Abstract:
A method and apparatus for remote logging of access to and activity on a computerized network is provided. Logging information is transmitted to a remote log repository and is not maintained by the local log generating machine. After the logging information is stored in the remote repository, the access to the information is controlled by a specific policy that governs the type of information and the time period during which the information is available. No access is provided to information outside the bounds of the access policy. Preferably the remote log repository is outside the jurisdiction of relevant authorities. This allows the access policy between the log generating entity and the log repository to dictate precisely the information that is under the control of the log generating entity. The use of a remote log repository and a specific access policy affords flexibility to the log generating entity in balancing its multiple responsibilities and makes responding to subpoenas cost effective and efficient.

Description:
RELATED APPLICATIONS 
     This application is related to co-pending application Ser. No. 11/426,687, entitled “Endpoint Activity Logging” and co-pending application Ser. No. 11/426,699, entitled “Unique Identifier Validation,” both of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     This invention relates to the field of network monitoring, and more particularly to the logging of access to and/or activity on a computerized network such as the Internet. 
     BACKGROUND 
     It is a usual practice for companies providing access to the Internet and for companies providing content and services on the Internet to generate logs of access and activity. Some examples of how logs are used are: for debugging and troubleshooting, detection and monitoring of abuse, statistical analysis, demographic analysis, report generation and other general business purposes. 
     One issue that arises with the storage of access and activity logs is the convenient and efficient maintenance of those logs. Entities that provide access to the Internet, and entities that make content and services available on the Internet, often have the triple responsibilities of (1) maintaining privacy, (2) maintaining the integrity of the services being provided, and (3) complying with all applicable laws regarding the disclosure of information. To fulfill the responsibility of maintaining privacy, the entity would ideally log as little information as possible. Any information maintained represents a liability to the entity generating the information in this regard since it represents a risk of disclosure and possible compromise of privacy. 
     To fulfill the second responsibility of maintaining the integrity of the services being provided, the entity needs to log certain types of information for certain periods of time. For example, enough information should be maintained long enough so that abuse can reasonably be detected over a reasonable period of time. Additionally, billing requirements may require certain information be maintained. This responsibility does not necessarily mean complete logs must be maintained. In certain cases, the entity only needs summary information, and/or only needs to maintain the information for a limited period of time. For example, an entity proving access to the Internet may want to maintain for over a year the number of minutes connected on a certain day, while the specific IP address in use on that day and the specific port numbers used may only be needed for days or weeks. 
     The third responsibility is to comply with all applicable laws for the jurisdiction under which the entity operates. In some cases, there are no laws that require the preservation of logging information, in which case the logged information would be governed by other concerns. In other cases regulations may require that certain types of information may be maintained for a specific period of time. Another type of legal responsibility that arises in certain circumstances is not a requirement a priori that certain information be maintained, but that all information that is under the custody or control of the entity is produced at the time a subpoena is received. Since responding to subpoenas is expensive and time consuming, it is most efficient to maintain custody and control only of that information that is required for business reasons or legal reasons. 
     Thus, it can be seen that there is a balance in what information is logged, how it is accessed and for how long it is maintained. In many cases merely maintaining complete logs indefinitely is not an efficient or appropriate mechanism for maintaining these multiple responsibilities. What is needed is an improved method of maintaining and accessing logs that allows log generating entities to more cost effectively balance their multiple responsibilities. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a method and apparatus for remote logging of access to and activity on a computerized network. Logging information is transmitted to a remote log repository and is not maintained by the local log generating machine. After the logging information is stored in the remote repository, the access to the information is controlled by a specific policy that governs the type of information and the time period during which the information is available. No access is provided to information outside the bounds of the access policy. Preferably the remote log repository is outside the jurisdiction of relevant authorities. This allows the access policy between the log generating entity and the log repository to dictate precisely the information that is under the control of the log generating entity. The use of a remote log repository and a specific access policy affords flexibility to the log generating entity in balancing its multiple responsibilities and makes responding to subpoenas cost effective and efficient. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a prior art interconnection and logging mechanism. 
         FIG. 2  illustrates a prior art interconnection and logging mechanism. 
         FIG. 3  illustrates activity logging in an embodiment of the present invention. 
         FIG. 4  illustrates communication and logging events in an embodiment of the present invention. 
         FIG. 5  illustrates activity logging in an embodiment of the present invention. 
         FIG. 6  illustrates MAC address registration and validation. 
         FIG. 7A  illustrates remote logging across a jurisdictional boundary. 
         FIG. 7B  illustrates remote access to log information across a jurisdictional boundary. 
         FIG. 8A  illustrates encryption and decryption management for remote logging and reporting. 
         FIG. 8B  illustrates an alternative embodiment of encryption and decryption management for remote logging and reporting. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a typical environment in which a Web Server on the Internet logs activity. User  110  represents a user operating a browser and connected to the Internet  120 . Web Server  130  is a web server connected to the Internet  120  and storing web pages for public viewing. When User  110 , through the browser running on their computer, requests a web page stored on Web Server  130 , a HTML document is delivered to the browser and displayed to User  110 . In addition, a record is made of this activity in Access Log  140 . A web server activity log will typically contain information regarding the access, but not the actual content of the access itself. For example, a web server log generally records the originating IP address, the name of the document that was requested and the number of bytes that were transferred to the client machine. It is common to record in an access log file a record of each access. 
     The Apache Software Foundation is an organization that supports an open-source web server known as Apache HTTP Server Project. Documentation and software for the Apache HTTP Server Project are located at http://httpd.apache.org. The Apache web site indicates that Apache has been the most popular web server on the Internet since April 1996, and as of 2005 represents more than 70% of the web sites on the Internet. The document entitled “Log Files” available on the Apache web site at: http://httpd.apache.org/docs/2.2/logs.html, incorporated herein by reference, describes several log file formats. Log file formats in use today, such as those described in the document referenced above, record the originating IP address of each machine that requests a document. 
     In cases such as  FIG. 1  in which User  110  is directly connected to the Internet  120 , the originating IP address is sufficient to identify the machine at which the request originated. However this is not the case in other scenarios.  FIG. 2  illustrates a more common situation in which User Computer  210  is located on Local Network  220  behind NAT Gateway  230 . Typically the IP addresses in use on Local Network  230  are unregistered or un-routable addresses that can be used within an enterprise but cannot be used on the public Internet. Un-routable addresses are addresses that have been set aside in the ranges 10.0.0.0 to 10.255.255.255, 172.16.0.0 to 172.31.255.255 and 192.168.0.0 to 192.168.255.255. IP addresses in this range may be freely used within a private network as they are guaranteed to be unused and unusable on the public Internet. NAT Gateways are used to convert packets coming from un-routable IP addresses into packets with addresses valid on the public Internet. This scheme is utilized to allow many machines to be used on an internal network without tying up as many public IP addresses, which are global resources. 
     In particular, NAT Gateway  230  operates a function known as Network Address Translation (NAT), which translates internal network addresses into external network addresses. Thus, a packet originating from User Computer  210  is translated by NAT Gateway  230  into another packet with a different source IP address and transmitted to Web Server  260  across the Internet  250 . A return packet from Web Server  250  to User  210  will be transmitted to NAT Gateway  230 , which will translate the packet into a different packet with the destination IP address for User Computer  210 . The operation of NAT Gateways on the Internet is well known and in wide use today. 
     Frequently internal networks allocate IP addresses using a protocol known as DHCP. This requires the use of a DHCP Server  240  attached to Local Network  220 . Briefly, the DHCP protocol involves the allocation of IP address upon request by machines on the local network. For example, when User Computer  210  powers up, it will request an IP address and DHCP Server  220  will allocate one. This operation is known as a “lease” and generally has an expiration time associated with it. The DHCP protocol generally requires periodic communication between User Computer  210  and DHCP Server  240  in order for User  210  to continue to be allowed to use the IP address to which it has been granted. 
     Many machines may exist on Local Network  220 , and there may be multiple NAT Gateways within a large enterprise. This means that a request for a document on the Internet originating from a browser on a user&#39;s machine may be translated multiple times before it reaches the web server that is hosting the document. Thus, Access Log  270  that is recorded by Web Server  260  is insufficient to identify the specific machine that actually made the request. 
       FIG. 3  illustrates activity logging in an embodiment of the present invention. User Computer  310  is connected to Local Network  320  which is connected to NAT Gateway  330  and DHCP Server  340 . In most embodiments, NAT Gateway  330  and DHCP Server  340  will be implemented on the same physical machine and there will only be one network connection from that machine to Local Network  320 . NAT Gateway  330  is coupled to the Internet  350 , which is in turn coupled to Web Server  360 . Access Log  370  receives information from Web Server  360 , NAT Gateway  330  and DHCP Server  340 . By combining information from all three sources as described in more detail below, activity logs can be generated that uniquely associate User Computer  310  with activity on Web Server  360 . 
     Access Log  370  is shown in  FIG. 3  as a single unit for illustrative purposes. The storage of activity data can be distributed across multiple machines and the physical location or locations of the log storage can vary. Web Server  360 , NAT Gateway  330  and DHCP Server  340  can locally store activity information and then periodically transfer it to a central location, or in alternative embodiments the activity information may be transmitted immediately to a central repository. In still other embodiments, the activity information may never be stored together in one physical location but may be maintained separately and controlled by separate entitles. It will be appreciated to those of skill in the art that as long as the requisite information is recorded in some fashion, there are many alternatives to how, when and where the information is stored. 
     One feature of an embodiment of the present invention is that Web server activity can be associated with an individual user and/or an individual computer, through for example a MAC address. Every computer having an Ethernet interface in principle has a globally unique MAC address, which is a 48-bit address associated with the Ethernet interface and used as the source address for Ethernet frames transmitted from that interface. The MAC address is created by the manufacturer at the time the interface is created. Alternative identifiers can be used to uniquely identify a particular user or computer. For example, some central processing units (CPUs) have unique processor IDs that are created by the microprocessor manufacturer and are globally unique and cannot be changed by the user. 
     It will be appreciated to those of skill in the art that other forms of unique identifiers can be used, including a phone number, address, bank account number, credit card number, social security number, license plate number, or the like. It is also the case that the identifier need not uniquely identify the user or computer throughout the entire world. In certain embodiments it may only be necessary to identify the user or computer within a certain group or it may only be necessary to narrow down the user or computer into a relatively small group. 
     In order to associate the MAC address used by User Computer  310  with activity that occurs on Web Server  360 , it is desirable to record the association between the MAC address used by User Computer  310  and an IP address allocated by DHCP server  340 . Additionally, it is desirable to record the alias link between an internal and external IP address that is created by NAT Gateway  330 . This is explained in more detail below. 
       FIG. 4  illustrates communication and logging events in an embodiment of the present invention. User Computer  410  exchanges messages with DHCP/NAT Gateway  420 , which in turn is coupled to Remote Server  430 .  FIG. 4  illustrates the types of information that are logged in an embodiment of the present invention in order to associate User Computer  410  with remote activity. When User Computer  410  is first connected to a local network on which DHCP/NAT Gateway  420  is also connected, it communicates with DHCP/NAT Gateway  420  in order to get an IP address to use. The DHCP protocol is typically used to perform this function, although there are alternative dynamic IP address allocation protocols that can be used. When a dynamic IP address is allocated to User Computer  410 , this is known as a “lease” and will typically last for a defined period of time at which point it needs to be renewed through further exchange of messages. 
       FIG. 4  illustrates a simplified exchange of DHCP messages between User Computer  410  and DHCP/NAT Gateway  420  for illustrative purposes. Those of skill in the art will appreciate that the DHCP protocol involves other messages. In the example of  FIG. 4 , first User Computer  410 , using the MAC address 00:10:c6:cf:94:c6 requests an IP address from DHCP/NAT Gateway  420 . Next, DHCP/NAT Gateway  420  allocates dynamic IP address 192.168.0.11 to User Computer  410  and sends an acknowledgement message to User Computer  410  with this information. At this point, the lease of IP address 192.168.0.11 to MAC address 00:10:c6:cf:94:c6, illustrated by information block  440 , is recorded. An actual sequence of DHCP messages that represents this exchange is typified by the following: 
     User→Server: DHCPDISCOVER from 00:10:c6:cf:94:c6 
     Server→User: DHCPOFFER on 192.168.0.11 to 00:10:c6:cf:94:c6 
     User→Server: DHCPREQUEST for 192.168.0.11 from 00:10:c6:cf:94:c6 
     Server→User: DHCPACK on 192.168.0.11 to 00:10:c6:cf:94:c6 
     The establishment of a “lease” represents the grant of an IP address to a particular machine identified by an Ethernet address. In this case the IP address granted is an internal, un-routable address, which can be used on a local network but cannot be used on the Internet. DHCP servers can typically be configured to allocate either internal or external IP addresses, and can allocate from a pool of IP addresses, or can be configured to associate particular IP addresses with particular MAC addresses. 
     An example of software that performs the DHCP functionality is the dhcpd daemon (a daemon is a computer program that runs in the background) that is a standard utility on may Unix systems. The dhcpd daemon is configured to listen on certain interfaces and to respond to broadcast messages from machines requesting IP addresses. Some implementations of dhcpd can be configured to automatically log the granting of leases and the expiration of leases. In one embodiment of the present invention, the dhcpd daemon is configured to generate this information, and/or is modified to transmit this information to another host, immediately or periodically. 
     The next sequence illustrated in  FIG. 4  relates to network address translation (NAT). Because User Computer  410  is utilizing an un-routable IP address, this address needs to be translated to an external IP address before packets can be sent over the Internet. This is the job of the NAT gateway. The establishment of an association between an internal IP address and port number to an external IP address and port number is known as an “alias link.” Because there may be many internal machines communicating with the same remote host, it may be necessary for the NAT gateway to change the port number from the one utilized by User Computer  410 . Because TCP connections are uniquely identified by source and destination IP address and source and destination port numbers, multiple connections from the same IP address can be established to the same destination port number as long as the source port number is different for each connection. 
     In the example illustrated in  FIG. 4 , User Computer  410  sends a packet to set up a connection to a remote Web server at IP address 66.102.7.104, port 80. The source IP address for User Computer  410  is 192.168.0.11 and the source port number is 1534. Upon receiving the packet from User Computer  410 , DHCP/NAT Gateway  420  establishes an alias link, rewrites the outgoing packet and sends it to the Internet. Because the un-routable address used by User Computer  410  is not usable on the Internet, the source address for the outgoing packet is replaced with the source address for DHCP/NAT Gateway  420 , which in this example is 63.198.33.202.  FIG. 4  illustrates that DHCP/NAT Gateway  420  associated port 3541 with User Computer  410  source port 1541. At this point the alias of source IP address 192.168.0.11 to external IP address 63.198.33.202, port 3541 is recorded, as illustrated by information block  450 . 
     An example of software that performs NAT functionality is the natd daemon that is a standard utility in many Unix systems. In some implementations natd relies on a library known as libalias which performs the function of maintaining a table or database of IP number and port number associations. The libalias library code adds and deletes alias links as needed. In one embodiment of the present invention, the libalias library is modified to log certain alias links to a file and/or to transmit this information to another host, immediately or periodically. 
     The next sequence illustrated in  FIG. 4  is the receipt of the packet by Remote Server  430  and the return of a packet to DHCP/NAT Gateway  420 , which subsequently returns a packet to User Computer  410 . Remote Server  430  could be a Web Server, an Email Server or any other server on the Internet for which activity logging is desired. In the example shown in  FIG. 4 , Remote Server  430 , which is at IP address 66.102.7.104 receives a packet to port 80 from source IP address 63.198.33.202, port 3541. Remote Server logs the access as illustrated in information block  460 . 
     Web server logging is well known the field and it is common for Web servers to log activity. A typical log entry consists of the source IP address and the document requested along with other information. The Apache HTTP Server, described above, defines a “Combined Log Format” that can be utilized to configure the Web server for what information is logged. An example entry in the Combined Log Format is shown below:
         127.0.0.1-frank [10/Oct/2000:13:55:36-0700] “GET/apache_pb.gif HTTP/1.0”200 2326 “http://www.example.com/start.html” “Mozilla/4.08 [en] (Win98; I; Nav)”       

     The fields in this entry are as follows: 127.0.0.1 is the IP address of the client that made the request of the Web server, the dash is a null field in place of the RFC 1413 identity of the client, frank is the user ID of the person requesting the document as determined by HTTP authentication, the date field between brackets is the date and time that the request was received, the next field between quotes is the request that was received from the remote host, 200 is the status code that the Web server sent back to the client, 2326 is the size of the object returned to the client in number of bytes, the next field between quotes is the site that the client reports having been referred from, and the last field between quotes is the identifying information that the client browser reports about itself. 
     Note that a Combined Log Format entry such as illustrated above is not in general sufficient to uniquely identify an individual user. In particular, the source port number is not typically logged. Because many clients may be connecting to the Internet behind a single NAT gateway, in many circumstances the only way to distinguish an individual user it to log the source port number of the HTTP request. In a preferred embodiment of the present invention, the Web server software running on Remote Server  430  is modified to log the source port number of each HTTP request in addition to other information, and to send this information to a log file, and/or to transmit this information to another host, immediately or periodically. When the source IP address and source port number are correlated with the alias link information and with the IP to MAC address association, it is possible to associate a particular user with activity that occurs on a remote server. 
     Another form of Remote Server is an email server. A typical email transmission from a user to a recipient on the Internet involves a user&#39;s computer contacting a local SMTP relay on port 25, sending the email and closing the connection. Subsequently the local SMTP relay consults the DNS (domain name system) to determine the appropriate remote email relay for the domain name of each recipient of the email. If properly configured, the DNS zone for the destination domain will contain an “MX Record” which will specify the machine or machines on the Internet who will accept email for that domain. The local SMTP relay then contacts one of the machines indicated in the MX Record on port 25 and delivers the email message. Many if not most SMTP relays are configured to generate logs of sent and received email messages. The format of a log entry depends on the software used and the version of that software. A format for sendmail which is a software program that performs SMTP relay functions and is a standard component of many UNIX systems is shown below:
         &lt;date&gt;&lt;host&gt;sendmail[pid]: &lt;qid&gt;: &lt;what&gt;=&lt;value&gt;, . . .       

     Included in each log entry is a date stamp, the name of the host generating the information, the process ID for the running process, a queue ID and a comma separated list of parameter/value pairs. One of the parameter/value pairs commonly logged is the name and IP address of the remote host the email is being received from or is being sent to. For example, an entry in a log file might contain the following parameter/value pair: “relay=floozy.zytek.com.[63.198.33.206]” indicating that email was received from the IP address 63.198.33.206, having the name floozy.zytek.com. 
     In some cases it may not be important to log more that just the IP address of the machine sending an email, since email relays typically receive email directly from other email relays, or from trusted users. However, for the same reasons noted above for Web servers, this information is not in general sufficient to specifically identify an individual computer. In particular, the source port number is not typically logged. Because many clients may be connecting to the Internet behind a single NAT gateway, in many circumstances the only way to distinguish an individual computer it to log the source port number of the incoming SMTP connection. In a preferred embodiment of the present invention, the sendmail software running on Remote Server  430  is modified to log the source port number of each incoming SMTP connection in addition to other information, and to send this information to a log file, and/or to transmit this information to another host, immediately or periodically. When the source IP address and source port number are correlated with the alias link information and with the IP to MAC address association, it is possible to associate a particular computer with activity that occurs on a remote server. 
     In certain embodiments of the present invention, it may not be necessary to record the IP to MAC address association at the time the lease is generated by the DHCP Server. Instead, this information may potentially be generated at the same time the alias information is generated. This is because the packet that is received by the DHCP/NAT Gateway  420  may contain the source Ethernet address of User Computer  410 . In this case, DHCP/NAT Gateway  420  can just look at the source Ethernet address and record this as the MAC address associated with the source IP address that is also in the packet. In this case, the information contained in information block  440  and the information contained in information block  450  are combined into a single entry created at the same time by DHCP/NAT Gateway  420 . However this implementation is not always possible because in some embodiments, the source Ethernet address of the packet received by DHCP/NAT Gateway  420  is not the original source Ethernet address of User Computer  410 . This could be the case if there are intervening routers or other devices between User Computer  410  and DHCP/NAT Gateway  420 . There may also be situations, as discussed below, where multiple NAT gateways are employed between the user originating a packet and the machine that is ultimately responsible for delivering that packet to the Internet. 
       FIG. 5  illustrates activity logging in an alternative embodiment of the present invention. User Computer  510  is connected to Wireless Local Network  520  which is connected to NAT Gateway  530  and DHCP Server  540 . In most embodiments, NAT Gateway  530  and DHCP Server  540  will be implemented on the same physical machine and there will only be one wireless network connection from that machine to Wireless Local Network  520 . NAT Gateway  530  is connected to Wired Local Network  550 , which is in turn connected to NAT Gateway  560 . NAT Gateway  560  is coupled to the Internet  570 , which is in turn coupled to Web Server  580 . Access Log  590  receives information from Web Server  560 , NAT Gateway  560 , NAT Gateway  530  and DHCP Server  540 . By combining information from all four sources as described in more detail below, activity logs can be generated that uniquely associate User Computer  510  with activity on Web Server  580 . 
     The interconnection illustrated in  FIG. 5  is more complicated than the interconnection illustrated in  FIG. 3  because packets from User Computer  510  go through two NAT Gateways before reaching the Internet. This means that a first un-routable address may be used on Wireless Local Network  520 , these packets may be translated into packets utilizing a second un-routable address and sent between NAT Gateway  530  and NAT Gateway  560 . Finally, NAT Gateway  560  translates the packets from the second un-routable address to an external IP address for use on the Internet. Traceability back to User Computer  510  requires that the association between the user and the first un-routable IP address be recorded, that the alias link between the first and second un-routable addresses be recorded and that the alias link between the second un-routable address and the external IP address use by NAT Gateway  560  be recorded. The process of logging information in the interconnection of  FIG. 5  is similar to that described above in connection with  FIG. 3  and  FIG. 4  with the addition of a second NAT Gateway. 
     As explained above, it may be possible for NAT Gateway  530  to record the alias link information as well as the MAC address to IP address association since it receives packets directly from User Computer  510 . In this case, only two sources of information, NAT Gateway  530  and NAT Gateway  560  are needed to associate User Computer  510  with packets being transmitted on the Internet. 
     As explained above in connection with  FIG. 3 , Access Log  590  is shown as a single repository for illustrative purposes. The repository may be distributed and the correlation of the multiple pieces of information necessary to establish the identity of activity need not be actually performed until needed. For example, since the activity known to Web Server  580  is under the control of the entity operating the Web site or sites associated with Web Server  580 , it may be stored separately from the other information. Similarly, the access information known to the NAT gateways and the DHCP servers are typically under the control of the entity who provides access of the user to the Internet, which may be a different entity form that operating Web Server  580 . 
     In some cases, it may be sufficient that the information necessary to correlate a specific user with specific Internet activity is available if and when necessary. Thus, the actual correlation is not performed unless required. It may be the case that the entity providing access of a user to the Internet protects the alias link and IP lease information unless required to provide it by a Court or law enforcement official, or dictated by an internal investigation. In some cases the entity providing access of a user to the Internet may be required to preserve the alias link and IP lease information, either by laws governing the entity in whatever jurisdiction they operate, or by contract dictated by the Internet service provider they connect through. 
     One issue that can arise when logging MAC address to IP address associations, such as through a DHCP lease or other address allocation mechanism, is the validity of the MAC address or other identifying information that is utilized by the user. Some Ethernet interfaces can be re-programmed by the user to set the MAC address to an arbitrary value not set by the manufacturer. This facility would allow the user to masquerade as an arbitrary MAC address, which in some cases would defeat the purpose of uniquely identifying the machine and/or user that is connected. For example, a user wishing to remain completely anonymous could configure User Computer  510  to utilize an arbitrary MAC address and connect to Wireless Local Network  520 , and subsequently to the Internet  570 . The same is true of any ID number used to identify the user if the number can be selected arbitrarily by the user. One way to address this issue is to require identifying information to be validated. 
     In some cases of public access to the Internet, user authentication takes place at the application level where users must type in user names and passwords. In such a case, it can be relatively simple to associate MAC addresses in use and/or allocated IP addresses with individual users. In this case, the related user account can be logged along with the other access information, allowing for possible later association to an individual. In this case, it may not be necessary to validate the MAC address in use, since the user is being identified through other means. In cases where there is no explicit user identification, or where it is important to further validate the access information, identification validation can be performed. Identification validation is one aspect of an embodiment of the present invention and is described below. 
     The purpose of identification validation is to guarantee that an association can be made between access to and/or activity on a local or wide-area network such as the Internet and an individual user, location, piece of equipment, etc. There is usually a tradeoff between security and privacy in such circumstances. While the anonymity of certain types of access and activity on the Internet is desirable and important, for other types of access and activity, it is also desirable and important that individuals responsible can be identified. The use of a carefully designed identification authentication system can appropriately balance these competing concerns. For example, information sufficient to identify access or activity can be maintained, while safeguards can be put in place to ensure that only in specific cases (such as a Court Order or Subpoena) would the information be made available. In another example, this information could be placed in the hands of an independent third party, who would provide the information under specific guidelines. 
       FIG. 6  illustrates MAC address registration and validation. MAC Address Registrar  600  is responsible for receiving a MAC address  610  and producing a signed version of the MAC address  615 . MAC Address Validator  650  is responsible for receiving an encrypted and signed MAC address  680  and validating the MAC address to generate a validation status  690 . The registration/validation process of the present invention is based on the use of public key cryptography. Public key cryptography is based on a matched pair of keys, one used to encode information and one used to decode information. By keeping one of the matched keys private and making the other public, the functions of authentication and encryption can be realized. 
     MAC Address Registrar  600  receives a MAC address  610  and signs it at  620  and produces a signed MAC address  615 . The Sign function  620  utilizes a Private Key  625  of MAC Address Registrar  600 . The use of a private key accomplishes the function of authentication since one can verify using Public Key  630  that the signed MAC address was produced by MAC Address Registrar  600 . The mathematics of the matched key pairs make it computationally infeasible to generate Private Key  625  knowing only Public Key  630 . Thus, it is impractical to generate a signed MAC address  615  without access to Private Key  625 . This means that Private Key  625  should be maintained in confidence by MAC Address Registrar  600 . There need not be a single MAC Address Registrar, but in embodiments of the present invention there may be many. Indeed any entity responsible for granting access to the Internet may chose to maintain a separate MAC Address Registrar. 
     An Ethernet MAC address is 48-bits in length. The purpose of a MAC Address Registrar  600  is to associate a MAC address with a known user, and potentially to verify the MAC address based on other criteria. This may be done, for example, by referring to the manufacturer and model of the hardware in use, by consulting a database of known MAC addressees, or by consulting a database of registered MAC addresses. Once the MAC address provided to the Registrar is verified, a signed version of the MAC address is generated. Because an arbitrary MAC address is usable to someone who can reprogram their Ethernet adapter, any signed MAC address would be usable to someone wishing to bypass the MAC address registration process. This means that it is desirable for MAC Address Registrar  600  to utilize enough bits in its signature so that it is impractical to guess signed MAC addresses even for arbitrary MAC addresses. The analysis needed to determine the number of bits needed to guarantee a certain level of impracticality based on available computational resources is known to those of skill in the art. 
     User  640  is responsible for delivering MAC Address  610  to MAC Address Registrar  600  and for saving the signed version of the MAC Address  615 . Preferably the transmission of the signed MAC Address  615  occurs over a secure channel. This is because if someone eavesdrops on this process, they could masquerade as User  640  by utilizing the MAC Address and signed MAC Address. A variety of techniques are possible to secure the transmission of signed MAC Address  615  to User  640 . In some embodiments, this process may occur over a private network. MAC Address Registrar  600  may be operated by an equipment manufacturer, distributor or reseller and may register MAC Address  610  before delivering it to a user. In other embodiments, an HTTP SSL connection is utilized to transfer Signed MAC Address  615  over an encrypted connection between MAC Address Registrar  600  and User  640 . It is appreciated by those of skill in the art that there are a variety of other techniques to securely transfer the Signed MAC Address  615  across a public network. Once Signed MAC Address  615  is delivered to User  640 , it is ideally stored in a manner inaccessible to unauthorized software running on the user&#39;s machine. This is needed to prevent malware running on the user&#39;s computer from retrieving the signed MAC address so that it could masquerade as the user. There are a variety of ways to accomplish this secure storage, including the use of passwords and additional encryption. In an alternative embodiment, Signed MAC Address  615  is stored internal to an embedded microcontroller, such as on a smart card or within an Ethernet adapter. In this case, once the embedded system is programmed with the signed MAC address, the address cannot be retrieved through an analysis of software and storage on the user&#39;s computer. 
     The validation process depicted in  FIG. 6  begins with the use of a Public Key  670  of MAC Address Validator  660  delivered to User  640  at input  650 . The use of public key encryption during the validation process guarantees that the Signed MAC Address  615  is not intercepted by an eavesdropper. This would allow such an eavesdropper to masquerade as User  640 . In one embodiment, Public Key  670  is delivered over a secure channel to User  640 . This is desirable to avoid a Man-In-The-Middle attack, in which an intermediary intercepts Public Key  670  and replaces it with their own public key. In some embodiments, Public Key  670  is delivered to User  640  at the same time as Signed MAC Address  615  by MAC Address Registrar  600 . This may be convenient in situations where MAC Address Registrar  600  is operated by the same entity that operates MAC Address Validator  660 . In this case, Public Key  670  could be stored in the same manner as Signed MAC Address  615 , including on a smart card if such a facility is used. In another embodiment, Public Key  670  is signed by a known Certificate Authority, the public key for which is previously known to User  640 . In this manner, User  640  can verify that the public key being input at  650  is indeed the public key for MAC Address Validator  660 . Those of skill in the art will appreciate that there are alternative mechanisms to deliver a public key to User  640  and to authenticate MAC Address Validator  660 . In order to protect the confidentiality of Signed MAC Address  615 , it is important to ensure that User  640  only encrypts it with keys from entities authorized to receive it. 
     In order to prevent a “replay” attack, in which an eavesdropper listens to the transmission of an encrypted signed MAC address, it is useful to combine the signed MAC address with a number used once or “nonce.” An example of nonce is a time stamp of sufficient length and granularity. Another possible implementation would be for MAC Address Validator  660  to generate a random number internally and send it to User  640  for combination with the signed MAC address. When MAC Address Validator receives the encrypted and signed MAC address at  680 , decryption and authentication is performed in box  665  using Private Key  675  and Public Key  630 , received at input  655 , and a validation status  690  is produced. MAC Address Validator  660  utilizes Public Key  630  of MAC Address Registrar to authenticate the MAC Address. In a preferred embodiment, the delivery of Public Key  630  to MAC Address Validator  660  occurs on a secure channel, to prevent an attack in which a signed MAC address is faked according to keys not belonging to MAC Address Registrar  600 . In some embodiments, MAC Address Registrar and MAC Address Validator are co-located and operated by the same entity. 
     The above description has been with regard to MAC addresses, but it equally applies to any form of identification that can be represented in digital form. The functions described with respect to User  640  can be performed by hardware or software or any combination. These functions may be implemented by software running on a user&#39;s computer, workstation, portable hand-held computer or cell phone. The functions may also be performed by dedicated hardware and firmware, such as in a smart card. In some embodiments, some or all of the functionality described in connection with User  640  is built into a network interface card by the manufacturer and transparent to the user. For example, an Ethernet card could be pre-registered with Signed MAC Address  615  and Public Key  670  could be pre-installed. In order to validate, the Ethernet card merely encrypts the signed MAC address with a timestamp and makes it available to higher level software, which can then include this number during DHCP registration. In this case the validation of the MAC address is completely transparent to the user and would not affect implementations that do not rely on this feature. In some embodiments the encrypted and signed MAC address could be made part of the DHCP protocol, in which case the DHCP server could be modified to communicate with MAC Address Validator  660  before granting an IP address lease. 
     In an alternative embodiment, a different protocol could be used after an IP address lease but before packets are accepted by the NAT gateway. For example, an encrypted and signed MAC address could be sent to a machine on the local network on which it is installed, or the NAT gateway responsible for that network could accept the encrypted and signed MAC address and communicate with MAC Address Validator  660  before granting the opportunity to forward other packets. 
     In other embodiments, a user may carry a portable smart card that can be used for authentication for use with any computer. In this case the actual MAC address used by the computer is not used for user authentication, but instead other identifying information that has been previously registered. 
     In the embodiments of the present invention discussed in connection with  FIGS. 3 ,  4  and  5  above, it was illustrated how logging information can be generated sufficient to allow individual computers to be identified. The discussion in connection with  FIG. 6  illustrates how computer or user identification can be validated. In one embodiment, the validation status  690  generated by MAC Address Validator  660  is logged along with the lease information such as that contained in information block  440 . A DHCP server, or other entity responsible to associating MAC addresses with IP addresses, could be modified to require additional information from a client computer and validate that the MAC address in use has been properly registered. Note that NAT/DHCP Gateway  420  need not know anything about the user or have access to the registration information, but merely needs to know from MAC Address Validator  660  that the MAC address in use by Client Computer  410  is valid. In this case, Validation Status  690  is merely an affirmative result transmitted to a DHCP Server or NAT Gateway. DHCP/NAT Gateway could then log an authorization code or an authentication string to prove that validation had been performed. In other embodiments, identification validation is done at the time an alias link is created and logged in connection with information such as that contained in information block  450 . 
     As noted above, there is a balance in what information is logged, how it is accessed and for how long it is maintained. It most cost effective for an entity that generates logging information to carefully design a system that appreciates the conflicting goals and responsibilities. Because merely maintaining complete logs is often not an efficient or appropriate mechanism, it may be desirable to have a remote log repository that is outside the direct control of entity that generated the logs and is outside the jurisdiction of entities that may require disclosure of information. 
       FIG. 7A  illustrates an embodiment of a remote log repository. Access logs, such as those described above are generated by Firewall/Gateway  710  and delivered across secure connection  725  to Log Repository  735 . Similarly Web Server  715  generates Web activity logs and Mail Server  720  generates email activity logs and delivers them across Secure Connection  725  to Log Repository  735 . In certain embodiments of the present invention, Log Repository is across Jurisdictional Boundary  730  from the machines that generated the logs. Logging information may or may not be combined, and may involve only one type of information, for example, just access logs from Firewall/Gateway  710  or just activity logs from Web Server  715 . Logging information may be encrypted for transport across Secure Connection  725  and may be further encrypted for storage at Log Repository  735  as described in more detail below. Logging information is also preferably compressed before being encrypted. Logging information is typically highly compressible, resulting in savings in transmission bandwidth. 
     The transmission of information from Firewall/Gateway  710 , Web Server  715  and/or Mail Server  720  to Log Repository  735  may be immediate or periodic. For example, information may be compressed hourly or daily and transmitted to Log Repository  735 . In a preferred embodiment, there is no local permanent storage of log information by Firewall/Gateway  710 , Web Server  715  or Mail Server  720 , or alternatively any permanent storage of such data is periodically deleted. The strict adherence to this policy allows the entity operating the log generating computers to establish that all of the information associated with access or activity is stored in Log Repository  735 . In other embodiments, this is not critical and the log generating computers may store the logs locally in addition to transmitting them to Log Repository  735 . 
       FIG. 7B  illustrates access to Log Repository  755  by Data Access Client  740  across Secure Connection  745 . In some embodiments, Account Data  760 , which records information such as MAC Address Registration information or other information associated with users or accounts, is stored along with Log Repository  755 . In certain embodiments of the present invention, Log Repository  755  and Account Data  760  are stored across Jurisdictional Boundary  750  from the machines that access the information. Data Access Client  740  and the communication between Data Access Client  740  and Log Repository  755  and Account Data  760  are carefully designed to satisfy the needs of the entities involved. In some cases, Log Repository  755  stores raw log information but Data Access Client only has access to summary information. In other cases, logged information may be summarized before it is stored in Log Repository  755 . In still other cases, logged information may be maintained in complete form for a certain period of time, and then summarized for further storage for a second period of time. The method of accessing Log Repository  755  by Data Access Client  740  can also be designed such that after a certain period of time, information is no longer available. This feature removes the burden from the log generating entity to delete previously stored information. This means that in cases where information is requested (e.g. via subpoena) that is outside the bounds of the access policy that has been specifically provided to Data Access Client  740 , it becomes trivial for the log generating entity to prove that it has no responsive documents. Thus, by carefully designing the data access policy, an entity generating log information can achieve an optimal and most cost effective balance between having access to information needed for business purposes and complying with all applicable laws. 
     In order to provide for the protection of information stored in a remote log repository, a variety of flexible encryption options are possible.  FIG. 8A  illustrates an encryption scenario in which Key Manger  825  generates a matched Encode Key  815  and Decode Key  830 , using techniques such as are well known in the field of public key cryptography. Server  805  generates logging information, encoding of that information takes place in Box  810 , and the encoded information is stored in Repository  820 . The encoding process  810  can take place at Server  805 , at Repository  820 , or at an intermediary machine (not shown). During data access, the encoded log information is decoded by Box  835  using Decode Key  830  and delivered to Reporting system  840 , such as the Data Access Client  740  described in connection with  FIG. 7B . The data decoding process  835  can be performed at Repository  820 , at Reporting system  840 , or at an intermediary machine (not shown). The Key Manager  825  may be operated by the entity or entities generating the logs, by the entity or entities having access to the logs (if different), or by another entity, such as a third party or a government agency. The encoding and decoding illustrated in  FIG. 8A  may be employed on top of encryption mechanisms utilized to transmit the information securely between the Server  805  and Repository  820  and between Repository  820  and Reporting System  840 . 
     An alternative embodiment of encoding and decoding of logging information is illustrated in  FIG. 8B . Server  855 , Repository  870  and Reporting system  895  are operated in substantially the same way as Server  805 , Repository  820  and Reporting system  840  described above in connection with  FIG. 8A .  FIG. 8B  utilizes two key managers, Key Manager  850  and Key Manager  890  for generating pairs of encode and decode keys. Key Manager  850  generates encode key  864  and decode key  886  and Key Manager  890  generates encode key  866  and decode key  884 . Log information from Server  855  is encoded with both encode keys, first with encode key  864  at box  860  and then with encode key  866  at box  862 . The encoding processes  860  and  862  can take place at Server  855 , at Repository  820 , or at an intermediary machine (not shown). Additionally, encoding process  860  may take place in one location and encoding process  862  may take place at a different location. 
     During data access, the encoded log information is decoded first at box  880  using decode key  884 , then at box  882  using decode key  886  and then delivered to Reporting system  895 . The data decoding processes  880  and  882  can be performed at Repository  870 , at Reporting system  895 , or at an intermediary machine (not shown). Additionally decoding process  880  may take place at one location and decoding process  882  may take place at a different location. Key Managers  850  and  890  may be operated by the entity or entities generating the logs, by the entity or entities having access to the logs (if different), or by another entity, such as a third party or a government agency. Additionally, different entities may operate Key Manager  850  and  890 . For example, Key Manager  850  may be co-located with Server  855  and Key Manager  890  may be co-located with Reporting system  895 . In the case that encode key  866  and decode key  886  are considered “public” keys and encode key  864  and decode key  884  are considered “private” keys, then the embodiment of  FIG. 8B  accomplishes both authentication and encryption of log information stored in Repository  870 . The embodiment of  FIG. 8B  allows information to be protected even when multiple entities are involved in the generation, maintenance and utilization of the information. Those of skill in the art will appreciate that there are many alternative schemes for encrypting and authenticating the data that is stored the remote repository. 
     In one embodiment of the present invention, encode/decode key pairs  815 / 830 ,  864 / 886  and  866 / 884  are designed to be newly generated periodically. For example Key Manager  825 ,  850  and  890  could generate new key pairs every day and distribute them as appropriate. This would allow information to be easily made inaccessible by deleting the decryption keys. For example, by destroying decryption key  884  and all copies, the information associated with that day can be effectively deleted. The same key management policy can be employed to group other information, such as according to groups of users, kinds of activity, etc. The application of a decryption key destruction policy to enforce specific data access specifications can be used in addition to or instead of a repository access policy as was described above in connection with Data Access Client  740 . 
     The present invention has been described above in connection with several preferred embodiments. This has been done for purposes of illustration only, and variations of the inventions will be readily apparent to those skilled in the art and also fall within the scope of the invention.