Certified Information Systems Security Professional – CISSP – Question322

What principle requires that changes to the plaintext affect many parts of the ciphertext?

A.
Encapsulation
B. Permutation
C. Diffusion
D. Obfuscation

Correct Answer: C

Explanation:

Explanation: Diffusion, on the other hand, means that a single plaintext bit has influence over several of the ciphertext bits. Changing a plaintext value should change many ciphertext values, not just one. In fact, in a strong block cipher, if one plaintext bit is changed, it will change every ciphertext bit with the probability of 50 percent. This means that if one plaintext bit changes, then about half of the ciphertext bits will change.