RSA finds many applications beyond just encrypting messages. Which of the following is NOT a typical use case for RSA?

Select one:

a$.$ Data encryption for storage drives, protecting sensitive information at rest.

b$.$ Key exchange protocols, establishing secure communication channels between parties.

c$.$ Digital signatures, ensuring the authenticity of a message and identifying the sender$.$

d$.$ Secure logins for websites and applications, where passwords are never directly transmitted.