Final answer:
The Diffie-Hellman (DH) algorithm is the asymmetric algorithm listed, using a pair of keys for encryption and decryption, which differentiates it from symmetric algorithms like 3DES and AES.
Step-by-step explanation:
The encryption algorithm that is an asymmetric algorithm among the options provided is DH, which stands for Diffie-Hellman. Asymmetric algorithms, also known as public key cryptography, use a pair of keys for encryption and decryption—a public key and a private key. Unlike symmetric algorithms like 3DES (Triple Data Encryption Standard) and AES (Advanced Encryption Standard), which use the same secret key for encryption and decryption, asymmetric algorithms use two distinct keys. SEAL (Software-optimized Encryption Algorithm) is also a symmetric cipher and not asymmetric.