Digital Signature is a type of security measure that is used to validate the authenticity and integrity of a message, software or digital document.
A digital signature is a type of asymmetric cryptography that is used for sending messages through an insecure channel. The signature is used to determine that the message is actually sent by the person who claims to send it and also that the message has not been tampered with.
Digital signatures use the process of encryption ensure authentication. Encryption includes taking all the data that one computer is sending to another and encoding it into a form that only the other computer will be able to decode. Passwords are the most common and simplest form of digital signatures that are used for authentication. Each username is given a password, so if the computer prompts asking for a password, the password and username are checked against a secure file. If they do not match, the user is denied further access.
There are two keys when it comes to digital signatures. Public key and private key are used to create digital signatures. Public key is a combination of public key and private key. The public key is an encryption that is given by the host computer to any other computer that wishes to communicate with it. To decode an encrypted message, a computer must use the public key provided by the originating computer and its own private key.
Private Key is the secret code that allows a computer to encrypt a packet of information before it is sent over the network to the other computer. In order for the computers to talk to each other on that same network, they must have the key installed on them. A best example would be something like a coded language. So, if two people wish create a code that each letter of the alphabet represents the letter on the end. So, A would Z, B would be Y, C would be X and so on. Now, if one person sends a letter written in this manner to the second person and he does not know the code, he won’t be able to understand what the letter is. This is the manner in which a private key works.
Another example includes an e-mail. If one wants to send another person an e-mail, they can do so by using the e-mail address. Now, that can be considered as the public key. Anyone can send that person an email by using the email address. However, no one can access the email account, unless they have a password (i.e. the private key).
Public keys and private keys are often based on a hash value, which is computed from a base input number using a hashing algorithm. The hashing algorithm encrypts the data. The encrypted hash – along with other information, such as the hashing algorithm – is the digital signature.