Authentication method

A method for authenticating the identity of a requester of access to a secured resource, said method for authenticating comprising the steps of:

• receiving from a service client a request for access to a secured resource, said request for access having been submitted to said service client by a requester purporting to be an authorized user of said secured resource;
• selecting a plurality of randomly selected symbols;
• generating a challenge string with a computer server contemporaneously with selecting said plurality of randomly selected symbols, said challenge string being a random string comprising said plurality of randomly selected symbols and at least one null character, said null character being a specially designated symbol intended to indicate the absence from said challenge string of a single symbol, wherein said generating step and said selecting step are
• communicating said challenge string through a discrete channel to said authorized user that said requester purports to be;
• receiving from said service client a response string formulated by using symbols of a private string to replace the at least one null character of said challenge string, the private string being only known to said authorized user and said computer server;
• evaluating said response string to authenticate the identity of said requester;
• and
• wherein:
• said secured resource comprises a common identifier by which said secured resource may be generally identified outside of an authentication system;
• and
• said request for access comprises insufficient content for said service client to determine said common identifier.