A szimmetrikus titkosítás (symmetric encryption) is a method of encrypting data where the same key is used for both encryption and decryption. This means that both the sender and the receiver must possess the same secret key to access the original information. It is efficient for encrypting large amounts of data quickly. In szimmetrikus titkosítás, the security of the encrypted data relies heavily on the secrecy of the key. If the key is compromised, anyone with access to it can decrypt the information. Common algorithms used in symmetric encryption include AES (Advanced Encryption Standard) and DES (Data Encryption Standard).