A cryptographic strong hash function may be obtained using the following method: A$.$ Using a $CBC$ mode of a compression function based on a public $-$ key encryption algorithm B$.$ None of the above $C.$ Using a simple checksum mechanisms for error detection $D.$ Using a cryptographically strong compression function $E.$ Using a $CBC$ mode of a compression function based on a strong symmetric $-$ key encryption algorithm $2.$ In the following list of questions regarding authentication, which one is the best answer? A$.$ Let $H$ be a hash function with output length $m.$ Then the square root of the $m-$ th power of $2$ is the upper bound of the cryptographic strength of $H$ becasue of birthday attacks. B$.$ Hash functions are used in authentication for the purpose of speeding up calculations and reducing network traffic. C$.$ The strength of SHA$-160$ is at least the $79$th power of $D.$ All of the above. $E.$ All of the above except $3.$ F$.$ None of the above.