views updated Jun 27 2018


A mark or sign made by an individual on an instrument or document to signify knowledge, approval, acceptance, or obligation.

The term signature is generally understood to mean the signing of a written document with one's own hand. However, it is not critical that a signature actually be written by hand for it to be legally valid. It may, for example, be typewritten, engraved, or stamped. The purpose of a signature is to authenticate a writing, or provide notice of its source, and to bind the individual signing the writing by the provisions contained in the document.

Because a signature can obligate a party to terms of a contract or verify that the person intended to make a last will and testament, the law has developed rules that govern what constitutes a legally valid signature. The internet and other forms of telecommunication have created the need to transact legally binding agreements electronically. Almost all states have passed laws that recognize the validity of "digital signatures."

Requisites and Validity

When an instrument must be signed, it is ordinarily adequate if the signature is made in any commonly used manner. Variations between the signature and the name appearing in the body of the instrument do not automatically invalidate the instrument.

In the absence of a statutory prohibition, an individual can use any character, symbol, figure, or designation he wishes to adopt as a signature, and if he uses it as a substitute for his name, he is bound by it. For example, if a contract refers to "William Jones" but Jones signs his name "Bill Jones," the contract is still enforceable against him. An individual can also use a fictitious name or the name of a business firm. A signature might also be adequate to validate an instrument even if it is virtually illegible. The entire name does not have to be written, and the inclusion of a middle name is not significant.

An individual satisfies the signing requirement when someone who has been duly authorized to sign for him does so. In the event a statute mandates an instrument be signed in person, the signature must be made in the signer's own hand or at his request and in his presence by another individual.

In a situation where an individual intends to sign as a witness but instead inadvertently signs the instrument in the place where the principal is to sign, the fact that he should have signed as a witness can be shown. Conversely when a signer intends to sign as a principal but instead signs in the place for a witness, that fact can also be shown.

Abbreviations, Initials, or Mark

In situations that do not require a more complete signature, an instrument can be properly signed when the initial letter or letters of the given name or names are used together with the surname (J. Doe), when only the full surname is used (Doe), when only the given name is used (John), or even when only the initials are used (J. D.).

A mark is ordinarily a cross or X made in substitution for the signature of an individual who is unable to write. In the absence of contrary statutory provision, a mark can be used by an individual who knows how to write but is unable to do so because of a physical illness or disability. A mark has the same binding effect upon the individual making it as does a signature. In some statutes a signature is defined as including a mark made by an individual who is infirm or illiterate.

Generally the name of the person who makes his mark can be written by anyone, and the mark is not necessarily invalidated because the individual writing the name accompanying the mark misspells the name. In the absence of a statute that requires a name to accompany the mark, the validity of the mark as a signature is not affected by the fact that a name does not accompany it.

When a mark is used as a signature, it can be put wherever the signature can appear. When there is a requirement that the name must accompany the mark, the fact that the mark and the name are not in immediate proximity does not invalidate the mark.

Certain statutes mandate that a witness must attest to a signature made by a mark. Under such statutes, if the mark is not properly witnessed, the instrument is not signed and is legally ineffective. These laws were enacted to prevent fraud, because it is difficult, if not impossible, to later determine if the alleged signer actually made the mark.

Hand of Party or Another

A signature can be written by the hand of the purported signer, either through the signer's unaided efforts or with the aid of another individual who guides the signer's pen or pencil. In cases when the maker's hand is guided or steadied, the signature is the maker's act, not the act of the assisting individual.

A signature can generally be made by one individual for another in his presence and at his direction, or with his assent, unless prohibited by statute. A signature that is made in this manner is valid, and the individual writing the name is regarded merely as an instrument through which the party whose signature is written exercises personal discretion and acts for himself.


Ordinarily a signature can be affixed in a number of different ways. It can be hand written, printed, stamped, typewritten, engraved, or photographed. This allows, for example, a business to issue its payroll checks with the signature of its financial officer stamped rather than handwritten.

Digital Signatures

The computer and telecommunications have changed how work is done and how it is exchanged. Both business and the legal system have begun to explore ways of using the Internet and other forms of electronic communication to transact work. Court systems cannot permit the electronic filing of legal documents, however, unless the documents have been authenticated as coming from the sender. Similarly, businesses will not enter into contracts using the Internet or e-mail unless they can authenticate that the other contracting party actually made the agreement. Computers and digital scanners can reproduce handwritten signatures, but they are susceptible to forgery.

A solution has been the legal recognition of "digital signatures." The majority of states have enacted statutes that allow digital signatures in intrastate transactions. In 2000, President bill clinton signed into law the Electronic Signatures in Global and National Commerce Act, Pub. L. No. 106-229, 114 Stat. 464, also called the E-Sign Act, which essentially validates electronic contracts in interstate and foreign commerce. The act does not apply to certain types of documents, including wills, divorce notices, and documents that are associated with court proceedings.

A digital signature is based on cryptography, which uses mathematical formulas, or algorithms, to scramble messages. Using encryption and decryption software, the sender can scramble the message and the recipient can unscramble it. To affix a digital signature to an electronic document, a signer must obtain electronic "keys." The keys are assigned in pairs: a private key and a public key.

A person creates his keys using a software program. The digital signature is affixed to the electronic document using the private key. The "signer" types in a password, similar to a personal identification number for an automatic teller machine. The private key then generates a long string of numbers and letters that represent the digital signature, or public key. The recipient of the message runs a software program using this public key to authenticate that the document was signed by the private key and that the document has not been altered during transmission.

It is mathematically infeasible for a person to derive another person's private key. The only way to compromise a digital signature is to give another person access to the signature software and the password to the private key.

further readings

Hurewitz, Barry J., and Bipassa Nadon. 2002. "Electronic Signature Standards Create Contracting Options." Journal of Internet Law 6 (September).

Saunders, Margot. 2003. "A Case Study of the Challenge of Designing Effective Electronic Consumer Credit Disclosures: The Interim Rule for the Truth in Lending Act." North Carolina Banking Institute 7 (April).

Tinnes, Christy. 1997. "Digital Signatures Come to South Carolina: The Proposed Digital Signature Act of 1997." South Carolina Law Review 48 (winter).

Whitaker, R. David. 2003. "An Overview of Some Rules and Principles for Delivering Consumer Disclosures Electronically." North Carolina Banking Institute 7 (April).

White House. Office of the Press Secretary. 2000. "Eliminating Barriers to Electronic Commerce While Protecting Consumers: The Electronic Signatures in Global and National Commerce Act." June 30.

Wims, Michael D. 1995. "Law and the Electronic Highway: Are Computer Signatures Legal?" Criminal Justice 10 (spring).




views updated May 18 2018

1. A collection of symbols intended to be associated with sets and with functions on and elements from the sets. Signatures provide names for the carrier sets, operations, and constants of algebras. They are central in the precise treatment of the syntax of many computer science concepts, including (a) abstract data types, (b) algebraic specifications, and (c) classes, modules, and objects. Typically, headers of modules are signatures. The specification of an Ada package is in effect a signature.

In its simplest form a signature is a set Σ of symbols with, for each σ ∈ Σ, a natural number ρ(σ) called the arity of σ. A Σ-algebra consists of a set A (called the carrier of the algebra) together with, for each σ ∈ Σ, an n-argument function over A, where n = ρ(σ). As an example, suppose Σ = {`zero', `one', `plus', `times'} with ρ(`zero') = ρ(`one') = 0 and ρ(`plus') = ρ(`times') = 2

Then one Σ-algebra results from taking the set of all integers as carrier, and associating the number 0 with `zero', 1 with `one', addition with `plus', and multiplication with `times'. As indicated by ρ, addition and multiplication are 2-argument functions while zero and one, being constants, expect no arguments and their arity is 0.

It is important to realize that the above example describes only one possible Σ-algebra. For example, the carrier could be the real numbers; or, perversely multiplication could be associated with `plus' and addition with `times'; equally sets could be considered instead of numbers, associating, say, union and intersection with `plus' and `times'. The point is that an algebra can involve arbitrary sets and arbitrary functions: any choice is as much an algebra as any other and it need not reflect in any obvious way the names chosen for the symbols in the signature. Indeed the whole point of signatures is to make a distinction between the names and symbols and their possible interpretations.

In computer science the more complex notion of many-sorted signature is used. This allows algebras to have many carriers. A signature now, in addition to function symbols, includes a set of sorts. These are symbols that, in an algebra, are associated with carrier sets. Instead of a natural number, ρ(σ) is a sequence of sorts indicating which sets the arguments come from, together with an additional sort giving the set in which the result lies.

Signatures are often displayed as shown in the diagram. Here real numbers and Booleans are equipped with their usual operations.

2. That part of an e-mail message in which the originator states his or her identity and claims authenticity.

3. A bit pattern believed to be specific to a particular program and used to identify virus programs or unlicensed copies of proprietary software.

4. See signature analysis.


views updated May 29 2018

sig·na·ture / ˈsignəchər; -ˌchoŏr/ • n. 1. a person's name written in a distinctive way as a form of identification in authorizing a check or document or concluding a letter. ∎  the action of signing a document: the license was sent to the customer for signature. ∎  a distinctive pattern, product, or characteristic by which someone or something can be identified: the chef produced the pâté that was his signature | [as adj.] his signature dish. 2. Mus. short for key signature or time signature.3. Printing a letter or figure printed at the foot of one or more pages of each sheet of a book as a guide in binding. ∎  a printed sheet after being folded to form a group of pages.4. the part of a medical prescription that gives instructions about the use of the medicine or drug prescribed.


views updated May 17 2018

signature. A ‘sign’ placed at the opening of a comp. or of a section of a comp., indicating the key (key signature) or the value of the beat and the no. of beats in each measure (time signature). The key signature consists of one or more sharps or flats; the time signature usually of figures resembling a fraction, e.g. 3/4.


views updated May 08 2018

signature The characteristics of geophysical anomalies within a region or along a profile. It is often based on Fourier or power-spectrum analyses of either gravity (gravity signature) or magnetic (magnetic signature) residual anomalies.