Secret-key encryption is also known as symmetric-key encryption. In this type of encryption, the same key is used for both the encryption of the plaintext (original data) and the decryption of the ciphertext (encrypted data). The parties involved in the communication need to share this secret key securely for the encryption and decryption processes.
Common symmetric-key encryption algorithms include Advanced Encryption Standard (AES), Data Encryption Standard (DES), and Triple DES (3DES).