In the legal context, a signature can serve a number of functions, each of which can have varying degrees of importance,1 including complying with a legal requirement that something be signed.
The primary evidential function
It is suggested that the primary purpose of a signature serves to provide admissible and reliable evidence that comprises the following elements:
(1) To provide tangible evidence that the signatory approves and adopts the contents of the document.
(2) In so doing, the signatory agrees that the content of the document is binding upon them and will have legal effect.
(3) Further, the signatory is reminded of the significance of the act and the need to act within the provisions of the document.
The nature of the act of signing differs between the application of a manuscript signature and the use of an electronic signature. This is because a manuscript signature, if authentic, is biologically linked to a specific individual, but cryptographic authentication systems bind signatures to individuals by way of software code and procedural mechanisms.
With electronic signatures, the person does not physically sign anything, but causes software to sign electronically using a machine that cannot be relied on to know what document has been signed2 – even when using a biodynamic version of a manuscript signature. This is significant, because the act of signing using an electronic signature has a different symbolic meaning to that of a manuscript signature, and suggests a weaker sense of the involvement of the person in the process of signing, as noted by Professor Chou.3
Secondary evidential functions
A signature can also provide evidence of identification and proof of the following:
(1) Authentication of the identity of the person signing the document. One example would be to reinforce the causal link between the signature and a name printed on a document, such as a name printed on a cheque book or credit card.
(2) The identity of a particular characteristic, or attribute or status of the person, such as a government minister or company director.
(3) That a person signing acknowledges, verifies or witnesses the content of the document, but does not necessarily agree to be bound by it.
(4) That existence of the document provides a record of the intent of the signatory and, in turn, physical evidence of the originality and completeness of the document itself, including the time, date and place of the act of the affixing of the signature to the document.
(5) The authenticity and voluntary nature of the signature of a third party where a person is a witness to the signing of a document, and affixes their own signature as confirmation of this.
(6) Demonstration that the content of the document has not been altered subsequently to the affixing of the signature.
(7) Evidence that the record is a true copy of another record.
(8) Confirmation of the receipt of something, or to obtain access to something.
This function acts to reinforce the legal nature of the document, thereby warning the person affixing their signature that they should take care before committing themselves to the contents of the document.
As a corollary to the cautionary function, the party receiving the document containing a manuscript signature recognizes that the other party affirms the content of the document and they have given their full attention to that content. They can also be assured of the identity of the signatory, and are consequently in receipt of proof of the source and contents of the document. This function is linked to the evidential function.4
The formality of a manuscript signature helps to clarify the point at which a person recognizes the act has become legally significant. Also, the content of the document, by being recorded on a durable form, serves to concentrate the mind on the legally binding nature of the document, thus reducing the risks associated with oral recollections. This function is also linked to the evidential function.
Closely related to the evidential function, a document contained on a carrier manifest in physical form serves as a durable record of the terms of the agreement. It also enables governments to impose taxes on documents and permits audits based on documents that have a physical existence.
1 Lon L. Fuller, ‘Consideration and form’ (1941) 41 Columbia Law Review 799 refers to the evidentiary, cautionary and channelling functions; Ashbel G. Gulliver and Catherine J. Tilson, ‘Classification of gratuitous transfers’ (1941) 51 Yale Law Journal 1; John H. Langbein, ‘Substantial compliance with the Wills Act’ (1975) 88(3) Harvard Law Review 489; Mark Sneddon, ‘Legislating to facilitate electronic signatures and records: exceptions, standards and the impact on the statute book’ (1998) 21 University of New South Wales Law Journal, part 2 II A (i)–(iv), http://www.austlii.edu.au/au/journals/UNSWLJ/1998/59.html; ‘Digital signature guidelines’ (Judicial Studies Board 2000), 3; Jos Dumortier, Patrick Van Eecke and Ilse Anné, The Legal Aspects of Digital Signatures (Leuven: Interdisciplinary Centre for Law and Information Technology 1998), Report 1, Part III, 50; ISTEV, ‘Legal and regulatory Issues for the European trusted services infrastructure – European trusted services’ (2007), para 3; Digital Signature Guidelines (American Bar Association 1996), 49; Adrian McCullagh, Peter Little and William Caelli, ‘Electronic signatures: understand the past to develop the future’ (1998) 21 University of New South Wales Law Journal 56; UNCITRAL Model Law on Electronic Commerce with Guide to Enactment 1996 with additional article 5 bis as adopted in 1998 (New York: United Nations, 1999) paras 48 and 53; UNCITRAL Model Law on Electronic Signatures with Guide to Enactment 2001 (United Nations, New York 2002) para 29; ‘Protections of the acknowledgment’ in ‘A Position on Digital Signature Laws and Notarization’, a position statement from the National Notary Association, September 2000, 3–5; Promoting Confidence in Electronic Commerce: Legal Issues on International Use of Electronic Authentication and Signature Methods (Vienna: United Nations, 2009), 1–8; for a similar overview of the same topic and discussion of the development of signatures, see Lorna Brazell, Electronic Signatures and Identities Law and Regulation (3rd edn, Sweet & Maxwell 2018), 2001–2006.
2 Stephen Mason and Timothy S. Reiniger, ‘“Trust” between machines? Establishing identity between humans and software code, or whether you know it is a dog, and if so, which dog?’ (2015) 21 Computer and Telecommunications Law Review 135.
3 E. Y. Chou, ‘Paperless and soulless: e-signatures diminish the signer’s presence and decrease acceptance’ (2015) 6 Social Psychological and Personality Science 343. Professor Chou also provides further citations.
4 Sneddon, ‘Legislating to facilitate electronic signatures and records’, Part 2 II A (ii).