ECDSA, or Elliptic Curve Digital Signature Algorithm, is a cryptographic technique used to ensure the authenticity and integrity of digital messages. It relies on the mathematics of elliptic curves, which allows for smaller key sizes compared to traditional methods like RSA, while still providing strong security. This makes ECDSA particularly efficient for devices with limited processing power. In practice, ECDSA generates a unique digital signature for a message, which can be verified by anyone with the corresponding public key. This process helps prevent forgery and ensures that the message has not been altered, making it widely used in applications like blockchain and secure communications.