Question: the combination of a public key and a private key is known as a
[{'answer': 'digital signature', 'provenance': [{'wikipedia_id': '24222', 'title': 'Public-key cryptography', 'start_paragraph_id': 3, 'start_character': 109, 'end_paragraph_id': 3, 'end_character': 126, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]