What type of encryption uses different keys to encrypt and decrypt the message?

Asymmetric encryption utilizes different keys for encryption and decryption, which is fundamental to its operation. In this encryption scheme, a pair of keys is generated: a public key and a private key. The public key is used for encryption, allowing anyone to securely send a message to the key owner, while the private key is kept secret and is used solely by the recipient to decrypt the received message. This dual-key mechanism enhances security, as the public key can be shared openly without compromising the decryption process controlled by the private key.

The other forms of encryption mentioned do not use distinct keys for these processes. For instance, symmetric encryption uses the same key for both encryption and decryption. Hashing is not an encryption method but a one-way function designed to produce a fixed-size output (hash) from input data, typically used for integrity verification. Stream encryption refers to the method of encrypting data in real-time, usually one bit or byte at a time, but it can still involve symmetric key techniques. Therefore, asymmetric encryption's use of separate keys distinctly sets it apart as the correct answer in this context.