Symmetric cryptography also known as secret key cryptography, has been in use for thousands of years in forms ranging from simple substitution ciphers to more complex constructions. However, developments in mathematics and the growth of computing power have made it possible to create ciphers that are effectively unbreakable.
To encrypt and decrypt the data symmetric cryptography uses a single private key. The party having this key can use it to encrypt and decrypt data.
The algorithm used in symmetric cryptography is fast and suitable for processing large streams of data.
Disadvantage of Symmetric Cryptography:
The disadvantage of symmetric cryptography is that it presumes two parties have agreed on a key and been able to exchange that key in a secure manner prior to communication. This is a significant challenge. Symmetric algorithms are usually mixed with public key algorithms to obtain a blend of security and speed.