What is a digital signature primarily used for?

A digital signature is primarily used to provide data integrity, which assures that the data has not been altered in transit and is authentic. When a sender uses a digital signature, it involves encrypting a hash of the data with their private key. This ensures that anyone receiving the data can verify its integrity through the corresponding public key. If the data has been changed in any way, the hash values will differ, indicating that the signature is invalid, and thus, allowing the recipient to conclude that the data may not be trustworthy.

This process plays a crucial role in various applications, especially in cybersecurity and secure communications, where confirming that messages have not been tampered with is essential. Digital signatures also support non-repudiation, meaning the sender cannot deny the authenticity of the message they sent.

In contrast, the other options do not capture the fundamental purpose of a digital signature. While simplifying data storage, enhancing network performance, or facilitating direct device communication are important tasks in network defense or data management, they do not pertain to the primary function of a digital signature in ensuring data integrity.