Asymmetric cryptography

Asymmetric cryptography refers to a type of cryptography where the key that is used to encrypt the data is different from the key that is used to decrypt the data. These keys are called private and public keys, respectively, which why asymmetric cryptography is also known as public key cryptography. It uses both public and private keys to encrypt and decrypt data, respectively. Various asymmetric cryptography schemes are in use, including RSA (named after its founders, Rivest, Shamir, and Adelman), DSA (Digital Signature Algorithm), and ElGamal encryption.

An overview of public-key cryptography is shown in the following diagram:

Figure 4.1: Encryption/decryption using public/private keys

The preceding diagram illustrates how a sender encrypts data P using the recipient's public key and encryption function E, and produces an output encrypted data C, which is then transmitted over the network to the receiver. Once it reaches the receiver...