Write shorts notes on Digital Signature.

This method is used to authenticate the sender of a message. For sign a message, the sender encrypts the message by using a key identified only to the sender. And the recipient utilizes the inverse function to decrypt the message.

The recipient recognizes who sent the message since only the sender has the key required to present the encryption. To make sure that encrypted messages are not copied and resent later, the original message can hold date and time this was sent.

A public key system can be utilized to give a digital signature.

For sign a message, a user encrypts the message by using his or her, own private key. Just to verify the signature, the recipient seems up the user's public key; only a user can encrypt a message which can be encoded along with the public key.