Digital Signature

The use of a mathematical technique to verify that some information legitimately came from someone in possession of a specific cryptographic key (usually linked to their identity), and to confirm that it wasn't altered in any way. Digital signatures may be used with software downloads to make sure that the software you're installing is the same as the official version, and that nobody has tampered with it. When information isn't protected by a digital signature, an attacker could change the contents of what someone wrote or published, and there wouldn't be a technical means to detect that this happened.