ElGamal Digital Signatures finds diverse applications. Which of the following is NOT a typical use case?

Select one:

a$.$ Signing software updates to assure their authenticity and prevent tampering.

b$.$ Securing digital contracts to guarantee non$-$repudiation and tamper$-$proof agreements.

c$.$ Protecting email messages from forgery and verifying the sender$\text{'}$s identity.

d$.$ Encrypting sensitive data where both confidentiality and non$-$repudiation are crucial.