Abstract:
A technique for providing data security through the removal of elements of a database table, be they the data fields themselves, or structural components, such as connection information that defines how, for example, the elements of a database are structured. The removed elements are placed in a secure location, retrievable only by having knowledge of a new primary key stored with the removed elements.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/496,090, filed Aug. 18, 2003. The entire teachings of the above application are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The problem of protecting an organization&#39;s sensitive data from access by unauthorized users is an increasingly important issue for essentially all businesses, government and agency organizations, as well as consumers. In response to the problem of unauthorized access, organizations often adopt a multi-layered approach to security, using some combination of perimeter systems (e.g., firewalls or authentication) and encryption technologies designed to mathematically encode data within a database. 
     Unfortunately, years of experience have demonstrated that even the most sophisticated perimeter and encryption technologies can be penetrated by determined attackers, with incidents of such vulnerabilities being both continuous and well-documented. Once such penetration occurs, unauthorized access has been gained to the actual data being protected, and the confidentiality of this data is at risk. 
     SUMMARY OF THE INVENTION 
     The present invention involves the concept of providing data security through the removal of elements of a data store, whether they be the data fields themselves or structural components, such as connection information that defines how the tables of a database are related. The removed elements are placed in a secure remote location, retrievable only by those having authenticated permission to access the removed information. 
     In the case of data element removal, individual data elements are removed from the database tables and secured via access control mechanisms. As determined by the access control mechanisms, the removed elements are then accessible only by authorized users. 
     The database structure is disassembled into discrete tables by removing the linkages that bind the database tables together and securing the linkages via access control mechanisms. The individual tables of the database structure are then stored as separate, unrelated tables on either the same, or different, computers. Then, as determined by the access control mechanisms, the linkages are retrieved and employed to reassemble data from the individual database tables for authorized users. 
     The method may involve assigning new primary keys and/or linkage fields to the table to allow for secure retrieval of the removed data elements and their association with the appropriate table data elements. 
     The invention has advantages over techniques that remove data elements but then rely simply on encryption and/or access control for security. Specifically, the present invention depends on deconstruction, removal of elements (data elements or structural elements), and inserting a new primary key. The present invention can still utilize encryption in the data tables that have elements removed or in the secure location where removed elements are stored, but the invention is not dependent on the use of such encryption to achieve data security. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
         FIG. 1  is a block diagram of a network in which the present invention may be employed; 
         FIG. 2  is a flow diagram of a process to remove and secure an element from the replicate table; 
         FIG. 3  is a flow diagram of a process to reconstruct the replicate table; 
         FIG. 4  is a diagram of the original or replicate table; 
         FIG. 5  is a diagram of the replicate table with the new primary key field; 
         FIG. 6  is a diagram of the replicate table with the new primary key field and a data field removed; 
         FIG. 7  is a diagram of the secure location where the replicate new primary key and the removed element are stored; 
         FIG. 8  is a flow diagram of a process to secure the link between replicate tables; 
         FIG. 9  is a diagram of original or replicate parent and child tables linked together; 
         FIG. 10  is a diagram of the replicate parent and child tables with new primary keys and new link fields; 
         FIG. 11  is a diagram of the parent table with the new link field removed and the child table with the link field removed; and 
         FIG. 12  is a diagram of the secure location where the removed link fields are stored. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In general, determined attackers can and will penetrate perimeter security (e.g., firewalls) and encryption technologies. Thus, sensitive data that resides in a database protected only by these techniques is potentially at risk to unauthorized access. 
       FIG. 1  shows a network in which the present invention may be employed. A user/client  110  can access a public server  120  containing database tables. An authorized user/client  110  can further access a secure server  130  via secure network connections  160 . 
     To understand a first aspect of the present invention, consider the structure of a typical relational database. In such a structure, data elements reside in rows and columns. Each row contains the potential for multiple fields, with each field in the row being a separate column. Within this structure, if data contained in a field, row, column, or table is corrupted or removed, that data is no longer available for access in the table. 
     To that end, the present invention provides security by preventing unauthorized access to sensitive data through the removal of certain elements from the database. In such an instance, even a successful attacker cannot access data that is no longer there. In addition, the removal process occurs in such a way as to enable the programmatic reconstruction of the database for authorized users. 
     Programmatic removal and relocation of a data element from a table to a separate, secure location having memory of the original location of the removed element in a database table allows for, first, security of the removed data element and, second, programmatic reconstruction of the removed data element to the database table. 
     In a first embodiment, the invention can be carried out by a data processing system that is adapted for relational database processing. Such a system may include an appropriately programmed data processor with associated secure storage  130  that is accessible via secure network connections  160 . 
     A method that secures data through element removal proceeds as a sequence of processing steps shown in the flowchart in  FIG. 2 . The method begins in step  205 . In step  210 , the original table is replicated to produce a replicate table  400  shown in  FIG. 4 . The replicate table  400  (and the original table) consists of a Primary Key  405  field and any number of fields for data such as Field Two  410 . All of the data in the replicate table (and original table) is available for retrieval. However, if the data in Field Two  410  is corrupted, such as by its complete removal, it is no longer available for retrieval and the table is of limited value to someone who accesses it. 
     To reach that result, in step  220 , a new primary key (NPK) field is added to the replicate table, with the NPK value having no relationship to the original table data (such an NPK value can be generated randomly or in other ways). The resulting table is shown in  FIG. 5  where the NPK field  510  has a value, for example, of X4S7. 
     In step  230 , a secure location is created for the storage of objects removed from the replicate table. The secure location should be separate from the originating database containing the table data to be removed, and is ideally an object oriented data environment with very strong access control attributes. An example of an object oriented database suitable for this repository would be the StrongBox™ product available from Eaglehawk Limited or the ObjectStore® product available from Progress Software. Alternatively, the secure location could be a relational or other database type, utilizing very strong access control and possibly encryption of data. 
     Next, in step  240 , the New Primary Key is replicated and stored into the secure location as an individual object.  FIG. 7  shows a secure location  700  where the NPK value  710  is stored. 
     Finally, in step  250 , (user specified) data from the replicate table is replicated, removed, and stored as objects in the secure location. For example,  FIG. 6  shows a replicate table  600  with the data from Field Two  610  removed leaving a NULL or specious value. As illustrated in  FIG. 7 , the removed data (BBBB) is stored as an object in the secure location  700 . In the end, the contents of the secure location  700  will appear as a disjointed set of values to an unauthorized user. The removed data of the replicate table is thus replicated in the secure location, ensuring that no obvious relationship exists with the NPK value to a user who does not have appropriate access rights. The original table can then be deleted or removed from user access. 
     When a user or client needs access to the replicate table data including the removed data elements the flowchart steps shown in  FIG. 3  are followed. The method begins in step  305 . In step  310 , an authorized user or client makes a reconstruction request for removed and/or table-resident data elements. Any table-resident elements are processed based on selection criteria of the request. In step  320 , NPK values of rows meeting the selection criteria are retrieved. In step  330 , the secure location is accessed using retrieved NPK values and removed data elements are located and processed according to selection criteria applying to the NPK of these data objects. Finally, in step  340 , using matching NPK values, the previously removed and table-resident data elements meeting selection criteria of the request are combined. 
     A second important aspect of the present invention relates to the fact that in a traditional relational database structure separate data tables can be, and typically are, connected using parent-child relationships. Each such table must have a primary key (PK) field. A row in each child table must have a field with a value matching the value of its parent row in the parent table PK field. For example, in  FIG. 9 , a child table  920  has a value in Field One  925  matching the value in the PK field  915  of a parent table  910 . 
     However, if the parent table PK field in such a structure is corrupted or removed, the child table is no longer able to relate to the parent table. As such, a secure method for storing the table can be provided through programmatic removal and relocation of a parent table PK to a secure location. As described above, this allows for, first, security through the inability of the child table to relate to the parent table and, second, programmatic reestablishment of the parent/child relationship. 
     In one embodiment, the invention can secure the contents of a structural table by the processing steps shown in  FIG. 8 . The process begins in step  805 . In step  810 , the original parent and child data tables are replicated producing replicate parent and child tables. In step  820 , two fields are added to each replicate table: a New Primary Key (NPK) field and a New Linking (NL) field.  FIG. 10  illustrates the addition of these new fields in the replicate parent table  910  and the replicate child table  920 . In step  830 , the NPK field in the replicate parent and child tables are populated with different values having no relationship to the original data. For example, in  FIG. 10 , the NPK field  1030  of the child table  920  has a different value than the value of the NPK field  1010  of the parent table  910 . 
     In step  840 , the NL field in the parent and child replicate tables are populated with the same values, but again, having no relationship to the original data. For example, in  FIG. 10 , the NL field  1040  of the child table  920  has the same value as the NL field  1020  of its parent row in the parent table  910 . 
     In step  850 , the NPK field value from the Parent Table is replicated and stored in a secure location. 
     In the remaining steps the data structure is secured by disconnecting the replicate parent and child tables. First, in step  860 , the replicate parent table NL field is removed, secured in a secure location, and set to NULL. Then, in step  870 , the replicate child table field matching the replicate parent table PK is set to NULL. 
     At the end of this process, the replicate parent and child tables appear as they do in  FIG. 11  with the NL field  1020  in the Parent Table  910  set to NULL and Field One  925  in the Child Table  920  set to NULL.  FIG. 12  illustrates the secure location  1200  at this point containing the replicate NPK value of the Parent Table  1220  and the NL field value of the replicate parent and child tables  1210 . 
     The data structure is then reestablished by reconstructing the parent/child relationship. A method of the secure location when supplied with the replicate parent table NPK will return the replicate child table NL, thus providing the ability to reestablish the relationship between tables. Similarly, a method of the secure location when supplied with the child table NL will return the replicate parent table NPK, thus providing the ability to reestablish the relationship between tables. 
     While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.