What is a digital signature?

A digital signature serves as a code that verifies the authenticity and integrity of a message. It operates using cryptographic techniques, specifically public key cryptography, ensuring that a document or message’s sender can be authenticated, and that the content has not been altered during transmission.

When a sender creates a digital signature, they generate a unique hash of the document and encrypt it with their private key. The recipient can then decrypt the signature using the sender's public key, allowing them to verify that the message indeed originated from the claimed sender, and that it remains unchanged. This process is crucial in various applications, including secure emails, software distribution, and financial transactions, where ensuring the security and integrity of the information is paramount.

In contrast, methods for encrypting data primarily focus on the confidentiality of the information rather than verifying identity and integrity. Software solutions for managing passwords involve securing user credentials instead of authenticating messages, and protocols for secure communication typically refer to techniques like SSL/TLS that secure data in transit rather than focusing specifically on the verification of the sender and content.