Regarding constructing a good encryption algorithm， what does creating an avalanche effect indicate？（）
- AAltering the key length causes the ciphertext to be completely different
- BChanging only a few bits of a ciphertext message causes the plain text to be completely different
- CAltering the key length causes the plain text to be completely different
- DChanging only a few bits of a plain-text message causes the ciphertext to be completely different