How it Works
You can think of symmetric encryption as a padlocked box containing sensitive information being sent from Bob to John. Both parties hold identical keys that are able to unlock the box, also known as secret keys. Bob locks the box with his key, and as John is the only other person that holds a key to unlock the box, only he can unlock and view its contents.
Common Names & Use-Cases
Symmetric encryption is also known as shared-key, single-key, secret-key, private-key or one-key encryption.
Common examples of symmetric encryption include:
AES (Advanced Encryption Standard): adopted by the U.S. government in 2002, AES was approved by the NSA (National Security Agency) for encryption of top-secret information.
TripleDES (Data Encryption Standard): officially known as the Triple Data Encryption Algorithm (TDEA or Triple DEA). TripleDES is commonly used within the electronic payments industry as well as in many other well-known services such as Microsoft OneNote, Firefox etc.