Encryption and Cryptography

Correct Answer: Strong collision resistance

The property that ensures a cryptographic hash function will produce a unique output for every unique input, thereby minimizing the risk of collision attacks, is known as 'Strong collision resistance'. This property makes it computationally infeasible to find two different inputs that would produce the same hash output. While a hash function strives for unique outputs, it is theoretically impossible to guarantee absolute uniqueness due to the infinite number of possible inputs and finite number of outputs. 'Fixed output length' is not directly responsible for uniqueness of output for each input; it simply ensures that the hash function outputs data of a constant size, which is a requirement for many practical uses of hash functions, but does not itself prevent collisions. 'High computational efficiency' refers to the hash function's ability to compute the hash value quickly, which is independent of its collision resistance properties. 'Avalanche effect' is a desirable property where a small change in the input results in a significantly different output, but it does not guarantee that each input has a unique output. Therefore, the concept of 'Strong collision resistance' is the most appropriate answer to the question.

Correct Answer: Digital Signature

A digital signature ensures the authenticity and integrity of the email. The other options are not specifically for this purpose: A Digital Certificate confirms the identity of the sender, Steganography hides the message, TLS secures the connection, Key Exchange establishes a shared key, and Port Security restricts network access.

Correct Answer: TLS

TLS (Transport Layer Security) is the modern and improved version of SSL (Secure Sockets Layer) designed for securing web communication. SSH and SFTP secure file transfers, IPSec secures network communication, and RDP is primarily designed for remote desktop connections.