05005200 is referenced by 342 patents and cites 13 patents.

A public key cryptographic system is disclosed with enhanced digital signature certification which authenticates the identity of the public key holder. A hierarchy of nested certifications and signatures are employed which indicate the authority and responsibility levels of the individual whose signature is being certified. The certifier in constructing a certificate generates a special message that includes fields identifying the public key which is being certified, and the name of the certifiee. The certificate is constructed by the certifier to define the authority which is being granted and which may relate to a wide range of authorizations, delegation responsibilities or restrictions given to, or placed on the certifiee. Methodology is also disclosed by which multiple objects such as, for example, a cover letter, an associated enclosed letter, an associated graphics file, etc., are signed together. Methodology is also disclosed for digitally signing documents in which a digital signature is generated for both computer verification and for reverification if a document needs to be reconfirmed by reentering from a paper rendition.

Title
Public key/signature cryptosystem with enhanced digital signature certification
Application Number
155467
Publication Number
5005200
Application Date
March 7, 1989
Publication Date
April 2, 1991
Inventor
Addison M Fischer
60 14th Ave. S., Naples, 33942
FL, US
Agent
Nixon & Vanderhye
IPC
H04K 1/00
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