Digital signatures are a cryptographic technique used to validate the authenticity and integrity of digital messages or documents. They provide a way to ensure that a message has not been altered in transit and confirm the identity of the sender, much like a handwritten signature does for paper documents. The process involves the use of a private key to create a unique signature for the document, which can then be verified by anyone with access to the corresponding public key. This technology is widely used in various applications, including blockchain, email security, and software distribution to enhance security and trust in digital communications.