A method for verifying the source of an article of manufacture. A label having
information relating to the article is prepared and digitally signed or otherwise
encrypted to authenticate the information. The label and a tangible representation
of the digital signature or other encrypted information are then securely associated
with the article. The information relating to the article can include verifying
information such as an expiration date, unique identification of the article, identification
of an authorized provider of the article or a description of the article to protect
against unauthorized use of duplicate labels. The label can also include an unreproduceable
pattern such as a pattern of magnetic fibers embedded in the label and a digitally
signed description of the pattern.
