# Is there an avalanche effect using block cipher modes of operation?

I am studying cryptography and various block cipher modes of operation.

Suppose I changed one bit in the last block of the message. Wouldn't that imply no change in all encrypted blocks except for the last one?

At least based on the description of how various modes work (CBC, OFB, etc), I don't see why that wouldn't be the case.

However, if that is true, then the encryption mode lacks the avalanche effect property, doesn't it? A single bit change in any place should completely change the encrypted text.

Could someone correct my observation, or explain why lack of avalanche effect is not dangerous?

• there are modes that have the full avalanche effect (like EME) but they're generally not required as any tampering with the data will be detected by the message authentication code (MAC) which then produces an error upon decryption.
– SEJPM
Mar 23 '16 at 13:42
• You cannot have an online (one-pass) mode with the avalanche property. Mar 23 '16 at 13:45