How to prove a cipher resistant to differential cryptanalysis? How do you prove that a cipher is resistant to differential cryptanalysis? It's said that Rijndael has been proven resistance to differential cryptanalysis. How do cryptographers do that?
The design documents for Rijndael explain exactly how the designers proved its resistance to differential cryptanalysis.

Read their submission to the AES competition process, particularly Section 8.2 and the Annex.  To understand their approach, it will probably help to understand differential cryptanalysis and read some of the related literature.  You can find a more detailed explanation in their book, The Design of Rijndael: AES.

You might enjoy the following research papers:


The Wide Trail Design Strategy
Provable Security against Differential and Linear
Cryptanalysis for the SPN Structure