This next question is about an application of symmetric ciphers.
To exploit the BEAST vulnerability in HTTPS,
suppose an attacker has intercepted the ciphertext, using 4-bit blocks.
C0, the first block of the intercepted ciphertext, is 1000
as the result of encrypting m0, the first block in the message.
C1 is the result of encrypting the second block of the message,
and C2 the result of encrypting the third block of the message.
Our attacker wants to find if m1, the second block in the intercepted message
is equal to 1010.
The question is what should the attacker use as the target value for m0',
which is the first block and the next response.
Your answer should be 4 bits long.
