1. Statement of the Technical Field
The present invention relates to the field of data communications security and encryption and more particularly to signing and validating network distributable content.
2. Description of the Related Art
Malicious computer users, commonly referred to as “hackers”, have grown bolder each day, adding to their growing repertory of hacking exploits while leveraging new combinations of old exploits to create new threats of ever increasing sophistication. Each new threat generally attempts to perpetrate an on-line fraud of which the computing public is to remain unaware. One type of on-line scam which has become prevalent involves the creation and wide-scale distribution of an electronic message (e-mail) that appears to the casual user to have originated from a trusted party.
Typically, the message within the email can demand that the recipient select a hyperlink within the e-mail, or can cajole the recipient into selecting the hyperlink. Unbeknownst to the recipient, the hyperlink can lead to a content distribution site such as a Web site designed to obtain personal and confidential information. As an alternative, the message can ask the recipient to “re-enter” personal information such as a user identifier, password, credit card number or account number. As yet another alternative, the e-mail message can threaten to terminate the e-mail account of the recipient, assign the recipient a bad credit rating, or charge the credit card of the recipient unless the recipient provides certain personally identifying information.
As it will be apparent to the skilled artisan, the foregoing e-mail scam represents a confidence game having the sole purpose of persuading recipients to voluntarily provide personal information which later can be used for various fraudulent purposes. As noted, the hyperlink in the e-mail message typically directs the e-mail message recipient to a hacker-operated content distribution site which impersonates a content distribution site of a trusted party known and expected by the recipient. Non-email schemes for directing a victim to a hacker-operated content distribution site also are known and include Web advertising, search engine stuffing, “bogus” news or discussion group postings, or even an innocuous-appearing security site created by the hacker helpfully purporting to direct the user to an official bug-fix site.
Central to the hacker scam is the ability of the hacker to convincingly impersonate the trusted content distribution site. The degree of realism depends upon the specific techniques used by the hacker, as well as the gullibility of the user. The effectiveness of the sham also can vary with the version, patch level, and configuration settings of a content browser. Several variations exist in respect to this scam. For instance, in one variation, a complete copy of a Web site can be created and hosted at a different Web site controlled by the hacker. The link to the spoof Web site can be constructed to appear as if the link refers to the legitimate site, though critical portions of the link will cause the misdirection of the link to the hacker controlled site. In another variation, the spoof content distribution site can be hosted at a domain which is but a misspelled derivative of the actual content distribution site.
U.S. patent application Publication No. 2002/0124172 to Manahan for METHOD AND APPARATUS FOR SIGNING AND VALIDATING WEB PAGES (hereinafter, “Manahan”) addresses the general problem of spoofing a Web site. In the Manahan publication, a Web page can be digitally signed using a private key to provide a digital signature. The Web page, digital signature and a digital certificate can be transmitted to the Web content browser of an end user which can use the digital certificate and digital signature to verify the content of the Web page. Nevertheless, the technology of the Manahan publication cannot account for the spoofing of the Web site itself from which the content originates.
Notably, the technology disclosed in the Manahan publication protects the integrity of the content, but does nothing to assure that the content is delivered from a known server. That is, in the Manahan publication, if signed content simply is copied intact and re-hosted on a different server controlled by a hacker, that server will distribute the original content and signature, which the user's browser will verify as being correct. In this situation the user's browser will not detect the danger that any personal information entered in response to the spoofed content is placed into the hands of an untrusted party, rather than the content owner who signed the content. In other words, where a victim inadvertently visits a spoofed Web site, the Manahan arrangement will be ineffective to protect the victim from the scam.