present_sim_dpa.py

# setup & collect

from random import randrange

S = [
    0xC, 0x5, 0x6, 0xB,
    0x9, 0x0, 0xA, 0xD,
    0x3, 0xE, 0xF, 0x8,
    0x4, 0x7, 0x1, 0x2
]

def hw(v):
    return bin(v).count('1')

K = 0xB

ins = [randrange(0, 16) for _ in range(50)]
out = map(lambda x: S[x^K], ins)
met = map(hw, out)

# attack

from scipy.stats.stats import pearsonr

for k in range(16):
    outp = map(lambda x: S[x^k], ins)
    metc = map(hw, outp)

    corr, _ = pearsonr(metc, met)
    print hex(k), corr