Definition: A cryptographic key that is used to perform both the cryptographic operation and its inverse, such as encrypting and decrypting or creating and verifying a message authentication code. This means that the same key is required in order to perform both functions.
Symmetric Cryptography explained
Symmetric cryptography is a single cryptographic key that is used with a symmetric-key cryptographic algorithm and is uniquely associated with one or more entities and is not made public (i.e., the key is kept secret). A symmetric key is often called a secret key. The use of the term “secret” in this context does not imply a level of secrecy, but rather implies the need to protect the key from disclosure.
Symmetric encryption is often used for bulk encryption of large amounts of data. It is also largely used to secure data at rest. Some examples are:
- Banking - Payment transactions, such as card payment information
- Data storage- encrypting data stored on a device when that data is not being transferred
- Validating the message of the sender
- Random number generation.
Implementing symmetric cryptography (particularly with hardware) can be highly effective because you do not experience any significant time delay as a result of the encryption and decryption.
One of the primary challenges of symmetric encryption, known as the "key distribution problem," is distributing the key in a secure manner. The key is essential in symmetric cryptography, and we cannot afford to lose or misplace it. Malicious actors can decrypt the message if the individual keys are lost or misplaced. This is why, for data in motion, asymmetric cryptography should be used.
