A digital signature is an electronic equivalent of a physical signature. Just like the way a signature in a paper authenticates the signer, the digital signature also confirms the authenticity of the owner. Besides, it ensures that integrity of the data and non-repudiation. Non-repudiation means that the sender cannot later deny that he did not send the message. So, if you have a digitally signed copy of a document, you can say that the sender of the document is authentic and the data in the document has not been modified by any intruders. Therefore, a digital signature has three purposes: [Read more…]