00:01
So first let's understand what is the error propagation means.
00:04
It is encryption.
00:10
Error propagation refers to the effect of single bit error in the ciphertext on a decrypted plaintext.
00:24
In some encryption modes, a single bit error in ciphertext can cause the entire block of plaintext to be corrupted, while in others only the corresponding block of plaintiff is affected.
00:37
Now let's consider the four encryption modes mentioned in the task.
00:43
Ecb, cbc, cfb, ofb first in ecb electronic code board, each block of plaintext is encrypted independently using same key.
01:08
This means that a single bit error in the ciphertext will only affect the corresponding block of plaintext and no other blocks.
01:14
Therefore in this case we can recover all the information except for the corrupted block.
01:20
In cbc cipher block chaining, each block of plaintext is xored with previous ciphertext block before inscription.
01:35
This means that a single bit error in ciphertext will affect the corresponding block of the plaintext as well as the next block.
01:41
Therefore in this case we can recover all information up to the corrupted block, but the subsequent blocks will be corrupted...