and second processes in their respective process resource access table in the first user resource access table  312 .  
         [0099]    A second user  304  is authenticated by the operating system  60 . The process-based security module  76  reads the second user resource access table  318  in database  310 . When the second user  304  accesses the first process  302 , the process-based security module  76  checks the first process  302  access permissions with reference to the second process resource access table  320  of the second user resource access table  318 . If the second user  304  does not have permission to access the second process  306 , there is no second process resource access table in the second user resource access table  318 , or the second process resource access table for that user is given a null value. A third process  308  accessed by the second user  304  is governed by the third process resource access table  322  of the second user resource access table  318 .  
         [0100]    The resources available to the first process  302  depend on the identity of the user that has been identified to the system. The use of a user name meta-symbol ($U) in the resource access tables allows the system to identify resources based on the name of the user associated with the process. For example, the resource access table may provide permission for each user to a directory that has been named using the user name. The multi-user process based security system is particularly useful where the system is a web-server or any system having multiple users and a need to control access.  
         [0101]    Because the operating system checks the authorization of every resource call, the security of data, such as password files, does not need to depend on encryption or other forms of masking. Typical prior art systems do not save passwords in cleartext, but instead save hashes of the passwords. When the password is set using a set password function, the password is hashed and stored in association with a username. A login process may request a username and password. The password is hashed and the username is used to retrieve the hash of the password associated with the username. If the two hashes match, the user is authenticated.  
         [0102]    In accordance with the preferred embodiment, a given resource can only be accessed by an authorized user using an authorized process. This allows a password file to be stored as cleartext, which allows greater flexibility in the use of the password in key exchange protocols.  
         [0103]    With reference to FIG. 13, a flowchart of an authentication process is shown. The authentication process involves interactions between a user, an authenticating process and an authentication module. The user may be an individual interacting with a single machine, a process accessing an authenticating process, a client in communication with a server, or any other interactive source of data. The authenticating process may be any process that makes an authentication call. A typical authenticating process is a login process. Any process that requires or needs authentication of a user may be an authenticating process. Some of the functions ascribed to the client or user may be performed by the authenticating process.  
         [0104]    The authentication module works in conjunction with the process based security system to authenticate users to any process that calls on it. In the simplest embodiment, the authentication module receives usernames and passwords and compares the received password with a stored password associated with the username. In accordance with the preferred embodiment, the authentication module uses a handshaking operation to authenticate the user.  
         [0105]    The user or client initiates the authentication process in step  330 . The authentication process may be initiated by executing a login program, by executing a task that calls on a login program, or by selecting some function in a program that requires authentication before it will proceed. When the authentication process has been initiated, the authenticating process sends a request for a random number (RN) from the authentication module at step  332 .  
         [0106]    When the authenticating process sends a request for a random number to the authentication module, the operating system using process-based security will check to see if the authenticating process is authorized to access the authentication module. Only the processes listed in the resource access table will be able to access the authentication module.  
         [0107]    The authentication module generates a random number (RN) in step  334 . In accordance with the preferred embodiment, the random number (RN) is a sixteen byte cryptographically strong random number. In accordance with the preferred embodiment, the system uses random numbers that are cryptographically strong random numbers, created using processed noise. Other forms of random numbers may be used, as appropriate, including pseudo-random numbers. Pseudo-random numbers may be necessary in protocols where the random numbers need to be reproducible. Preferably, the random numbers are sixteen byte random numbers, although any length random number may be used as appropriate. The authentication module modifies the authenticating process&#39; task structure to reflect the pending authentication request and to restrict access to data storage where the random number (RN) will be stored in step  336 . The random number is stored (RNs) at a designated storage location with restricted access in step  338 . The random number (RNa) is also sent to the authenticating process in step  340 . RNs=RNa  
         [0108]    The user enters a username (USERID) and a password (PWa) in step  342 . In a client/server environment, where a process run on the client machine is calling an authenticating process on the server, the username (USERID) and password (PWa) may be kept at the client. In this case, the authenticating process may forward the random number (RNa) to the client. The client uses the password (PWa) and the random number (RNa) to generate a hash H(PWa,RNa) at step  344 . In accordance with the preferred embodiment the password (PWa) and the random number (RNa) are concatenated, with the concatenation serving as the data hashed. A keyed hash function, such as a keyed MD5 hash, may use the password (PWa) as the data hashed and the random number (RNa) as the key (K).  
         [0109]    In a local environment where a user is communicating directly with the authenticating process, the user submits the username (USERID) and password (PWa) to the authenticating process. The authenticating process generates the hash H(PWa,RNa).  
         [0110]    In either case, the username (USERID) and the hash H(PWa,RNa) is sent to the authentication module in step  346 . The authentication module checks the task structure of the authenticating process to determine if there is an outstanding request for authentication in step  348 . If there is no outstanding request for authentication, the authentication module does not proceed with the authentication process. This deters a malicious user from using a brute force attack against an unchanged stored random number (RNs) by submitting false hashes H(??, RNs) until authentication is achieved. By performing this check of the task structure, the authentication process changes the random number (RNs) for each attempted authentication, reducing the effectiveness of a brute force attack.  
         [0111]    If the task structure of the authenticating process shows a pending request for authentication, the authentication module retrieves the stored random number (RNs) in step  350 . The authentication module retrieves a stored password (PWs) associated with the username (USERID) at step  352 . The authentication module uses the stored password (PWs) and the stored random number (RNs) to calculate a hash H(PWs,RNs) at step  354 . The received hash H(PWa,RNa) is compared to the calculated hash H(PWs,RNs) at step  356 . If the hashes are equal, H(PWa,RNa)=H(PWs,RNs), then the user is authenticated. If the hashes are not equal, the authentication process fails.  
         [0112]    In either instance, the authentication module modifies the task structure of the authenticating process to reflect the completion of the pending authentication process at step  358 . This prevents further attempts at authentication without generating a new random number (RN). The authentication module may set the user as the username (USERID) in the task structure of the authenticating process in step  360 . The authentication is communicated to the authenticating process, which may set the user as the username (USERID) for the application settings in step  362 .  
         [0113]    With reference to FIG. 14, a flowchart for a set password routine is shown. A set password process communicates with an authentication module. The set password process receives an entered username (USERID) in step  635 . The users present password (PW) is entered in step  368 . Both the username (USERID) and the password (PW) are sent to the authentication module, where an authentication process is performed in step  366 . If the password (PW) is associated with the username (USERID), the authentication is conformed in step  369  and the set password program requests a new password (PWN) in step  370 . The new password (PWN) is sent to the authentication module. The authentication module sets the password (PW) equal to the new password (PWN) and saves the associated username (USERID) and password (PW) in step  372 . If the user cannot be authenticated, the process stops.  
         [0114]    With reference to FIG. 15, a flowchart for a key exchange process is shown. The key exchange protocol is shown as conducted between a client and server, where the server is operating with a process-based security system. Those having skill in the art will recognize that the key exchange can be performed between any process and a process-based security operating system. In accordance with the preferred embodiment, the functions ascribed to the server are performed primarily by an authentication module operating in conjunction with the operating system.  
         [0115]    The client, or more specifically a process operating in a client relationship with a server, requests a key exchange from the server in step  374 . The client sends the username (USERID) to the server in step  375 , unless the user has already been authenticated to the system, in which case the server uses the authenticated username. A user enters a password (PW) at the client at step  377 . The password (PW) is typically not transmitted to the server.  
         [0116]    The authentication module in step  376  modifies the client task structure to reflect the key exchange process initiation. The server generates a first random number (RN 1 ) in step  378  and sends the first random number (RN 1 ) to the client. In accordance with the preferred embodiment, the system uses random numbers that are cryptographically strong random numbers, created using processed noise. Other forms of random numbers may be used, as appropriate, including pseudo-random numbers. Pseudo-random numbers may be necessary in protocols where the random numbers need to be reproducible. Preferably, the random numbers are sixteen byte random numbers, although any length random number may be used as appropriate. Depending on the hash function used, the length of the random number and the strength of the randomization function may affect the strength of the key generated, so the random number generation process used should be chosen accordingly.  
         [0117]    The server retrieves the password (PW) associated with the username (USERID) from data storage in step  382 . Both the client in step  382  and the server in step  384  independently calculate a hash H(PW,RN1) based on the password (PW) and the first random number (RN 1 ). In accordance with the preferred embodiment, a keyed MD5 signature function is used as the key generating hash function. Other signature or hash functions with sufficient pseudo-random distributions may be used. A first key (K 1 ) is set as equal to the hash H(PW,RN 1 ) in step  386  at the client and step  388  at the server. In one embodiment, the first key (K 1 ) may be used as a symmetric key for all communications between the client and server for the session. In the preferred embodiment, the server sends a second random number (RN 2 ) to the client in step  392 , and a second hash is performed by both the client in step  394  and server at step  396  H(PW,RN 2 ) to generate a second key (K 2 ) at step  400  for the client and  398  for the server. The first key (K 1 ) may be used to symmetrically encrypt communications from the server to the client, while the second key (K 2 ) may be used to symmetrically encrypt communications from the client to the server. Once the keys are generated, the authentication module modify the task structure for the client in step  402 , ending the key generation process.  
         [0118]    The process-based security system can be used to facilitate secure financial transactions over a network. A typical Internet commerce system allows users to make purchases using a credit card. In order to save the user time and encourage further purchases, the Internet commerce system may save the credit card number, as well as other data used to validate the credit card number such as the expiration date or CCV number. In the event that the Internet commerce system server is compromised, either by hackers or insiders, the credit card numbers may be stolen and abused. Implementing a process-based security system on the Internet commerce system server could secure the credit card number database, but in some cases the implementation may be too extensive a change.  
         [0119]    With reference to FIG. 16, a flowchart for a secured financial transaction in accordance with one embodiment is shown. The transaction is performed by a buyer at a point-of-sale server (POS). The point-of-sale may be a POS terminal at a retail store or a personal computer communicating with an Internet commerce server or any other server operative in creating a financial transaction between a buyer and a financial institution. The point-of-sale server is communicably connected to a process-based security server and a financial server.  
         [0120]    When the buyer initiates the purchase at the point-of-sale server at step  404 , the buyer is typically authenticated to the point-of-sale server using a standard authentication technique. With knowledge of the buyer&#39;s identity, the point-of-sale server retrieves one or more stored portions of credit card numbers in step  406 , allowing the buyer to choose one of those credit card to complete the transaction. Because the storage of credit card numbers at the point-of-sale server is insecure, in accordance with one embodiment, the point-of-sale server displays only the last four numbers of the credit card numbers, uniquely identifying the buyer&#39;s credit cards without revealing the actual credit card number.  
         [0121]    When the buyer has selected a credit-card to use for the purchase in step  408 , the point-of-sale server correlates a credit card identifier with the portion of the credit card number that has been selected. The credit card identifier is a number previously defined by the process-based security server to serve as a representation of the credit card in communication between the point-of-sale server and the process-based security server. The point-of-sale server sends the credit card identifier to the process-based security server, along with any necessary transaction data such as the amount of purchase in step  410 .  
         [0122]    The process-based security server receives the credit card identifier and retrieves the associated credit card number, expiration data and CCV number from secured storage in step  412 . Because the process-based security server can control access to the sensitive data, the credit card numbers stored at the process-based security server cannot be compromised by hackers or malicious insiders. The credit card number, along with the expiration date and the CCV number, are sent to a financial server associated with the chosen credit card in step  414 . The financial server processes the transaction and sends a message either approving or denying the transaction to the point-of-sale server in step  416 . In some embodiments, the message may be sent to the process-based security server to be forwarded to the point-of-sale server. If the transaction has been approved, the point-of-sale server completes the transaction with the buyer in step  418 . If the transaction has been denied, the point-of-sale server informs the buyer of the denial. In either case, the process-based security server may generate a new credit card identifier in step  420 . The new credit card identifier is stored in the process-based server in association with the credit card number data and sent to the point-of-sale server to replace the old credit card identifier in step  422 . This continual refreshing of the credit card identifier limits any possible damage caused by intercepting a communication containing the credit card identifier, as the identifier ceases to be valid after one attempted use.  
         [0123]    Another use of the process-based security system is for secure file transfer. With reference to FIG. 17, a flowchart for a secure file transfer process is shown. The process allows Client A, connected to a process based security server, to securely transfer a file to Client B. Client A initiates the session with the process-based security server in step  424 . The process based security server authenticates Client A, using the authentication protocol outlined previously in step  426 . Client A then transmits a file in step  428  to the process-based security server for storage in a location that is accessible to Client A and Client B in step  430 . When Client B initiates a session in step  432 , the process-based security server authenticates the identity of Client B in step  434 . Once authenticated, Client B is then permitted to access the file stored in the location accessible to Client A and Client B in step  436 . Transmission of the file between the clients and the process-based security server is typically encrypted, using SSL or some other encryption protocol to secure the data during the network transmissions.  
         [0124]    With reference to FIG. 18, a flowchart of a boot sequence in accordance with one embodiment is shown. When the boot sequence is initiated in function block  438 , the process-based security server checks the hard drive of the process-based security server to check for a boot sector in function block  440 . Normally, the boot sector will be present on the hard drive, but in the case where a new hard drive has been installed or the boot sector of the hard drive has been damaged, there will not be a working boot sector. In the case where the hard disk is damaged but the hard disk still has a working boot sector, a function may be present to allow a user to force the device to boot off of the flash memory. If there is a boot sector detected in decision block  442 , the process follows the YES path to boot the process-based security server from the hard drive boot sector in function block. If no boot sector is detected, the process follows the NO path to function block  446  and the process-based security server boots from a flash memory. The flash memory boot causes the hard drive to be formatted in function block  448  and populates the hard drive with the process-based security software in function block  450 .  
         [0125]    A process-based security system may be used on a server in a network computing environment, on any computer or computing device, either in isolation or working as a client connected to a server. Other digital devices suitable for implementing operating system level access protection, such as laptops, hand-held computing devices, personal digital assistants (PDA), or cellular telephones, may implement process-based security.  
         [0126]    Although the illustrative embodiment has been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims.