A digital signature is a mathematical scheme for demonstrating the authenticity of a digital message or documents. It is a process that guarantees that the contents of a message have not been altered in transit. A valid digital signature gives a recipient reason to believe that the message was created by a known sender, that the sender cannot deny having sent the message (authentication and non-repudiation), and that the message was not altered in transit (integrity).
Digital signatures are commonly used for software distribution, financial transactions, and in other cases where it is important to detect forgery or tampering. It can be considered as a numerical value that is represented as a sequence of characters. The creation of a digital signature is a complex mathematical process that can only be created by a computer. To create a digital signature, signing software, such as an email program, creates a one-way hash of the electronic data to be signed. They are used in e-commerce, software distribution, financial transactions and other situations that rely on forgery or tampering detection techniques.