Which one of the following is not a public-key cryptographic algorithm?

DES (Data Encryption Standard) is a symmetric-key algorithm, which means it uses the same secret key for both encryption and decryption. Developed in the 1970s by IBM, it is now considered insecure for modern data protection due to its short 56-bit key length and has been largely superseded by the Advanced Encryption Standard (AES).

• RSA (Rivest-Shamir-Adleman): One of the first and most widely used public-key (asymmetric) algorithms for secure data transmission.
• Diffie-Hellman: A specific method of public-key cryptography used for secure key exchange over a public channel.
• DSS (Digital Signature Standard): A federal standard that uses public-key cryptography (specifically the Digital Signature Algorithm or DSA) to provide digital signatures.