A digital signature is a cryptographic technique used to verify the authenticity and integrity of digital messages or documents. It serves as an electronic equivalent of a handwritten signature or stamped seal, offering a higher level of security by ensuring that the message or document has not been altered and confirming the identity of the sender.

Digital signatures rely on public key cryptography, where two keys are used: a private key and a public key. The private key is used to create the signature, while the public key is used by the recipient to verify it. When a digital signature is applied, it generates a unique code based on the content of the message or document, making it impossible to forge without access to the private key.

Key benefits of digital signatures include:

1. Authentication: Ensures that the sender of a message or document is who they claim to be.
2. Integrity: Verifies that the content of the message or document has not been tampered with after it was signed.
3. Non-repudiation: Prevents the sender from denying that they signed the document, as only their private key could have created the signature.

Digital signatures are widely used in various applications, including securing email communications, signing contracts, and authenticating software. They are a critical component in ensuring trust and security in digital transactions and communications.