I have tried to answer this question for quite some time now. But a complete intuitive understanding still eludes me:
suggested a new implementation for AES:
The byte substitution step will be replaced by the function: $$s(b_0b_1b_2b_3b_4b_5b_6b_7)\,=\,b_7b_0b_1b_2b_3b_4b_5b_6$$
( a cyclic shift of one bit to the right) The question is: How does this change affect the safety of AES, and how many pairs (p,c) are needed to attack successfully?
Note: I understand that the purpose of the replacement step is to reduce the correlation between the input bits and the output bits at the byte level and that the above implementation weakens the safety, but I don't understand how and why more deeply..