What is the role of a key exchange algorithm?

The role of a key exchange algorithm is fundamentally to securely distribute encryption keys between parties. In cryptography, secure communication oftentimes relies on both parties sharing a common secret key. Key exchange algorithms facilitate this process by ensuring that the key can be shared over potentially insecure channels without the risk of it being intercepted by malicious actors.

Key exchange methods, such as Diffie-Hellman or RSA-based key exchange, allow two parties to generate a shared key independently without transmitting the actual key over the network. This secured distribution is crucial because if encryption keys are compromised, the confidentiality and integrity of the messages encrypted with those keys can be easily undermined.

In contrast, the other options refer to functions that do not align with the purpose of key exchange algorithms. While creating a secondary key for encryption or encrypting and decrypting data are components of the broader cryptographic process, they do not directly relate to the task of securing key distribution.