A digital signature, also known as a public key digital signature, is a string of digits that can only be generated by the sender of the information and cannot be forged by anyone else. This string of digits also serves as valid proof of the authenticity of the sender’s message. It is similar to a conventional physical signature written on paper but is implemented using public key encryption technology to authenticate digital information. A set of digital signatures usually defines two complementary operations: one for signing and another for verification. Digital signatures are an application of asymmetric key encryption technology combined with digital digest technology.