Authentication (from Greek: αὐθεντικός authentikos, "real, genuine," from αὐθέντης authentes, "author") is the act of confirming the truth of an attribute of a single piece of data (a datum) claimed true by an 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 authenticity of a website with a digital certificate, determining the age of an artifact by carbon dating, or ensuring that a product is what its packaging and labeling claim to be.
other words, authentication often involves verifying the validity of at least one form of identification.
Authentication is relevant to multiple fields. In art, antiques and anthropology, a common problem is verifying that a given artifact was produced by a certain person or in a certain place or period of history. In computer science, verifying a person's identity is often required to allow 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. Centralized authority-based trust relationships back most secure internet communication through known public certificate authorities; decentralized peer-based trust, also known as a web of trust, is used for personal services such as email or files (pretty good privacy, GNU Privacy Guard) and trust is established by known individuals signing each other's cryptographic key at Key signing parties, for instance.
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. Anarchaeologist, on the other hand, might use carbon dating to verify the age of an artifact, do a chemical analysis of the materials used, or compare the style of construction or decoration to other artifacts of similar origin. The physics of sound and light, and comparison with a known physical environment, can be used to examine the authenticity of audio recordings, photographs, or videos. Documents can be verified as being created on ink or paper readily available at the time of the item's implied creation.
Attribute comparison may be vulnerable to forgery. In general, it relies on the facts that creating a forgery indistinguishable from a genuine artifact requires expert knowledge, that mistakes are easily made, and that the amount of effort required to do so is considerably greater than the amount of profit that can be gained from the forgery.
In art and antiques, certificates are of great importance for authenticating an object of interest and value. Certificates can, however, also be forged, and the authentication of these poses a problem. For instance, the son of Han van Meegeren, the well-known art-forger, forged the work of his father and provided a certificate for its provenance as well; see the article Jacques van Meegeren.
Criminal and civil penalties for fraud, forgery, and counterfeiting can reduce the incentive for falsification, depending on the risk of getting caught.
Currency and other financial instruments commonly use this second type of authentication method. Bills, coins, and cheques incorporate hard-to-duplicate physical features, such as fine printing or engraving, distinctive feel, watermarks, and holographic imagery, which are easy for trained receivers to verify.
The third type of authentication relies on documentation or other external affirmations. In criminal courts, the rules of evidence often require establishing the chain of custody of evidence presented. This can be accomplished through a written evidence log, or by testimony from the police detectives and forensics staff that handled it. Some antiques are accompanied by certificates attesting to their authenticity. Signed sports memorabilia is usually accompanied by a certificate of authenticity. These external records have their own problems of forgery and perjury, and are also vulnerable to being separated from the artifact and lost.
In computer science, a user can be given access to secure systems based on user credentials that imply authenticity. A network administrator can give a user a password, or provide the user with a key card or other access device to allow system access. In this case, authenticity is implied but not guaranteed.
Consumer goods such as pharmaceuticals, perfume, fashion clothing can use all three forms of authentication to prevent counterfeit goods from taking advantage of a popular brand's reputation (damaging the brand owner's sales and reputation). As mentioned above, having an item for sale in a reputable store implicitly attests to it being genuine, the first type of authentication. The second type of authentication might involve comparing the quality and craftsmanship of an item, such as an expensive handbag, to genuine articles. The third type of authentication could be the presence of a trademark on the item, which is a legally protected marking, or any other identifying feature which aids consumers in the identification of genuine brand-name goods. With software, companies have taken great steps to protect from counterfeiters, including adding holograms, security rings, security threads and color shifting ink.
The ways in which someone may be authenticated fall into three categories, based on what are known as the factors of authentication: something the user knows, something the user has, and something the user is. Each authentication factor covers a range of elements used to authenticate or verify a person's identity prior to being granted access, approving a transaction request, signing a document or other work product, granting authority to others, and establishing a chain of authority.
Security research has determined that for a positive authentication, elements from at least two, and preferably all three, factors should be verified. The three factors (classes) and some of elements of each factor are:
- the knowledge factors: Something the user knows (e.g., a password, Partial Password, pass phrase, or personal identification number (PIN), challenge response (the user must answer a question, or pattern), Security question
- the ownership factors: Something the user has (e.g., wrist band, ID card, security token, cell phone with built-inhardware token, software token, or cell phone holding a software token)
- the inherence factors: Something the user is or does (e.g., fingerprint, retinal pattern, DNA sequence (there are assorted definitions of what is sufficient), signature, face, voice, unique bio-electric signals, or other biometricidentifier).
Counterfeit products are often offered to consumers as being authentic. Counterfeit consumer goods such as electronics, music, apparel, and counterfeit medications have been sold as being legitimate. Efforts to control the supply chain and educate consumers help ensure that authentic products are sold and used. Even security printing on packages, labels, and nameplates, however, is subject to counterfeiting.
A secure key storage device can be used for authentication in consumer electronics, network authentication, license management, supply chain management, etc. Generally the device to be authenticated needs some sort of wireless or wired digital connection to either a host system or a network. Nonetheless, the component being authenticated need not be electronic in nature as an authentication chip can be mechanically attached and read through a connector to the host e.g. an authenticated ink tank for use with a printer. For products and services that these Secure Coprocessors can be applied to, they can offer a solution that can be much more difficult to counterfeit than most other options while at the same time being more easily verified.
Packaging and labeling can be engineered to help reduce the risks of counterfeit consumer goods or the theft and resale of products. Some package constructions are more difficult to copy and some have pilfer indicating seals. Counterfeit goods, unauthorized sales (diversion), material substitution and tampering can all be reduced with these anti-counterfeiting technologies. Packages may include authentication seals and usesecurity printing to help indicate that the package and contents are not counterfeit; these too are subject to counterfeiting. Packages also can include anti-theft devices, such as dye-packs, RFID tags, or electronic article surveillance tags that can be activated or detected by devices at exit points and require specialized tools to deactivate. Anti-counterfeiting technologies that can be used with packaging include:
- Taggant fingerprinting - uniquely coded microscopic materials that are verified from a database
- Encrypted micro-particles - unpredictably placed markings (numbers, layers and colors) not visible to the human eye
- Holograms - graphics printed on seals, patches, foils or labels and used at point of sale for visual verification
- Micro-printing - second line authentication often used on currencies
- Serialized barcodes
- UV printing - marks only visible under UV light
- Track and trace systems - use codes to link products to database tracking system
- Water indicators - become visible when contacted with water
- DNA tracking - genes embedded onto labels that can be traced
- Color shifting ink or film - visible marks that switch colors or texture when tilted
- Tamper evident seals and tapes - destructible or graphically verifiable at point of sale
- 2d barcodes - data codes that can be tracked
- RFID chips
The authentication of information can pose special problems with electronic communication, such as vulnerability to man-in-the-middle attacks, whereby a third party taps into the communication stream, and poses as each of the two other communicating parties, in order to intercept information from each. Extra identity factors can be required to authenticate each party's identity.
Literary forgery can involve imitating the style of a famous author. If an original manuscript, typewritten text, or recording is available, then the medium itself (or its packaging — anything from a box to e-mail headers) can help prove or disprove the authenticity of the document.
However, text, audio, and video can be copied into new media, possibly leaving only the informational content itself to use in authentication.
Various systems have been invented to allow authors to provide a means for readers to reliably authenticate that a given message originated from or was relayed by them. These involve authentication factors like:
- A difficult-to-reproduce physical artifact, such as a seal, signature, watermark, special stationery, or fingerprint.
- A shared secret, such as a passphrase, in the content of the message.
- An electronic signature; public-key infrastructure is often used to cryptographically guarantee that a message has been signed by the holder of a particular private key.
The opposite problem is detection of plagiarism, where information from a different author is passed off as a person's own work. A common technique for proving plagiarism is the discovery of another copy of the same or very similar text, which has different attribution. In some cases, excessively high quality or a style mismatch may raise suspicion of plagiarism.
Determining the truth or factual accuracy of information in a message is generally considered a separate problem from authentication. A wide range of techniques, from detective work, to fact checking in journalism, to scientific experiment might be employed.
Determining the truth or factual accuracy of information in a message is generally considered a separate problem from authentication. A wide range of techniques, from detective work, to fact checking in journalism, to scientific experiment might be employed.
It is sometimes necessary to authenticate the veracity of video recordings used as evidence in judicial proceedings. Proper chain-of-custody records and secure storage facilities can help ensure the admissibility of digital or analog recordings by the Court.In literacy, authentication is a readers’ process of questioning the veracity of an aspect of literature and then verifying those questions via research. The fundamental question for authentication of literature is - Do you believe it? Related to that, an authentication project is therefore a reading and writing activity which students documents the relevant research process . It builds students' critical literacy. The documentation materials for literature go beyond narrative texts and likely include informational texts, primary sources, and multimedia. The process typically involves both internet and hands-on library research. When authenticating historical fiction in particular, readers considers the extent that the major historical events, as well as the culture portrayed (e.g., the language, clothing, food, gender roles), are believable for the time period.
Historically, fingerprints have been used as the most authoritative method of authentication, but recent court cases in the US and elsewhere have raised fundamental doubts about fingerprint reliability.[citation needed] Outside of the legal system as well, fingerprints have been shown to be easilyspoofable, with British Telecom's top computer-security official noting that "few" fingerprint readers have not already been tricked by one spoof or another. Hybrid or two-tiered authentication methods offer a compelling solution, such as private keys encrypted by fingerprint inside of a USB device.
In a computer data context, cryptographic methods have been developed (see digital signature andchallenge-response authentication) which are currently not spoofable if and only if the originator's key has not been compromised. That the originator (or anyone other than an attacker) knows (or doesn't know) about a compromise is irrelevant. It is not known whether these cryptographically based authentication methods are provably secure, since unanticipated mathematical developments may make them vulnerable to attack in future. If that were to occur, it may call into question much of the authentication in the past. In particular, a digitally signed contract may be questioned when a new attack on the cryptography underlying the signature is discovered.