Method for providing authentication assurance in a key-binding system

Abstract

A name-to-target binding system generates certificates for use in authenticating a target key. In the system the certificate includes a first key. At least one attribute is assigned to the first key. A liability value is assigned to the combination of the first key and the at least one attribute. The system includes a second key used to sign a combination of the first key, the at least one attribute and the liability value wherein the second key is associated with the insurer agreeing to be liable for the liability value.

What is claimed is:  
     
         1 . A method for assessing a level of assurance of reaching a target from a source along a chain of authority of certificates comprising: 
 determining a minimum insurance amount in a chain of authority of certificates, each of the certificates including a key owned by one entity, an attribute associated with the key of the one entity, an insurance amount associated with the key of the one entity, and that key's associated attribute being signed by a key of an entity giving authentication assurance; and    said determining the minimum insurance amount in the chain of authority of certificates being performed by 
 receiving an insurance amount for each certificate in the chain of authority of certificates,  
 determining the minimum insurance amount from among the received insurance amounts, and  
 outputting the minimum insurance amount.  
   
     
     
         2 . The method of  claim 1  wherein in each of said certificates said attribute includes an identity of said one entity.  
     
     
         3 . The method of  claim 1  wherein said insurance amount represents an amount for which the entity giving authentication assurance is liable with regard to the accuracy of the certificate.  
     
     
         4 . A method for assessing a level of assurance for reaching a target from a source, the source and target being connected by a plurality of chains of authority, each node along each chain of authority including a value for an insurance metric, the method comprising: 
 determining a minimum value from among the values for the insurance metric for each chain of authority from the plurality of the chains of authority; and    calculating a level of assurance for reaching the target from the source based on the determined minimum value.    
     
     
         5 . The method of  claim 4  wherein the insurance metric is an insurance dollar amount for certificates.  
     
     
         6 . The method of  claim 4  wherein the level of assurance is the determined minimum value.  
     
     
         7 . The method of  claim 4  wherein the determination of a minimum value from among the values of the insurance metric for a chain of authority is made based on the values of the insurance metric for each node within the chain of authority.