Abstract:
A method for providing textual information in a network environment, the method comprising: receiving a request via a network for text-editable textual information; converting the text-editable textual information into a non-text-editable textual format on line upon receiving the request; and sending the non-text-editable textual information via the network. Network-based systems are also disclosed.

Description:
FIELD OF THE INVENTION 
     The present invention relates to network security in general and particularly to methods and apparatus for preventing unauthorized reuse of text, images, and software transmitted via networks. 
     BACKGROUND OF THE INVENTION 
     Sending text, images, and software via communications networks, particularly computer networks, is known. In one well known network protocol, the Hypertext Transport Protocol or HTTP, best known as a transport protocol for the Internet-based World Wide Web or WWW, a computer terminal or “client” corrected to a network, such as the Internet, typically sends a request using software known as a “browser” to a server also connected to the network. Such requests may be for “Web pages,” documents constructed using Hypertext Markup Language or HTML and stored at the server, which are then rendered by the client browser into text and/or images. Other requests may be for software applications such as “applets” which are executed by an application engine at the client. Upon receiving a request, the server sends that which was requested to the client. 
     Preventing unauthorized reuse of text, images, and software provided via networks is difficult given the current state of the art. Text is usually provided in text-editable format which may be copied and reused at the client. While text may be converted to a graphic image at the server and thus provided in a non-text-editable format to the client, this is not practicable both due to the increased storage requires to store text as graphic images on the server, as well as the dynamic nature of requests such as search queries where the text results are not known until the query is executed and, therefore, the text cannot be converted to a graphic ahead of time. Images may be captured at the client from the client&#39;s video buffer and reused. Software applications including applets may be decompiled and reused a later date where a time-limited or access-limited use was originally intended. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide improved methods and apparatus for preventing unauthorized reuse of text, images, and software transmitted via networks. Text documents, and particularly HTML documents, from which text can be copied are rendered into non-text-editable graphical images at the server upon receiving a request from a client. Graphic images are rendered into a number of sub-images at the server upon receiving a request from a client. The sub-images are then sent to the requesting client together with an applet for displaying the sub-images in a manner that is visually perceived to substantially resemble the graphical image but which cannot be copied simply by taking a snapshot of the client&#39;s video buffer. Software applications including applets are provided with an embedded password that may be authenticated by a server to allow access to information for a limited time or under limited conditions. The password is invalidated at a predetermined time of based upon certain conditions, thus preventing future reuse and access to server information. 
     There is thus provided in accordance with a preferred embodiment of the present invention a method for providing textual information in a network environment, the method including receiving a request via a network for text-editable textual information, converting the text-editable textual information into a non-text-editable textual format on line upon receiving the request, and sending the non-text-editable textual information via the network. 
     Further in accordance with a preferred embodiment of the present invention the converting step includes converting the text-editable textual information into a non-text-editable graphical representation of the text-editable textual information. 
     Still further in accordance with a preferred embodiment of the present invention the converting step includes converting the text-editable textual information into the non-text-editable graphical representation the graphical representation includes at least one hyperlink. 
     Additionally in accordance with a preferred embodiment of the present invention the method further includes displaying the non-text-editable textual information via a computer terminal display. 
     Moreover in accordance with a preferred embodiment of the present invention the receiving step includes receiving the request from a computer terminal connected to the network at a server connected to the network, the converting step is performed at the server, and the sending step includes the server sending the non-text-editable textual information to the computer terminal via the network. 
     There is also provided in accordance with a preferred embodiment of the present invention a method for providing graphical information in a network environment, the method including receiving a request via a network for a graphical image, rendering the graphical image into a plurality of sub-images on line upon receiving the request, the sub-images are displayable in a manner that is visually perceived to substantially resemble the graphical image, and displaying the plurality of sub-images in the manner on a display via a video buffer the video buffer includes no more than one of the sub-images in its entirety at any given time. 
     Further in accordance with a preferred embodiment of the present invention the rendering step includes rendering the graphical image into a plurality of color separations of the graphical image. 
     Still further in accordance with a preferred embodiment of the present invention the rendering step includes rendering the graphical image into a plurality of sub-images the any of the plurality of sub-images includes an interference pattern. 
     Additionally in accordance with a preferred embodiment of the present invention the method further includes sending the plurality of sub-images via the network. 
     Moreover in accordance with a preferred embodiment of the present invention the displaying step includes displaying the plurality of sub-images via a computer terminal display. 
     Further in accordance with a preferred embodiment of the present invention the receiving step includes receiving the request from a computer terminal connected to the network at a server connected to the network, the rendering step is performed at the server, the method further includes sending the plurality of sub-images to the computer terminal via the network, and the displaying step includes displaying the plurality of sub-images via a computer terminal display. 
     There is also provided in accordance with a preferred embodiment of the present invention a method for limiting the operational life of software in a network environment, the method including providing a software application with an associated password to a client via a network, receiving a request for information from the software application via the network, the request including the associated password, authenticating the password, providing the information to the software application via the network while the associated password is valid, and invalidating the password coincident with an invalidation event. 
     Further in accordance with a preferred embodiment of the present invention the invalidating step includes invalidating the password at a predetermined time. 
     Still further in accordance with a preferred embodiment of the present invention the invalidating step includes invalidating the password after a predetermined elapsed time from when the request was received. 
     Additionally in accordance with a preferred embodiment of the present invention the invalidating step includes invalidating the password upon the detection of a loss of communication with the client. 
     Moreover in accordance with a preferred embodiment of the present invention the providing step includes providing the software application in the form of an applet. 
     Further in accordance with a preferred embodiment of the present invention the providing step includes providing the password assembled with the software application. 
     Still further in accordance with a preferred embodiment of the present invention the providing step includes generating the password at a server upon receiving the request at the server. 
     There is also provided in accordance with a preferred embodiment of the present invention a network-based textual information system including a computer terminal operative to send a request via a network for text-editable textual information, and a server operative to receive the request, convert the text-editable textual information into a non-text-editable textual format on line upon receiving the request, and send the non-text-editable textual information to the computer terminal via the network. 
     Further in accordance with a preferred embodiment of the present invention the non-text-editable textual format includes a non-text-editable graphical representation of the text-editable textual information. 
     Still further in accordance with a preferred embodiment of the present invention the non-text-editable graphical representation includes at least one hyperlink. 
     Additionally in accordance with a preferred embodiment of the present invention the server further includes a first storage area that is inaccessible to the computer terminal for storing the text-editable textual information and a second storage area that is accessible to the computer terminal for storing the non-text-editable textual information. 
     There is also provided in accordance with a preferred embodiment of the present invention a network-based graphical information system including a computer terminal operative to send a request via a network for a graphical image, and a server operative to receive the request, render the graphical image into a plurality of sub-images on line upon receiving the request, the sub-images are displayable in a manner that is visually perceived to substantially resemble the graphical image, and send the sub-images to the computer terminal via the network. 
     Further in accordance with a preferred embodiment of the present invention the computer terminal is operative to display the plurality of sub-images in the manner on a display via a video buffer the video buffer includes no more than one of the sub-images in its entirety at any given time. 
     Still further in accordance with a preferred embodiment of the present invention the plurality of sub-images includes a plurality of color separations of the graphical image. 
     Additionally in accordance with a preferred embodiment of the present invention any of the plurality of sub-images includes an interference pattern. 
     There is also provided in accordance with a preferred embodiment of the present invention a network-based software authentication system including a server including a password generator, password validation apparatus, a restricted-access storage area, a software application, and invalidation apparatus, the server is operative to a) cause the password generator to generate a password, b) provide the software application with the password to a client via a network, c) receive a request for information from the software application via the network, the request including the associated password, d) authenticate the password using the password validation apparatus, e) provide the information to the software application via the network while the associated password is valid, and f) invalidate the password using the invalidation apparatus coincident with an invalidation event. 
     Further in accordance with a preferred embodiment of the present invention the invalidation event includes the arrival of a predetermined time. 
     Still further in accordance with a preferred embodiment of the present invention the invalidation event includes the elapsing of a predetermined elapsed time from when the request was received. 
     Additionally in accordance with a preferred embodiment of the present invention the invalidation event includes the detection of a loss of communication with the client. 
     Moreover in accordance with a preferred embodiment of the present invention the software application includes an applet. 
     Further in accordance with a preferred embodiment of the present invention the password is assembled with the software application. 
     Still further in accordance with a preferred embodiment of the present invention the password is generated at the server upon receiving the request at the server. 
     It is noted that throughout the specification and claims the term “user” as it is used with respect to the use of a computer may refer to a human or surrogate therefor in combination with the computer terminal with which the human or surrogate interacts. Thus, unless otherwise specified, a reference to a user may connote a reference to the user&#39;s computer terminal, and a reference to a user&#39;s computer terminal may connote a reference to the user. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
     FIG. 1 is a simplified pictorial illustration of a system for preventing unauthorized reuse of text, the system constructed and operative in accordance with a preferred embodiment of the present invention; 
     FIG. 2 is a simplified block diagram of server  14  of FIG. 1; 
     FIG. 3 is a simplified pictorial illustration of a system for preventing unauthorized reuse of graphical images, the system constructed and operative in accordance with a preferred embodiment of the present invention; 
     FIG. 4 is a simplified block diagram of server  34  of FIG. 3; 
     FIGS. 5A and 5B and  5 C, taken together, are simplified pictorial flow illustrations of a method of displaying the sub-images of FIG. 3; 
     FIG. 6 is a simplified pictorial illustration of a system for preventing unauthorized reuse of software applications, the system constructed and operative in accordance with a preferred embodiment of the present invention; and 
     FIG. 7 is a simplified block diagram of server  64  of FIG.  6 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference is now made to FIG. 1 which is a simplified pictorial illustration of a system  10  for preventing unauthorized reuse of text, the system constructed and operative in accordance with a preferred embodiment of the present invention. System  10  preferably includes a communications network  12 , such as the Internet, with a server  14  connected to communications network  12 . A client  16  is also shown connected to communications network  12  and typically comprises any known computer terminal configured for communication via network  12  as is well known. Server  14  typically includes a storage area  18  that is accessible to clients and a storage area  20  that is not accessible to clients. 
     Typical operation of system  10  begins with client  16  sending a request for textual information, such as a document  22 , to server  14  via network  12 . The request may be made using known means, such as by selecting a hyperlink to a World Wide Web page using a browser. By “textual information” it is meant information that is to be presented as text, such as a news article or the results of a search. It is a particular feature of the invention that server  14  stores textual information in a text-editable format, such as in HTML or other known format, in storage area  20  that may not be directly accessed by clients. By “text-editable” it is meant that the textual information in its present form could be copied as text and reused, such as by pasting the copied text into a word processor and deleting words, etc. 
     Upon receiving the request from client  16 , server  14  determines whether the textual information sought is in area  18  that is accessible to client  16 , or in area  20  that is not accessible to client  16 . If the textual information is in area  20 , server  14  renders the textual information on line into a non-text-editable format, such as a document  24 , using methods known in the art. By “non-text-editable” it is meant that the textual information in its present form could not be copied as text and reused, such as by pasting the copied text into a word processor and deleting words, etc. For example, search results may be converted from a text-editable format to a non-text-editable format by rendering the text into a graphical format, such as GIF or JPEG, or by performing text-to-speech synthesis. 
     Upon rendering the textual information into a non-text-editable format, server  14  may then send the non-text-editable textual information over network  12  to client  16  where it may be output to a device such as a computer display or printer. Alternatively, server  14  may store the non-text-editable information in area  18  that is accessible to client  16 . Server  12  may then generate an HTML document including a hyperlink to the rendered text and send it to client  16 . Client  16  then selects the hyperlink and retrieves the rendered text from area  18 . In this manner, text in HTML format that itself includes hyperlinks may be rendered into a graphical client map that preserves both the textual presentation as well as the hyperlinks. 
     Additional reference is now made to FIG. 2 in which server  14  is shown as typically including a filter  26  which determines whether or not requests are for textual information and whether the textual information requested is stored in area  18  or area  20 . Server  14  also includes a rendering engine  28  capable of rendering HTML or other text elements to graphical format as is well known in the art. One such rendering engine is NGLAYOUT, commercially available from Netscape Communications Corporation. 
     Reference is now made to FIG. 3 which is a simplified pictorial illustration of a system  30  for preventing unauthorized reuse of graphical images, the system constructed and operative in accordance with a preferred embodiment of the present invention. System  30  preferably includes a communications network  32 , a server  34  connected to communications network  32 , and client  36 , similar respectively to network  12 , server  14 , and client  16  as described with reference to FIG. 1 except as otherwise described herein. Server  34  typically includes a storage area  38  that is accessible to clients and a storage area  40  that is not accessible to clients. 
     Typical operation of system  30  begins with client  36  sending a request for a graphical image, such as an image  42 , to server  34  via network  32 . The request may be made using known means, such as by selecting a hyperlink to a World Wide Web page using a browser. It is a particular feature of the invention that information that server  34  store graphical images in storage area  40  that may not be directly accessed by clients. 
     Upon receiving the request from client  36 , server  34  determines whether the graphical image sought is in area  38  that is accessible to client  36 , or in area  40  that is not accessible to client  36 . If the graphical image is in area  40 , server  34  decomposes the graphical image on line into a number of sub-images using methods known in the art. For example, a color image of a horse may be decomposed into a number of color-separated sub-images, such as sub-images  42 A- 42 C being separated into red, green, and blue components respectively, using known color separation techniques. Alternatively or additionally, interference patterns may be randomly introduced into multiple copies of an image. Any known image decomposition method may be used provided that no sub-image, when viewed independently, may be visually perceived to substantially resemble the graphical image from which it was derived. 
     Upon decomposing the graphical image into sub-images, server  34  may then send the sub-images  42 A- 42 C over network  32  to client  36  where it may be output such as via a computer display in a manner that is visually perceived to substantially resemble the original graphical image  42 , such as is known in the art using techniques such as animated GIF. Alternatively, server  34  may store the sub-images in area  38  that is accessible to client  36 . Server  32  may then generate an HTML document including a hyperlink to the rendered sub-images and send it to client  36 . Client  36  then selects the hyperlink and retrieves the sub-images from area  18 . Server  34  may also provide an applet  44  to client  36  for controlling the display of the sub-images at client  36 . 
     Additional reference is now made to FIG. 4 in which server  34  is shown as typically including a filter  46  which determines whether or not requests are for graphical images and whether the graphical image requested is stored in area  38  or area  40 . Server  34  also includes a decomposition engine  48  capable of performing color separations or introducing interference patterns into multiple copies of an image as is known in the art. 
     Additional reference is now made to FIGS. 5A and 5B which, taken together, are simplified pictorial flow illustrations of sub-images  42 A- 42 C being displayed on client  36 . Sub-images  42 A,  42 B, and  42 C are shown being displayed on a computer display  52  of client  36  in succession over a time period t starting at time index t 0  and concluding at a time index t 1  of a time line  50 . A video buffer  54  associated with display  52  contains the sub-image being currently displayed. It is a particular feature of the invention that at no time does video buffer  54  contain more than one entire sub-image. FIG. 5B shows the result of displaying sub-images  42 A- 42 C in succession over time period t, with the sub-images being visually perceived as a composite image  42 ′ which substantially resembles graphical image  42 , as is well known in the art of visual perception. 
     FIG. 5C is functionally equivalent to FIG. 5A with the exception that sub-images  42 A- 42 C of FIG. 5A are replaced with sub-images  42 D,  42 E, and  42 F representing multiple copies of image  42  (FIG. 3) into which interference patterns  56  have been introduced. When displayed in the manner described in FIG. 5B it is believed that composite image  42 ′ may be visually perceived to substantially resemble graphical image  42  where the interference patterns  56  are visually discounted. 
     Reference is now made to FIG. 6 which is a simplified pictorial illustration of a system  60  for preventing unauthorized reuse of software, the system constructed and operative in accordance with a preferred embodiment of the present invention. System  60  preferably includes a communications network  62 , a server  64  connected to communications network  62 , and client  66 , similar respectively to network  12 , server  14 , and client  16  as described with reference to FIG. 1 except as otherwise described herein. Server  64  typically includes a restricted-access storage area  68 , a software application such as an applet  70 , and apparatus for validating passwords, such as a table  72  of valid passwords. 
     Typical operation of system  60  begins with client  66  sending a request for applet  70  to server  64  via network  62 . The request may be made using known means, such as by selecting a hyperlink to a World Wide Web page using a browser. Upon receiving the request from client  66 , server  64  preferably generates a unique password which it stores in table  72 . Server  64  then sends the applet along with the password client  66 . The password may be embedded into the applet, such as in a predetermined location within the applet code. 
     Client  66  may use the applet to send requests to server  64  for information stored in restricted access storage  68 . The requests are preferably accompanied by the password. Upon receiving the request, server  64  authenticates the password by looking it up in table  72 . If the password is valid, server  64  provides the information requested from restricted access storage  68  to client  66 . 
     It is a particular feature of the present invention for server  64  to invalidate a password in table  72 , such as by removing it from table  72 , upon the occurrence of an invalidation event. Such an invalidation event may include the arrival of a predetermined time, the passage of a predetermined amount of time from when a request was last received, and the detection of a loss of communication with the client. 
     Additional reference is now made to FIG. 7 in which server  64  is shown as typically including a password generator  74  for generating passwords and, optionally, inserting a password, such as a password  76 , into the code of applet  70 . Server  64  also preferably comprises invalidation apparatus  78  for invalidating passwords as described above. 
     It is appreciated that components of the present invention may be implemented in computer hardware, software, or any suitable combination thereof using conventional techniques. 
     It is appreciated that various features of the invention which are, for clarity, described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment may also be provided separately or in any suitable combination. 
     It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention is defined only by the claims that follow: