1. Which among the following cannot be used in the case of stream ciphers? a) TRNGs b) PRNGs c) PRFs d) All of the mentioned AnswerAnswer: a [Reason:] TRNGs are not practical for stream ciphers. 2. A stream cipher key is usually of size ___ or 128 bits. a) 56 b) 64 c) 54 d)…