ElGamal Digital Signatures leverage:

Select one:

a$.$ One$-$time pads, rendering each signature unique and unbreakable.

b$.$ Stream ciphers, encrypting the message bit by bit with a keystream.

c$.$ Symmetric$-$key cryptography, where a single key is used for both signing and verifying.

d$.$ Asymmetric$-$key cryptography, where different keys are used for signing and verifying.