Jeff was explaining to a friend the importance of protecting a cryptographic key from cryptoanalysis. He said that the key should not relate in a simple way to the cipher text. Which protection is Jeff describing?

Jeff is describing confusion

Explanation:

In 1945, Claude Shannon gave a classified report on: "Mathematical Theory of Cryptography" where he stated that confusion and diffusion are two properties of the operation of a secure cipher which are very essential in cryptanalysis.

When each bit of the ciphertext depends on several parts of the key, secluding the connections between the ciphertext and the key, it is known as confusion.

Hence, Jeff saying that the key should not relate in a simple way to the cipher text describes confusion.