Hard_To_Write

JuliaPoo This challenge was so hard to write. Differential Cryptanalysis Pg 19-29 nc win.the.seetf.sg 3003 Hint: def get_ddt(sbox): l = len(sbox) ddt = np.zeros((l,l), dtype=int) for i,x in enumerate(sbox): for j,y in enumerate(sbox): ddt[i^j][x^y] += 1 return ddt ddt = get_ddt(SBOX) ddt_thres = ddt > 4 plt.imshow(ddt_thres) plt.show() d = dict([(x,y) for x in range(16) for y in range(16) if ddt_thres[x,y]]) DDT_SBOX = np.array([d[i] for i in range(16)], dtype=np.uint64)