A signature (; from la, signare, "to sign") is a handwritten (and often stylized) depiction of someone's name, nickname, or even a simple "X" or other mark that a person writes on documents as a proof of identity and intent. The writer of a signature is a signatory or signer. Similar to a handwritten signature, a signature work describes the work as readily identifying its creator. A signature may be confused with an autograph, which is chiefly an artistic signature. This can lead to confusion when people have both an autograph and signature and as such some people in the public eye keep their signatures private whilst fully publishing their autograph.

Function and types

The traditional function of a signature is to permanently affix to a document a person's uniquely personal, undeniable self-identification as physical evidence of that person's personal witness and certification of the content of all, or a specified part, of the document. For example, the role of a signature in many consumer contracts is not solely to provide evidence of the identity of the contracting party, but also to provide evidence of deliberation and informed consent. In many countries, signatures may be witnessed and recorded in the presence of a notary public to carry additional legal force. In some jurisdictions, an illiterate signatory can make a "mark" (often an "X" but occasionally a personalized symbol) on legal documents, so long as the document is countersigned by a literate witness. In some countries, illiterate people place a thumbprint on legal documents in lieu of a written signature. In the United States, signatures encompass marks and actions of all sorts that are indicative of identity and intent. The legal rule is that unless a statute specifically prescribes a particular method of making a signature it may be made in any number of ways. These include by a mechanical or rubber stamp facsimile. A signature may be made by the purported signatory; alternatively someone else duly authorized by the signatory, acting in the signer's presence and at the signatory's direction, may make the signature. Many individuals have much more fanciful signatures than their normal
cursive Cursive (also known as script, among other names) is any style of penmanship in which characters are written joined in a flowing manner, generally for the purpose of making writing faster, in contrast to block letters. It varies in functionali ...
writing, including elaborate ascenders,
descender In typography and handwriting, a descender is the portion of a letter that extends below the baseline of a font. For example, in the letter ''y'', the descender is the "tail", or that portion of the diagonal line which lies below the ''v'' ...
s and exotic flourishes, much as one would find in calligraphic writing. As an example, the final "k" in
John Hancock John Hancock ( – October 8, 1793) was an American Founding Father, merchant, statesman, and prominent Patriot of the American Revolution. He served as president of the Second Continental Congress and was the first and third Governor ...
's famous signature on the US Declaration of Independence loops back to underline his name. This kind of flourish is also known as a '' paraph'', a French term meaning flourish, initial or signature. The paraph is used in graphology analyses. Several cultures whose languages use writing systems other than alphabets do not share the Western notion of signatures per se: the "signing" of one's name results in a written product no different from the result of "writing" one's name in the standard way. For these languages, to write or to sign involves the same written characters. Also see
Calligraphy Calligraphy (from el, link=y, καλλιγραφία) is a visual art related to writing. It is the design and execution of lettering with a pen, ink brush, or other writing instrument. Contemporary calligraphic practice can be defined ...

Mechanically produced signatures

Special signature machines, called
autopen An autopen (or signing machine) is a device used for the automatic signing of a signature. Prominent individuals may be asked to provide their signatures many times a day, such as celebrities receiving requests for autographs, or politicians sig ...
s, are capable of automatically reproducing an individual's signature. These are typically used by people required to sign a lot of printed matter, such as celebrities, heads of state or CEOs. More recently, Members of Congress in the United States have begun having their signature made into a TrueType font file. This allows staff members in the Congressman's office to easily reproduce it on correspondence, legislation, and official documents. In the East Asian languages of Chinese, Japanese, and Korean, people traditionally use stamp-like objects known as ''name- seals'' with the name carved in ''tensho'' script (''
seal script Seal script, also sigillary script () is an ancient style of writing Chinese characters that was common throughout the latter half of the 1st millennium BC. It evolved organically out of the Zhou dynasty bronze script. The Qin variant of sea ...
'') in lieu of a handwritten signature.

Wet signatures

A wet signature is a person's name written in their own hand with ink. Some government agencies require that professional persons or official reviewers sign originals and all copies of originals to authenticate that they personally viewed the content. In the United States this is prevalent with architectural and construction plans. Its intent is to prevent mistakes or fraud but the practice is not known to be effective.

Detection of forged signatures

Handwriting experts say "it is extremely difficult for anyone to be able to figure out if a signature or other very limited writing sample has been forged." High volume review of signatures, to decide if a signature is true or forged, occurs when election offices decide whether to accept absentee ballots arriving from voters, and possibly when banks decide whether to pay checks. The highest error rates in signature verification are found with lay people, higher than for computers, which in turn make more errors than experts. There have been concerns that signature reviews improperly reject ballots from young and minority voters at higher rates than others, with no or limited ability of voters to appeal the rejection. When errors are made with bank checks, the payer can ask the bank for corrections. A fifth of adults in the United Kingdom say they sign so rarely they have no consistent signature, including 21% of people 18-24 and 16% of people over age 55. 55% of UK adults rarely sign anything. Researchers have published error rates for computerized signature verification. They compare different systems on a common database of true and false signatures. The best system falsely rejects 10% of true signatures, while it accepts 10% of forgeries. Another system has error rates on both of 14%, and the third-best has error rates of 17%.These systems handle scanned ("offline") signatures from multiple people ("WI, writer-independent"). It is possible to be less stringent and reject fewer true signatures, at the cost of also rejecting fewer forgeries. Computer algorithms:
look for a certain number of points of similarity between the compared signatures ... a wide range of algorithms and standards, each particular to that machine's manufacturer, are used to verify signatures. In addition, counties have discretion in managing the settings and implementing manufacturers' guidelines ... there are no statewide standards for automatic signature verification ... most counties do not have a publicly available, written explanation of the signature verification criteria and processes they use.
In an experiment, experts rejected 5% of true signatures and 71% of forgeries. They were doubtful about another 57% of true signatures and 27% of forgeries. If computer verification is adjusted to reflect what experts are sure about, it will wrongly reject 5% of true signatures and wrongly accept 29% of forgeries. If computers were adjusted more strictly, rejecting all signatures which experts have doubts about, the computers would set aside 62% of true signatures, and still wrongly accept 2% of forgeries. Lay people made more mistakes and were doubtful less often, though the study does not report whether their mistakes were to accept more forgeries or reject more true signatures. Voters with short names are at a disadvantage, since experts make more mistakes on signatures with fewer "turning points and intersections." Participants in this study had 10 true signatures to compare to, which is more than most postal ballot verifications have. A more recent study for the US Department of Justice confirms the probabilistic nature of signature verification, though it does not provide numbers.

Online usage

e-mail Electronic mail (email or e-mail) is a method of exchanging messages ("mail") between people using electronic devices. Email was thus conceived as the electronic ( digital) version of, or counterpart to, mail, at a time when "mail" mean ...
newsgroup A Usenet newsgroup is a repository usually within the Usenet system, for messages posted from users in different locations using the Internet. They are discussion groups and are not devoted to publishing news. Newsgroups are technically distin ...
usage, another type of signature exists which is independent of one's language. Users can set one or more lines of custom text known as a
signature block A signature block (often abbreviated as signature, sig block, sig file, .sig, dot sig, siggy, or just sig) is a personalized block of text automatically appended at the bottom of an email message, Usenet article, or forum post. Email and Usenet ...
to be automatically appended to their messages. This text usually includes a name, contact information, and sometimes quotations and
ASCII art ASCII art is a graphic design technique that uses computers for presentation and consists of pictures pieced together from the 95 printable (from a total of 128) characters defined by the ASCII Standard from 1963 and ASCII compliant char ...
. A shortened form of a signature block, only including one's name, often with some distinguishing prefix, can be used to simply indicate the end of a post or response. Some web sites also allow graphics to be used. Note, however, that this type of signature is not related to electronic signatures or
digital signature A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. A valid digital signature, where the prerequisites are satisfied, gives a recipient very high confidence that the message was created b ...
s, which are more technical in nature and not directly understandable by humans.


The signature on a painting or other work of art has always been an important item in the assessment of art. Fake signatures are sometimes added to enhance the value of a painting, or are added to a fake painting to support its authenticity. A notorious case was the signature of
Johannes Vermeer Johannes Vermeer ( , , see below; also known as Jan Vermeer; October 1632 – 15 December 1675) was a Dutch Baroque Period painter who specialized in domestic interior scenes of middle-class life. During his lifetime, he was a moderately su ...
on the fake "Supper at Emmaus" made by the art-forger Han van Meegeren. However, the fact that painters' signatures often vary over time (particularly in the modern and contemporary periods) might complicate the issue. The signatures of some painters take on an artistic form that may be of less value in determining forgeries. If a painting is abstract or ambiguous, the signature can be the only clue to determine which side is the top.


Under British law, the appearance of signatures (not the names themselves) may be protected under
copyright law A copyright is a type of intellectual property that gives its owner the exclusive right to copy, distribute, adapt, display, and perform a creative work, usually for a limited time. The creative work may be in a literary, artistic, educati ...
. Under United States copyright law, "titles, names c... mere variations of typographic ornamentation, lettering, or coloring" are not eligible for copyright;Copyright Basics
", United States Copyright Office. Retrieved 15 March 2011.
however, the appearance of signatures (not the names themselves) may be protected under copyright law.

Uniform Commercial Code

Uniform Commercial Code The Uniform Commercial Code (UCC), first published in 1952, is one of a number of Uniform Acts that have been established as law with the goal of harmonizing the laws of sales and other commercial transactions across the United States through U ...
§1-201(37) of the United States generally defines signed as "using any symbol executed or adopted with present intention to adopt or accept a writing." The Uniform Commercial Code §3-401(b) for negotiable instruments states "A signature may be made (i) manually or by means of a device or machine, and (ii) by the use of any name, including a
trade Trade involves the transfer of goods and services from one person or entity to another, often in exchange for money. Economists refer to a system or network that allows trade as a market. An early form of trade, barter, saw the direct exch ...
or assumed name, or by a word, mark, or symbol executed or adopted by a person with present intention to authenticate a writing."

See also

* Autograph club *'' Autograph Collector Magazine'' * Biometric signature as form of the electronic signature * Builder's signature * Initials * Images of signatures *''
manu propria ' (Latin for ' ignedwith one's own hand'), abbreviated to ''m.p.'' or ''mppr.'' or ''mppria'' is a phrase sometimes used at the end of typewritten or printed documents when there is no handwritten signature. It is typically found just after ...
'' (''m.p.'') * Memorial to the 56 Signers of the Declaration of Independence, includes depicted signatures * Monogram * Round-robin (document), a signed document where the signatures are arranged in a circle * Royal sign-manual * Shakespeare's handwriting *
Signum manus ''Signum manus'' (transl. ''sign of the hand'', sometimes also known as ''Chrismon'') refers to the medieval European practice of signing a document or charter with a special type of monogram or royal cypher. The practice is documented from ...
Tughra A tughra ( ota, طغرا, ṭuġrā) is a calligraphic monogram, seal or signature of a sultan that was affixed to all official documents and correspondence. Inspired by the tamgha, it was also carved on his seal and stamped on the coins minte ...
* Huaya


External links

Why Do We Sign For Things? A Rabbi, A Lawyer And A MasterCard Exec Explain
NPR / Planet Money

at ''Slate''
What is Signature? Signature of 100 famous people
{{Authority control Authentication methods Identity documents Writing Biometrics Articles containing self-references Personal identification Names