Final answer:
HMAC is the hashing technology that requires keys to be exchanged, providing message integrity and authenticity through a shared secret key. Salting is a security measure for hashing, MD5 is an insecure hashing function, and AES, although an encryption standard requiring key exchange, is not a hashing technology.
Step-by-step explanation:
The hashing technology that requires keys to be exchanged is HMAC (Hash-based Message Authentication Code). HMAC provides a way to check the integrity and authenticity of a message with the use of a secret key that is shared between the sender and receiver. On the other hand, salting is a technique used to enhance the security of other hashing functions like MD5 by adding a random string to passwords before they are hashed, to prevent attacks such as rainbow table attacks. MD5 is a widely used hash function that produces a 128-bit hash value, but it is not secure for cryptographic purposes and does not require key exchange. AES (Advanced Encryption Standard) is an encryption algorithm that uses symmetric keys for securing data, but it is not a hashing algorithm; however, in the context of requiring key exchange, AES does require that the encryption key is securely shared between the communicating parties.