Symmetric cryptography, also known as secret key cryptography, is a type of cryptography where a single key is used to encrypt and decrypt data. This key is shared between two parties, and must be kept secret in order to maintain the security of the data. An example of symmetric cryptography is the Advanced Encryption Standard (AES).
Asymmetric cryptography, also known as public key cryptography, is a type of cryptography where two different keys are used to encrypt and decrypt data. One key is used to encrypt the data, and the other is used to decrypt the data. An example of asymmetric cryptography is the RSA algorithm.