Question

Assume that the ciphertext C is computed from the plaintext P by C= P ⊕ K1 ⊕ K2 , where K1 and K2 are the encryption key and ⊕ denotes the bitwise Xor operation. Also, we know that the ciphertext of P=5 is C=12. What is the encryption key?

a) 9
b) 10
c) 3
d) 0

Answer 1

K1 ⊕ K2 = 9

Step-by-step explanation:

Since 5 ⊕ K = 12, K must be 5 ⊕ 12 = 9.

But there are supposedly two encryptionkeys, we cannot know their individual value, only that K1 ⊕ K2 = 9.

That makes this a bit weird question.