  authentication (from  authentikos, "real, genuine," from Î±á½Î¸Î­Î½ÏÎ·Ï authentes, "author") is the act of confirming the truth of an attribute of a single piece of data (datum) or entity. in contrast with identification which refers to the act of stating or otherwise indicating a claim purportedly attesting to a person or thing's identity, authentication is the process of actually confirming that identity. it might involve confirming the identity of a person by validating their identity documents, verifying the validity of a website with a digital certificate, tracing the age of an artifact by carbon dating, or ensuring that a product is what its packaging and labeling claim to be. in other words, authentication often involves verifying the validity of at least one form of identification. ==methods==  authentication has relevance to multiple fields. in art, antiques, and anthropology, a common problem is verifying that a given artifact was produced by a certain person or was produced in a certain place or period of history. in computer science, verifying a person's identity is often required to secure access to confidential data or systems. authentication can be considered to be of three types: the first type of authentication is accepting proof of identity given by a credible person who has first-hand evidence that the identity is genuine. when authentication is required of art or physical objects, this proof could be a friend, family member or colleague attesting to the item's provenance, perhaps by having witnessed the item in its creator's possession. with autographed sports memorabilia, this could involve someone attesting that they witnessed the object being signed. a vendor selling branded items implies authenticity, while he or she may not have evidence that every step in the supply chain was authenticated. this hear-say authentication has no use case example in the context of computer security. the second type of authentication is comparing the attributes of the object itself to what is known about objects of that origin. for example, an art expert might look for similarities in the style of painting, check the location and form of a signature, or compare the object to an old photograph. an archaeologist might use carbon dating to verify the age of an artifact, do a chemical analysis of the materials used, or compare the style of co
Access_control Applications_of_cryptography Authentication_methods Computer_access_control Notary Packaging