What is Public Key Cryptography?

John Spacey, updated on November 27, 2016

Public key cryptography is any encryption system based on pairs of public and private keys. Public keys are published to the world and are used to encrypt messages for a receiver. Such messages can only be decrypted with the receiver's private key.

Key Generation

Public key cryptography relies on algorithms for generating public/private key pairs such that it is computationally infeasible to determine a private key from a public key.

Key Exchange

The primary advantage of public key cryptography is that it doesn't require a secure exchange of secrets to work. This is ideal for applications such as web browsing where a large number of clients and services need to connect to each other securely.

Public key cryptography tends to be computationally complex. Therefore, it is often used to exchange symmetric keys that are used for one session and then discarded. This is done because symmetric encryption is generally faster.

Overview: Public Key Cryptography
Type	Cryptography
Definition	Encryption based on pairs of public and private keys whereby any sender can encrypt a message with a public key that can only be read with the corresponding private key.
Value	Enables encryption between a large number of clients and services without the need to share private keys.
Also Known As	Public Key Encryption Asymmetric Cryptography
Related Concepts	Nonce Information Security Cryptography