I am practically implementing a differential cryptanalysis on a cipher which can be found in the book "The Block Cipher Companion". Following image shows the cipher:
In Fig. 6.10 (page 126) there are some evaluations to the probabilities of success to correctly restore the bits 4-8 of k5 depending on a given count of choose messages. I try to compare my implementation with the given results. My problem currently is, that my implementation does not really compare good to the given results. For example: In the book they say, with 32 choosen messages, they restore the bits of k5 with a probability of 64% in 100 cases. I get roughly 28% with my implementation. So may be there is some problem with my implementation or the setup of the tests are a bit different. Is here anybody who implemented the differential cryptanalysis for the cipher in the book "The Block Cipher Companion"? Or does somebody has some test vectors?