Electronic signature

An electronic signature, or e-signature, refers to data in electronic form, which is logically associated with other data in electronic form and which is used by the signatory to sign. This type of signature has the same legal standing as a handwritten signature as long as it adheres to the requirements of the specific regulation under which it was created (e.g., eIDAS in the European Union, NIST-DSS in the USA or ZertES in Switzerland).
Electronic signatures are a legal concept distinct from digital signatures, a cryptographic mechanism often used to implement electronic signatures. While an electronic signature can be as simple as a name entered in an electronic document, digital signatures are increasingly used in e-commerce and in regulatory filings to implement electronic signatures in a cryptographically protected way. Standardization agencies like NIST or ETSI provide standards for their implementation (e.g., NIST-DSS, XAdES or PAdES). The concept itself is not new, with common law jurisdictions having recognized telegraph signatures as far back as the mid-19th century and faxed signatures since the 1980s.
Description.
An electronic signature is intended to provide a secure and accurate identification method for the signatory to provide a seamless transaction.
Definitions of electronic signatures vary depending on the applicable jurisdiction. A common denominator in most countries is the level of an advanced electronic signature requiring that:
Electronic signatures may be created with increasing levels of security, with each having its own set of requirements and means of creation on various levels that prove the validity of the signature. To provide an even stronger probative value than the above described advanced electronic signature, some countries like the European Union or Switzerland introduced the qualified electronic signature. It is difficult to challenge the authorship of a statement signed with a qualified electronic signature - the statement is non-repudiable. Technically, a qualified electronic signature is implemented through an advanced electronic signature that utilizes a digital certificate, which has been encrypted through a security signature-creating device and which has been authenticated by a qualified trust service provider.
In contract law.
Since well before the American Civil War began in 1861, morse code was used to send messages electrically by telegraphy. Some of these messages were agreements to terms that were intended as enforceable contracts. An early acceptance of the enforceability of telegraphic messages as electronic signatures came from a New Hampshire Supreme Court case, Howley v. Whipple, in 1869.
In the 1980s, many companies and even some individuals began using fax machines for high-priority or time-sensitive delivery of documents. Although the original signature on the original document was on paper, the image of the signature and its transmission was electronic.
Courts in various jurisdictions have decided that enforceable electronic signatures can include agreements made by email, entering a personal identification number (PIN) into a bank ATM, signing a credit or debit slip with a digital pen pad device (an application of graphics tablet technology) at a point of sale, installing software with a clickwrap software license agreement on the package, and signing electronic documents online.
The first agreement signed electronically by two sovereign nations was a Joint Communiqué recognizing the growing importance of the promotion of electronic commerce, signed by the United States and Ireland in 1998.
Enforceability.
In 1996 the United Nations published the UNCITRAL Model Law on Electronic Commerce. Article 7 of the UNCITRAL Model Law on Electronic Commerce was highly influential in the development of electronic signature laws around the world, including in the US. In 2001, UNCITRAL concluded work on a dedicated text, the UNCITRAL Model Law on Electronic Signatures, which has been adopted in some 30 jurisdictions. The latest UNCITRAL text dealing with electronic signatures is article 9, paragraph 3 of the United Nations Convention on the Use of Electronic Communications in International Contracts, 2005, which establishes a mechanism for functional equivalence between electronic and handwritten signatures at the international level as well as for the cross-border recognition.
Canadian law (PIPEDA) attempts to clarify the situation by first defining a generic electronic signature as "a signature that consists of one or more letters, characters, numbers or other symbols in digital form incorporated in, attached to or associated with an electronic document", then defining a secure electronic signature as an electronic signature with specific properties. PIPEDA's secure electronic signature regulations refine the definition as being a digital signature applied and verified in a specific manner.
In the European Union, EU Regulation No 910/2014 on electronic identification and trust services for electronic transactions in the European internal market (eIDAS) sets the legal frame for electronic signatures. It repeals Directive 1999/93/EC. The current and applicable version of eIDAS was published by the European Parliament and the European Council on July 23, 2014. Following Article 25 (1) of the eIDAS regulation, an advanced electronic signature shall “not be denied legal effect and admissibility as evidence in legal proceedings". However it will reach a higher probative value when enhanced to the level of a qualified electronic signature. By requiring the use of a qualified electronic signature creation device and being based on a certificate that has been issued by a qualified trust service provider, the upgraded advanced signature then carries according to Article 25 (2) of the eIDAS Regulation the same legal value as a handwritten signature. However, this is only regulated in the European Union and similarly through ZertES in Switzerland. A qualified electronic signature is not defined in the United States.
The U.S. Code defines an electronic signature for the purpose of US law as "an electronic sound, symbol, or process, attached to or logically associated with a contract or other record and executed or adopted by a person with the intent to sign the record." It may be an electronic transmission of the document which contains the signature, as in the case of facsimile transmissions, or it may be encoded message, such as telegraphy using Morse code.
In the United States, the definition of what qualifies as an electronic signature is wide and is set out in the Uniform Electronic Transactions Act ("UETA") released by the National Conference of Commissioners on Uniform State Laws (NCCUSL) in 1999. It was influenced by ABA committee white papers and the uniform law promulgated by NCCUSL. Under UETA, the term means "an electronic sound, symbol, or process, attached to or logically associated with a record and executed or adopted by a person with the intent to sign the record." This definition and many other core concepts of UETA are echoed in the U.S. ESign Act of 2000. 48 US states, the District of Columbia, and the US Virgin Islands have enacted UETA. Only New York and Illinois have not enacted UETA, but each of those states has adopted its own electronic signatures statute.As of June 11, 2020, Washington State Office of CIO adopted UETA
Legal definitions.
Various laws have been passed internationally to facilitate commerce by the use of electronic records and signatures in interstate and foreign commerce. The intent is to ensure the validity and legal effect of contracts entered into electronically. For instance,
Usage.
In 2016, Aberdeen Strategy and Research reported that 73% of "best-in-class" and 34% of all other respondents surveyed made use of electronic signature processes in supply chain and procurement, delivering benefits in the speed and efficiency of key procurement activities. The percentages of their survey respondents using electronic signatures in accounts payable and accounts receivable processes were a little lower, 53% of "best-in-class" respondents in each case.
Technological implementations (underlying technology).
Digital signature.
Digital signatures are cryptographic implementations of electronic signatures used as a proof of authenticity, data integrity and non-repudiation of communications conducted over the Internet. When implemented in compliance to digital signature standards, digital signing should offer end-to-end privacy with the signing process being user-friendly and secure. Digital signatures are generated and verified through standardized frameworks such as the Digital Signature Algorithm (DSA) by NIST or in compliance to the XAdES, PAdES or CAdES standards, specified by the ETSI.
There are typically three algorithms involved with the digital signature process:
The process of digital signing requires that the signature generated by both the fixed message and private key can then be authenticated by its accompanied public key. Using these cryptographic algorithms, the user's signature cannot be replicated without having access to their private key. A secure channel is not typically required. By applying asymmetric cryptography methods, the digital signature process prevents several common attacks where the attacker attempts to gain access through the following attack methods.
The most relevant standards on digital signatures with respect to size of domestic markets are the Digital Signature Standard (DSS) by the National Institute of Standards and Technology (NIST) and the eIDAS Regulation enacted by the European Parliament. OpenPGP is a non-proprietary protocol for email encryption through public key cryptography. It is supported by PGP and GnuPG, and some of the S/MIME IETF standards and has evolved into the most popular email encryption standard in the world.
Biometric signature.
Electronic signature may also refer to electronic forms of processing or verifying identity through use of biometric "signatures" or biologically identifying qualities of an individual. Such signatures use the approach of attaching some biometric measurement to a document as evidence. Biometric signatures include fingerprints, hand geometry (finger lengths and palm size), iris patterns, voice characteristics, retinal patterns, or any other property of a human body. All of these are collected using electronic sensors of some kind. Because each of these physical characteristics has claims to uniqueness among humans, each is to some extent useful as a signature.
Biometric measurements of this type are useless as passwords, because they can't be changed if compromised. However, they might be serviceable, except that to date they have been so easily deceived that they can carry little assurance that the person who purportedly signed a document was actually the person who did. For example, a replay of the electronic signal produced and submitted to the computer system responsible for 'affixing' a signature to a document can be collected via wiretapping techniques. Many commercialy available fingerprint sensors have low resolution and can be deceived with inexpensive household items (for example, gummy bear candy gel). In the case of a user's face image, researchers in Vietnam successfully demonstrated in late 2017 how a specially crafted mask could beat Apple's Face ID on iPhone X.