Equal corresponding elements of the permutations, resulting from change of key




Test 1. 2^33.2 pairs of 128bit, 2^33.2 pairs of 256bit and 2^33.2 pairs of 512bit keys,
differing by each possible value in each possible (one at a time) position of the key, were
used to generate 256element permutations with the VMPC Key Scheduling Algorithm.
Test 2. 2^33.2 pairs of 128bit, 2^33.2 pairs of 256bit and 2^33.2 pairs of 512bit keys,
differing by each possible value in the last position of the key (the position of the key which
is last to be used for the first time by the KSA), were
used to generate 256element permutations with the VMPC Key Scheduling Algorithm.
In Test 1 and in Test 2  frequencies of occurrence of situations, where the elements in each
of the corresponding positions of the permutations are equal, were measured
Let P1(X) denote Xth element of the permutation generated from one key and P2(X) denote
Xth element the permutation generated from the changed key.
Situations where the corresponding elements of the permutations are equal (P1(X)=P2(X)) should
occur with probability 1/256  for each of the positions (X) of the permutations.
With consideration of the fact that 256 variables were tested  the measured frequencies of
occurrence of these situations for Test 1 and Test 2 showed no
statistically significant deviation from their expected values.
by Bartosz Zoltak

