Question

3. Public Key Cryptography involves the use of two keys: a public key and a private key. Explain the use of each key

Answer 1

PUBLIC KEY CRYPTOGRAPHY:

It is a cryptographic algorithm, also known as asymmetric cryptography which uses both Private Key and Public Key. These Keys are nothing but randomly generated numbers.

(i) Public Key: The name itself states the behaviour of the key. The Public Key is made available to the public that can be used by the users.

(ii) Private Key: The Private Key is confidential and is not known by others except the owner.

Both the keys are related to each other mathematically, if the data is encrypted by Public key then the data can only be decrypted by its corresponding Private Key (Vice Versa). The Private Key only has the ability to decrypt the data.

Example: Person ‘A’ wants to send sensitive data to Person ‘B’ and he wants it to be secure from others, Person ‘A’ encrypts the data with the Public Key and sends it to Person ‘B’. Person ‘B’ has a corresponding Private Key to Decrypt it. Person ‘B’ can now decrypt it and use it.

There can be a chance that some Person ‘C’ steals the data before the data is delivered to the Person ‘B’. If this happens, still Person ‘C’ cannot read or use the data as it is encrypted and can only be decrypted by the Private Key which is only accessible to Person ‘B’.

Hence, Both keys are required to encrypt or decrypt the data in order to send/receive the sensitive data.