Public key encryption is a method of encrypting data that uses two different keys: a public key and a private key. The public key is shared with anyone who wants to send you an encrypted message, while the private key is kept secret and is used to decrypt messages that have been encrypted with the corresponding public key. This allows for secure communication between parties without the need to share a secret key beforehand.
One example of public key encryption is the RSA algorithm. It is a widely used method for secure data transmission, and it is based on the fact that it is computationally infeasible to factorize a large composite number (the product of two prime numbers) into its prime factors. In the RSA algorithm, the sender uses the recipient's public key to encrypt the message, and the recipient uses their private key to decrypt it. This allows for secure communication without the need for the sender and recipient to share a secret key beforehand.
There are two main types of public key encryption: symmetric-key encryption and asymmetric-key encryption. In symmetric-key encryption, the same key is used to encrypt and decrypt the data. This means that the sender and recipient must share the same secret key in order to communicate securely. In asymmetric-key encryption, also known as public-key encryption, different keys are used for encryption and decryption. The public key is shared with anyone who wants to send an encrypted message, while the private key is kept secret and is used to decrypt the message. This allows for secure communication without the need to share a secret key beforehand.
There are six main elements of public key encryption: