Digital signature definition is a requisite of the digital entity that is reached as a result of cryptographic manipulation with information using a private signing key and verifying the absence of distortion of information in an electronic document since the formation of the signature (integrity), the belonging of the signature to the owner of the signature key certificate (authorship), and in the case of successful validation, to confirm the fact of signing of an electronic document (non-repudiation). Sometimes, a process of implementing such property is also referred to as digital signature.
Digital signature is unique for every document it was used for to sign. A document that was signed with a digital signature is specifically encrypted in a way that leaves an opportunity for users, other than the document’s author, to read it. However, this encryption makes the document easily validatable in terms of authorship and integrity by making it unchangeable. The method comes in handy when some document or file has to be transferred via insecure network to ensure that the receiver of the document won’t get an altered version.
Digital signature can be used not only to protect the document's contains from changing by someone apart from its author but also for a number of other purposes. For example, digital signature can be used to develop digital signature certificate, visibly showing its reader that the document was made by particular entity.
Digital signature can also be used to approve a document. For example, some corporate decision needs to be approved by several top-managers. When the decision is generated in a digital form, it is certified with a digital signature by its author showing other readers that the document was made by the right person and was not changed while transferring. Then, it could be approved by every top manager, each leaving a visible signature in it. When all the managers are done, the document is certified, validated and approved.
Some digital signatures are not visible in terms of particular person who validated a document. It means that the document can be signed anonymously. Users will see a visual signal representing the fact that the document is signed and wasn’t changed while transferring, but won’t see the name or other ID of its author.
Digital signature software
Digital signature software is mostly an element of cryptography-based products (libraries, suites, digital signature apps). The software is often implemented in business, government and sensible information transferring. It is also commonly used to protect financial transactions, software distribution and digital contracts. The digital signature algorithm mostly goes as following:
- Firstly, private key is generated with some mathematical algorithm. This key is intended to be owned exclusively by the author of a signed document.
- Then, public key is generated - a key that will be later obtained by other users.
- After that, the document is signed, meaning it can be changed without invalidating the signature only when a user has this document’s private key.
- Users that want to get permission to obtain the signed entity will buy it if its distributed on commercial terms or download it if it’s free. When they get access to the document, they also receive a public key.
- Public key allows the user to read the document or to use it if it’s some software it but does not allow them to change it.
There are multiple solutions designed specifically for digital signature. They differ in their functional and security level. However, there are plenty of well-made enterprise-grade solutions for digital signature, for example:
- Fluix Sign
- eSign Genie
- Adobe Document Cloud
While talking about the legal implications of digital signature it is important to remember what is a digital signature in the legal terms. Digital signature is a process and a scheme that leads to a document being electronically signed. Electronic signature is a broader term that defines digital data being connected with some other data that acts like a signature (is unalterable, unrepeatable and unique). Despite electronic signature being more secure than an ink signature, it is yet to become legally acclaimed in most countries.
However, it is common for the advanced nations with developed economies to use electronic signature as a legally-approved way to sign various documents. Such countries have a well-established legal framework and specific regulation that provide sets standards, technologies and schemes that are legitimate to use for digital signature and make electronic signatures made with it covered by the rule of law.