What is a digital signature?

A digital signature is a means of electronically signing a document that provides a way to verify the authenticity and integrity of a message or document. It relies on cryptographic techniques to ensure that the sender's identity is confirmed and that the content has not been altered in transit. When someone digitally signs a document, they create a unique code that is tied to both the document and the signer, making it extremely difficult to forge without the appropriate keys.

This method enhances security in digital communications by allowing recipients to authenticate who sent the document and to ensure that it hasn't been tampered with. Digital signatures are commonly used in various applications, such as secure email communications, software distribution, and financial transactions. The technical foundation of digital signatures often involves hashing and asymmetric encryption, which further ensures that the signature is unique and secure.

The other options, while related to the concept of signatures, do not accurately capture the essence of a digital signature. For example, encrypting data broadly pertains to making data unreadable without a key, not specifically about signing. A physical signature is a traditional handwritten mark and does not involve electronic methods. An electronically forged signature implies deceit, which contradicts the fundamental purpose of digital signatures, which is to provide authenticity and security.