Differential Cryptanalysis on Block Cipher Skinny with MILP Program

Algorithm 1

#include <stdio.h>

# define N1 300

# define N2 200

# define M 9

int choose(int x[N1][M],int y[N2][M-1])

int i, j, temp;

int z[N1]=;

// How many points are not satisfied for each inequality.

for (i=0;i<N1;i++)

for(j=0;j<N2;j++)

if((x[i]]y[j]+x[i]]y[j]]+x[i]]y[j]]+x[i]]y[j]]+x[i]]y[j]]+x[i]]y[j]]

+x[i]]y[j]]+x[i]]y[j]]+x[i]])<0)

z[i]++;

temp=z; j=0;

// Finding the inequality and its count is the largest.

for(i=1;i<N1;i++)

if(z[i]>temp)

if(temp!=0)

// Delete the points corresponding to the largest inequality.

for(i=0;i<N2;i++)

if(x[j]]y[i]+x[j]]y[i]]+x[j]]y[i]]+x[j]]y[i]]+x[j]]y[i]]+x[j]]y[i]]

+x[j]]y[i]]+x[j]]y[i]]+x[j]]<0)

y[i]=0;y[i]]=0;y[i]]=0;y[i]]=0;y[i]]=0;y[i]]=0;y[i]]=0;

y[i]]=0;

// Output inequality and the number of points that are not satisfied.

for(i=0; i<8;i++)

if(x[j][i]<0∥i==0)

printf(%dx%d,x[j][i],i+1);

else

printf(+%dx%d,x[j][i],i+1);

printf(+%d%6d,x[j]],temp);printf(∖n);

x[j]=0;x[j]]=0;x[j]]=0;x[j]]=0;x[j]]=0;x[j]]=0;x[j]]=0;x[j]]=0;

x[j]]=0;

return temp;

else

return 0;

void main()

//In SageMath, the coefficients of the inequality of the s1-box are obtained.

//Because there are so many points, I’ll just list some of them here.

int a[N1][M]=;

//It doesn’t satisfy the s1-box.

//Because there are so many points, I’ll just list some of them here.

int b[N2][M-1]=;

printf(inequalities counting∖n);

while(choose(a, b)!=0)

choose(a, b);