Introduction to Digital Signatures

An overview of digital signatures and understanding the difference between a digital signature and an electronic signature.

Introduction to digital signatures

An electronic signature is an electronic symbol attached to a contract or other record, used by a person with an intent to sign. In contrast, digital signatures guarantee that an electronic document is authentic.

The difference between digital signatures and electronic signatures is largely found in the method of identifying businesses and signers. Digital signatures embed what's called "Public Key Infrastructure" (PKI) into the signing process as a way to identify both the party requesting a signature and the party providing one.


What is a 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 strong reason to believe that the message was created by a known sender (authentication) and that the message was not altered in transit (integrity).

Digital signatures are a standard element of most cryptographic protocol suites and are commonly used for software distribution, financial transactions, contract management software, and in other cases where it is important to detect forgery or tampering. Digital signatures are often used to implement electronic signatures, which includes any electronic data that carries the intent of a signature, but not all electronic signatures use digital signatures.

Digital signatures employ asymmetric cryptography. In many instances they provide a layer of validation and security to messages sent through a non-secure channel: Properly implemented, a digital signature gives the receiver reason to believe the message was sent by the claimed sender. Digital signatures are equivalent to traditional handwritten signatures in many respects, but properly implemented digital signatures are more difficult to forge than the handwritten type.

Digital signature schemes, in the sense used here, are cryptographically based and must be implemented properly to be effective. Digital signatures can also provide non-repudiation, meaning that the signer cannot successfully claim they did not sign a message, while also claiming their private key remains secret. Further, some non-repudiation schemes offer a timestamp for the digital signature, so that even if the private key is exposed, the signature is valid.


Understanding the terms

Digital signatures are a mechanism by which transactions are authenticated and secured. They involved the use of a unique, authentication key visible only to the sender and the receiver of a transaction.

Electronic signatures are used in place of physical signatures to bring in authentication in a consistent manner. Electronic signatures often come with a legal standing based on the geography of operation.

The main difference between digital signatures and electronic signatures is where they are used. An electronic signature is mainly used to sign the electronic documents where the signatory has an intention to sign. Whereas digital signatures are used to secure the documents as a way to verify the authenticity of the documents.