What is a Digital Signature?

A digital signature is indeed a digital version of a traditional signature. It serves as a means of validating the authenticity and integrity of a message, software, or digital document. This technology utilizes a combination of hashing and public key cryptography, allowing the sender of a message to create a unique code that is attached to the message. This code confirms that the message was not altered during transit, providing assurance that it originated from the legitimate sender.

In contrast to physical signatures, which are often subject to forgery and require trust in the individual presenting the document, digital signatures employ cryptographic techniques to ensure security and authenticity. The recipient of a digitally signed document can verify the signature using the sender's public key, ensuring both the integrity and the identity of the sender.

The other options do not accurately represent what a digital signature is. A physical stamp for documents refers to a tangibility that does not apply in the digital realm, while a password-protected file is about securing access rather than signing or verifying authenticity. Lastly, a type of encryption key deals with the broader concept of securing information rather than the specific function of a digital signature in validating identity and integrity.