05606609 is referenced by 604 patents and cites 64 patents.

The integrity or the signator of an electronic document can be verified by embedding a security object, for example, supported by an object linking and embedding (OLE) capability, in the electronic document at a location selected by the signator. The embedded security object includes security information and an identifier for invoking the processing of the security information. The security information may include a document digest that characterizes the electronic document at the time the security object was embedded, a signature digest that identifies the signator and that characterizes the instance of the embedded security object, and the signator's electronic chop, which may be the signator's digitized signature or other graphic image. In addition, the security information can be encrypted using either private key encryption or public key encryption. When the electronic document is later displayed, the identifier invokes processing that decrypts the security information and calculates the document digest based on the current state of the electronic document. The signator of the electronic document can be verified based upon the result of the decryption. The integrity of the electronic document can be verified if the decrypted document digest matches the calculated document digest. If the signator and the document integrity are confirmed, the electronic chop is displayed in the document. If, however, the signator or document integrity are not verified, the electronic chop is not displayed. In addition, a warning message may be displayed if verification fails.

Electronic document verification system and method
Application Number
Publication Number
Application Date
September 19, 1994
Publication Date
February 25, 1997
James M Adler
Ocean Beach
Peter B Houser
Banner & Witcoff
Scientific Atlanta
H04L 9/00
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