Digital Signature

A digital signature is an electronic signature that can be used to authenticate the identity of the sender of a message or the signer of a document. The basic idea behind digital signature is the same as handwritten signature. A digital signature doesn’t involve signing something with a pen and paper then sending to the receiver. But like a paper signature, it attaches the identity of the signer to a transaction. When transferring important documents it is often necessary to certify in a reliable way that who is actually the sender of a given document. So we can certify the origin of documents and files is by using the Digital Signature. Whenever we need to authenticate the data or messages and any kind of information transfer in any network we require verification of this data that it is coming from authorized user so for this confirmation we can use a security mechanism that is called digital signature. The digital signature cannot be copied, tampered, or altered because it has some private keys based on content. Digital Signatures are messages that identify and authenticate a particular person as the source of the message and indicate such person’s approval of the information contained in the message. To generate digital signature we use cryptography technique combine with a hash function and a proper algorithm which provides a public and private key pair .A public key can be used to check digital signatures, created with the corresponding private key, as well as for encrypting documents that can then be decrypted only by the owner of the corresponding private key. The public keys are not secret to anybody. The private key is a number known only to its owner. With his or her private key, a person can sign documents and decrypt documents that are encrypted with corresponding public key. So digital signature may resemble with a unique password for electronic