Which of the following is NOT a component of a digital signature?

The correct answer highlights an essential concept in digital signatures. A digital signature is primarily composed of the data being signed, a hashing algorithm, and the sender's asymmetric private key.

The data being signed is the actual content that needs protection and integrity verification. The hashing algorithm is crucial because it transforms the data into a fixed-size string of characters, which uniquely represents the data. This ensures that even a slight alteration in the data will result in a completely different hash, indicating that changes have occurred.

The sender's asymmetric private key is vital for creating the digital signature itself; it is used to encrypt the hash of the signed data, ensuring that only the sender can create that signature.

The sender's public key, while important in the broader context of digital signatures, plays a role in verifying the signature, not in its creation. The public key is used by the receiver to decrypt the signature and check that it corresponds to the hash of the received data, thereby proving authenticity and integrity. Thus, it does not belong to the actual components that make up the signature itself.