Patent ID: 6826686
Filing Date: 2004-11-30
Classification: G06F,H04L

Abstract:
A method for securely changing an existing password associated with a user identifier (userid) on a host computer to a new password, wherein said passwords enable a user associated with said userid at a local computer to access information on said host computer across a network; said method comprising the steps of:sending, by the local computer, the userid and a first nonce to the host computer; replying, by the host computer to the local computer, with a second nonce; generating, by the local computer, a first digest of the userid and the existing password and a second digest of the userid and the new password; creating, by the local computer, an authentication token and an authentication token mask wherein said authentication token is a hash function of the first digest, first nonce and second nonce, and said token mask is a hash function of the second digest, first nonce plus a predetermined value and the second nonce; generating, by the local computer, a protected digest by exclusive-oring the second digest with the token mask; sending, by the local computer to the host computer, the userid, authentication token and the protected digest; verifying, by the host computer, the validity of the authentication token; and, accepting the new password to replace the existing password if the authentication token is valid.