Public key Algorithms in Cryptography

Asymmetric cryptography is a branch of cryptography where a secret key can be divided into two parts, a public key and a private key. The public key can be given to anyone, trusted or not, while the private key must be kept secret , to encrypt and decrypt a message and protect it from unauthorized access or use. A public key is a cryptographic key that can be used by any person to encrypt a message so that it can only be deciphered by the intended recipient with their private key. A private key — also known as a secret key — is shared only with key’s initiator.

Asymmetric cryptography has two primary use cases: authentication and confidentiality. Using asymmetric cryptography, One key, the Public Key, is used for encryption and the other, the Private Key, is for decryption. As implied in the name, the Private Key is intended to be private so that only the authenticated recipient can decrypt the message.

1. The RSA Algorithm

2. The Diffie-Hellman Algorithm

3. The Elliptical Wave Theory Algorithm

RSA Algorithms –

This is probably the most famous and widely used Asymmetric Cryptography Algorithm. This algorithm can be used for encrypting and signing data. The encryption and signing processes are performed through a series of modular multiplications.

The basic RSA algorithm for confidentiality can be explained as below.

The RSA Algorithm uses the power of prime numbers to create both the Public Keys and the Private Keys. However, using such large keys to encrypt large amounts of information and data are totally infeasible, from the standpoint of the processing power and Central Server resources.

Once the receiving party obtains their Ciphertext from the sending party, the Private Key which has been generated by the Symmetric Cryptography Algorithms is then decrypted. From this point, the Public Key that was generated by the RSA Algorithm can then be subsequently used to decrypt the rest of the Ciphertext.

The Diffie-Hellman Algorithm

Its main objective is to find a solution for sending the Public Key/Private Key combination through a secure channel.

How it works ?

1. The receiver has possession of the Public Key and the Private Key which has been generated, but this time, they have been created by the Diffie-Hellman Algorithm.

2. The sender receives the Public Key generated by the receiving party and thus uses the DH Algorithm to generate another set of Public Keys. But it is temporary.

3. The sender now takes this newly created, temporary Public Key/Private Key combination sent by the receiver to generate a random, secret number-this becomes known specifically as the “Session Key.”

4. The sender uses this newly established session key to encrypt the Ciphertext message and sends this forward to the receiver with the Public Key which has been temporarily generated.

5. When the receiver finally receives the Ciphertext message from the sender, the session key can now be derived mathematically.

6. Once the above step has been completed, the receiving party can now decrypt the rest of the Ciphertext message.

The Elliptical Wave Theory Algorithm

This can be used to encrypt a very large amount of data, and its main advantage is that it is very quick.