JNTU B.Tech IV NETWORK SECURITY AND CRYPTOGRAPHY Previous Question Paper (July - 2023 - R16)

A Block cipher processes input data in fixed-size blocks (e.g., 64 or 128 bits) using a symmetric key, applying the same transformation to each block. In contrast, a Stream cipher processes input data continuously, typically one bit or byte at a time, by combining it with a time-varying keystream generated from the secret key.

Key differences include: block ciphers are generally more complex and suitable for bulk data encryption, while stream ciphers are faster and more efficient for real-time applications where low latency is critical.

Traffic padding is a security technique where dummy data units are inserted into a communication stream to maintain a consistent flow of traffic, regardless of the actual volume of information being transmitted. This process involves adding extra, meaningless bits or packets to the data stream to ensure that the transmission rate remains constant.

The primary purpose of traffic padding is to thwart traffic analysis attacks. By masking the actual patterns of communication, it prevents an adversary from inferring sensitive information—such as the frequency, timing, or volume of real messages—that could otherwise be used to identify the nature of the communication or the identity of the communicating parties, even if the content itself is encrypted.