Check out the other chapters in the Communication Series: The Cryptography Handbook
The security of cryptographic applications critically relies on symmetric keys and private keys that are continually kept secret. The method used to keep them secret is also protected.
Two basic types of algorithms are used in modern cryptography—asymmetric key and symmetric key. Asymmetric-key algorithms use a combination of private and public keys while symmetric algorithms use only private ones, commonly referred to as secret keys. The table in the article provides a snapshot of the main features of each algorithmic method.