초록 ▼

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 sign

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.

대표청구항 ▼

In a communication system having a plurality of terminal devices coupled to a channel over which users may exchange messages, at least some of said user\s having a public key and an associated private key, a method for controlling authority in a hierarchical manner among a group of users, comprising

In a communication system having a plurality of terminal devices coupled to a channel over which users may exchange messages, at least some of said user\s having a public key and an associated private key, a method for controlling authority in a hierarchical manner among a group of users, comprising the steps of: specifying at least first and second digital authority defining data structures, said data structures having digital values which can be associated with at least one user\s private key, said step of specifying including the step of digitally specifying a set of authorities from a sufficient plurality of authorities so that a first user may digitally delegate authorities to second and third users so that the authorities delegated to the second user are different than those delegated to the third user, providing that the first user\s digital authority defining data structure allows for such delegation; and digitally signing by the first user the second digital data structure so that signatures performed by the second user\s private key associated with the second data structure will be recognized upon an electronic analysis of the digital signature as having been granted said authority by the first user in accordance with the first user\s authority-defining data structure.