 # Asymmetrical Cryptography

Cryptography is a technique to hide a data through encryption so that the data is accessible only to the intended person. The Cryptography can be symmetrical and asymmetrical.
For instance, let’s take a lock as an example to understand Symmetric and Asymmetric Cryptography. When the lock has the same key to open and close the lock its called symmetric Cryptography. On the other hand, if there is a different key to close the lock and a different key to unlock it is called Asymmetric Cryptography.
In both the case there is a security but in Asymmetric Cryptography, the security is doubled. Hence asymmetric Cryptography is more secure than Symmetric Cryptography.
In a symmetrical cryptography, both the encryptor and decryptor have identical keys. The data is encrypted by a key through the sender and decrypted by the receiver by the same key. Hence there is a pair of an identical key. Encryption is done to secure the data.
Asymmetrical Cryptography is the method in which a pair of two different but related (corresponding) keys are used to encrypt and decrypt the data. One key is a Public key and other key is the Private key. Now let’s see how Asymmetric Cryptography works
Let’s take an example where Henry a sender of the message wants to send the message to a receiver called Alice. Both Henry and Alice will have a pair of keys called Public Key and Private Key.
To send a message Henry will ask Alice her public key. Using Alice’s public key Henry will encrypt the data and transmit it to Alice who is having the corresponding Private key to decrypt the data. The problem here is that how will Alice determine that the data received has been sent by Henry. This problem arises because Alice had shared her public key. Therefore anyone can send her data using her public key.
To get over this issue Digital signature is used. The sender, Henry, in this case, will use his private key to lock the data and would share his corresponding Public key with. Alice will open the lock with the public key of Henry.
Therefore Asymmetrical Encryption has following advantage
–        Authentication
–        Non-Repudiation
–        Integrity
Authentication- It means the validation of sender of information
Non-Repudiation- It means the sender of information cannot repudiate the information he sent. In other words, the sender cannot disown the information
Integrity- This is achieved via encryption that is done using an algorithmic function