Fill in the blank with the appropriate encryption system. The ______ encryption system is an asymmetric key encryption algorithm for the public-key cryptography, which is based on the Diffie- Hellman

ElGamal encryption is built on the mathematical foundation of the Diffie-Hellman key exchange, using the difficulty of the discrete logarithm problem for its security. It is an asymmetric algorithm employing separate public and private keys, which precisely matches the description of a Diffie-Hellman-based public-key cryptosystem in the question stem.

RSA is an asymmetric algorithm but derives its security from the difficulty of factoring large composite numbers (prime factorization), not from the Diffie-Hellman key agreement.

AES (Advanced Encryption Standard) is a symmetric cipher that uses the same key for both encryption and decryption, and has no relationship to Diffie-Hellman or public-key cryptography.

DES (Data Encryption Standard) is a symmetric block cipher that also uses a single shared key, making it unrelated to asymmetric or Diffie-Hellman-based encryption.